meaning of argument in critical thinking

Pursuing Truth: A Guide to Critical Thinking

Chapter 2 arguments.

The fundamental tool of the critical thinker is the argument. For a good example of what we are not talking about, consider a bit from a famous sketch by Monty Python’s Flying Circus : 3

2.1 Identifying Arguments

People often use “argument” to refer to a dispute or quarrel between people. In critical thinking, an argument is defined as

A set of statements, one of which is the conclusion and the others are the premises.

There are three important things to remember here:

• Arguments contain statements.
• They have a conclusion.
• They have at least one premise

Arguments contain statements, or declarative sentences. Statements, unlike questions or commands, have a truth value. Statements assert that the world is a particular way; questions do not. For example, if someone asked you what you did after dinner yesterday evening, you wouldn’t accuse them of lying. When the world is the way that the statement says that it is, we say that the statement is true. If the statement is not true, it is false.

One of the statements in the argument is called the conclusion. The conclusion is the statement that is intended to be proved. Consider the following argument:

Calculus II will be no harder than Calculus I. Susan did well in Calculus I. So, Susan should do well in Calculus II.

Here the conclusion is that Susan should do well in Calculus II. The other two sentences are premises. Premises are the reasons offered for believing that the conclusion is true.

2.1.1 Standard Form

Now, to make the argument easier to evaluate, we will put it into what is called “standard form.” To put an argument in standard form, write each premise on a separate, numbered line. Draw a line underneath the last premise, the write the conclusion underneath the line.

• Calculus II will be no harder than Calculus I.
• Susan did well in Calculus I.
• Susan should do well in Calculus II.

Now that we have the argument in standard form, we can talk about premise 1, premise 2, and all clearly be referring to the same thing.

2.1.2 Indicator Words

Unfortunately, when people present arguments, they rarely put them in standard form. So, we have to decide which statement is intended to be the conclusion, and which are the premises. Don’t make the mistake of assuming that the conclusion comes at the end. The conclusion is often at the beginning of the passage, but could even be in the middle. A better way to identify premises and conclusions is to look for indicator words. Indicator words are words that signal that statement following the indicator is a premise or conclusion. The example above used a common indicator word for a conclusion, ‘so.’ The other common conclusion indicator, as you can probably guess, is ‘therefore.’ This table lists the indicator words you might encounter.

Each argument will likely use only one indicator word or phrase. When the conlusion is at the end, it will generally be preceded by a conclusion indicator. Everything else, then, is a premise. When the conclusion comes at the beginning, the next sentence will usually be introduced by a premise indicator. All of the following sentences will also be premises.

For example, here’s our previous argument rewritten to use a premise indicator:

Susan should do well in Calculus II, because Calculus II will be no harder than Calculus I, and Susan did well in Calculus I.

Sometimes, an argument will contain no indicator words at all. In that case, the best thing to do is to determine which of the premises would logically follow from the others. If there is one, then it is the conclusion. Here is an example:

Spot is a mammal. All dogs are mammals, and Spot is a dog.

The first sentence logically follows from the others, so it is the conclusion. When using this method, we are forced to assume that the person giving the argument is rational and logical, which might not be true.

2.1.3 Non-Arguments

One thing that complicates our task of identifying arguments is that there are many passages that, although they look like arguments, are not arguments. The most common types are:

• Explanations
• Mere asssertions
• Conditional statements
• Loosely connected statements

Explanations can be tricky, because they often use one of our indicator words. Consider this passage:

Abraham Lincoln died because he was shot.

If this were an argument, then the conclusion would be that Abraham Lincoln died, since the other statement is introduced by a premise indicator. If this is an argument, though, it’s a strange one. Do you really think that someone would be trying to prove that Abraham Lincoln died? Surely everyone knows that he is dead. On the other hand, there might be people who don’t know how he died. This passage does not attempt to prove that something is true, but instead attempts to explain why it is true. To determine if a passage is an explanation or an argument, first find the statement that looks like the conclusion. Next, ask yourself if everyone likely already believes that statement to be true. If the answer to that question is yes, then the passage is an explanation.

Mere assertions are obviously not arguments. If a professor tells you simply that you will not get an A in her course this semester, she has not given you an argument. This is because she hasn’t given you any reasons to believe that the statement is true. If there are no premises, then there is no argument.

Conditional statements are sentences that have the form “If…, then….” A conditional statement asserts that if something is true, then something else would be true also. For example, imagine you are told, “If you have the winning lottery ticket, then you will win ten million dollars.” What is being claimed to be true, that you have the winning lottery ticket, or that you will win ten million dollars? Neither. The only thing claimed is the entire conditional. Conditionals can be premises, and they can be conclusions. They can be parts of arguments, but that cannot, on their own, be arguments themselves.

Finally, consider this passage:

I woke up this morning, then took a shower and got dressed. After breakfast, I worked on chapter 2 of the critical thinking text. I then took a break and drank some more coffee….

This might be a description of my day, but it’s not an argument. There’s nothing in the passage that plays the role of a premise or a conclusion. The passage doesn’t attempt to prove anything. Remember that arguments need a conclusion, there must be something that is the statement to be proved. Lacking that, it simply isn’t an argument, no matter how much it looks like one.

2.2 Evaluating Arguments

The first step in evaluating an argument is to determine what kind of argument it is. We initially categorize arguments as either deductive or inductive, defined roughly in terms of their goals. In deductive arguments, the truth of the premises is intended to absolutely establish the truth of the conclusion. For inductive arguments, the truth of the premises is only intended to establish the probable truth of the conclusion. We’ll focus on deductive arguments first, then examine inductive arguments in later chapters.

Once we have established that an argument is deductive, we then ask if it is valid. To say that an argument is valid is to claim that there is a very special logical relationship between the premises and the conclusion, such that if the premises are true, then the conclusion must also be true. Another way to state this is

An argument is valid if and only if it is impossible for the premises to be true and the conclusion false.

An argument is invalid if and only if it is not valid.

Note that claiming that an argument is valid is not the same as claiming that it has a true conclusion, nor is it to claim that the argument has true premises. Claiming that an argument is valid is claiming nothing more that the premises, if they were true , would be enough to make the conclusion true. For example, is the following argument valid or not?

• If pigs fly, then an increase in the minimum wage will be approved next term.
• An increase in the minimum wage will be approved next term.

The argument is indeed valid. If the two premises were true, then the conclusion would have to be true also. What about this argument?

• All dogs are mammals
• Spot is a mammal.
• Spot is a dog.

In this case, both of the premises are true and the conclusion is true. The question to ask, though, is whether the premises absolutely guarantee that the conclusion is true. The answer here is no. The two premises could be true and the conclusion false if Spot were a cat, whale, etc.

Neither of these arguments are good. The second fails because it is invalid. The two premises don’t prove that the conclusion is true. The first argument is valid, however. So, the premises would prove that the conclusion is true, if those premises were themselves true. Unfortunately, (or fortunately, I guess, considering what would be dropping from the sky) pigs don’t fly.

These examples give us two important ways that deductive arguments can fail. The can fail because they are invalid, or because they have at least one false premise. Of course, these are not mutually exclusive, an argument can be both invalid and have a false premise.

If the argument is valid, and has all true premises, then it is a sound argument. Sound arguments always have true conclusions.

A deductively valid argument with all true premises.

Inductive arguments are never valid, since the premises only establish the probable truth of the conclusion. So, we evaluate inductive arguments according to their strength. A strong inductive argument is one in which the truth of the premises really do make the conclusion probably true. An argument is weak if the truth of the premises fail to establish the probable truth of the conclusion.

There is a significant difference between valid/invalid and strong/weak. If an argument is not valid, then it is invalid. The two categories are mutually exclusive and exhaustive. There can be no such thing as an argument being more valid than another valid argument. Validity is all or nothing. Inductive strength, however, is on a continuum. A strong inductive argument can be made stronger with the addition of another premise. More evidence can raise the probability of the conclusion. A valid argument cannot be made more valid with an additional premise. Why not? If the argument is valid, then the premises were enough to absolutely guarantee the truth of the conclusion. Adding another premise won’t give any more guarantee of truth than was already there. If it could, then the guarantee wasn’t absolute before, and the original argument wasn’t valid in the first place.

2.3 Counterexamples

One way to prove an argument to be invalid is to use a counterexample. A counterexample is a consistent story in which the premises are true and the conclusion false. Consider the argument above:

By pointing out that Spot could have been a cat, I have told a story in which the premises are true, but the conclusion is false.

Here’s another one:

• If it is raining, then the sidewalks are wet.
• The sidewalks are wet.
• It is raining.

The sprinklers might have been on. If so, then the sidewalks would be wet, even if it weren’t raining.

Counterexamples can be very useful for demonstrating invalidity. Keep in mind, though, that validity can never be proved with the counterexample method. If the argument is valid, then it will be impossible to give a counterexample to it. If you can’t come up with a counterexample, however, that does not prove the argument to be valid. It may only mean that you’re not creative enough.

• An argument is a set of statements; one is the conclusion, the rest are premises.
• The conclusion is the statement that the argument is trying to prove.
• The premises are the reasons offered for believing the conclusion to be true.
• Explanations, conditional sentences, and mere assertions are not arguments.
• Deductive reasoning attempts to absolutely guarantee the truth of the conclusion.
• Inductive reasoning attempts to show that the conclusion is probably true.
• In a valid argument, it is impossible for the premises to be true and the conclusion false.
• In an invalid argument, it is possible for the premises to be true and the conclusion false.
• A sound argument is valid and has all true premises.
• An inductively strong argument is one in which the truth of the premises makes the the truth of the conclusion probable.
• An inductively weak argument is one in which the truth of the premises do not make the conclusion probably true.
• A counterexample is a consistent story in which the premises of an argument are true and the conclusion is false. Counterexamples can be used to prove that arguments are deductively invalid.

( Cleese and Chapman 1980 ) . ↩︎

Internet Encyclopedia of Philosophy

Critical thinking.

Critical Thinking is the process of using and assessing reasons to evaluate statements, assumptions, and arguments in ordinary situations. The goal of this process is to help us have good beliefs, where “good” means that our beliefs meet certain goals of thought, such as truth, usefulness, or rationality. Critical thinking is widely regarded as a species of informal logic, although critical thinking makes use of some formal methods. In contrast with formal reasoning processes that are largely restricted to deductive methods—decision theory, logic, statistics—the process of critical thinking allows a wide range of reasoning methods, including formal and informal logic, linguistic analysis, experimental methods of the sciences, historical and textual methods, and philosophical methods, such as Socratic questioning and reasoning by counterexample.

The goals of critical thinking are also more diverse than those of formal reasoning systems. While formal methods focus on deductive validity and truth, critical thinkers may evaluate a statement’s truth, its usefulness, its religious value, its aesthetic value, or its rhetorical value. Because critical thinking arose primarily from the Anglo-American philosophical tradition (also known as “analytic philosophy”), contemporary critical thinking is largely concerned with a statement’s truth. But some thinkers, such as Aristotle (in Rhetoric ), give substantial attention to rhetorical value.

The primary subject matter of critical thinking is the proper use and goals of a range of reasoning methods, how they are applied in a variety of social contexts, and errors in reasoning. This article also discusses the scope and virtues of critical thinking.

Critical thinking should not be confused with Critical Theory. Critical Theory refers to a way of doing philosophy that involves a moral critique of culture. A “critical” theory, in this sense, is a theory that attempts to disprove or discredit a widely held or influential idea or way of thinking in society. Thus, critical race theorists and critical gender theorists offer critiques of traditional views and latent assumptions about race and gender. Critical theorists may use critical thinking methodology, but their subject matter is distinct, and they also may offer critical analyses of critical thinking itself.

Table of Contents

• Argument and Evaluation
• Categorical Logic
• Propositional Logic
• Modal Logic
• Predicate Logic
• Other Formal Systems
• Generalization
• Causal Reasoning
• Formal Fallacies
• Informal Fallacies
• Heuristics and Biases
• The Principle of Charity/Humility
• The Principle of Caution
• The Expansiveness of Critical Thinking
• Productivity and the Limits of Rationality
• Classical Approaches
• The Paul/Elder Model
• Other Approaches
• References and Further Reading

The process of evaluating a statement traditionally begins with making sure we understand it; that is, a statement must express a clear meaning. A statement is generally regarded as clear if it expresses a proposition , which is the meaning the author of that statement intends to express, including definitions, referents of terms, and indexicals, such as subject, context, and time. There is significant controversy over what sort of “entity” propositions are, whether abstract objects or linguistic constructions or something else entirely. Whatever its metaphysical status, it is used here simply to refer to whatever meaning a speaker intends to convey in a statement.

The difficulty with identifying intended propositions is that we typically speak and think in natural languages (English, Swedish, French), and natural languages can be misleading. For instance, two different sentences in the same natural language may express the same proposition, as in these two English sentences:

Jamie is taller than his father. Jamie’s father is shorter than he.

Further, the same sentence in a natural language can express more than one proposition depending on who utters it at a time:

I am shorter than my father right now.

The pronoun “I” is an indexical; it picks out, or “indexes,” whoever utters the sentence and, therefore, expresses a different proposition for each new speaker who utters it. Similarly, “right now” is a temporal indexical; it indexes the time the sentence is uttered. The proposition it is used to express changes each new time the sentence is uttered and, therefore, may have a different truth value at different times (as, say, the speaker grows taller: “I am now five feet tall” may be true today, but false a year from now). Other indexical terms that can affect the meaning of the sentence include other pronouns (he, she, it) and definite articles (that, the).

Further still, different sentences in different natural languages may express the same proposition . For example, all of the following express the proposition “Snow is white”:

Snow is white. (English)

Der Schnee ist weiss. (German)

La neige est blanche. (French)

La neve é bianca. (Italian)

Finally, statements in natural languages are often vague or ambiguous , either of which can obscure the propositions actually intended by their authors. And even in cases where they are not vague or ambiguous, statements’ truth values sometimes vary from context to context. Consider the following example.

The English statement, “It is heavy,” includes the pronoun “it,” which (when used without contextual clues) is ambiguous because it can index any impersonal subject. If, in this case, “it” refers to the computer on which you are reading this right now, its author intends to express the proposition, “The computer on which you are reading this right now is heavy.” Further, the term “heavy” reflects an unspecified standard of heaviness (again, if contextual clues are absent). Assuming we are talking about the computer, it may be heavy relative to other computer models but not to automobiles. Further still, even if we identify or invoke a standard of heaviness by which to evaluate the appropriateness of its use in this context, there may be no weight at which an object is rightly regarded as heavy according to that standard. (For instance, is an object heavy because it weighs 5.3 pounds but not if it weighs 5.2 pounds? Or is it heavy when it is heavier than a mouse but lighter than an anvil?) This means “heavy” is a vague term. In order to construct a precise statement, vague terms (heavy, cold, tall) must often be replaced with terms expressing an objective standard (pounds, temperature, feet).

Part of the challenge of critical thinking is to clearly identify the propositions (meanings) intended by those making statements so we can effectively reason about them. The rules of language help us identify when a term or statement is ambiguous or vague, but they cannot, by themselves, help us resolve ambiguity or vagueness. In many cases, this requires assessing the context in which the statement is made or asking the author what she intends by the terms. If we cannot discern the meaning from the context and we cannot ask the author, we may stipulate a meaning, but this requires charity, to stipulate a plausible meaning, and humility, to admit when we discover that our stipulation is likely mistaken.

2. Argument and Evaluation

Once we are satisfied that a statement is clear, we can begin evaluating it. A statement can be evaluated according to a variety of standards. Commonly, statements are evaluated for truth, usefulness, or rationality. The most common of these goals is truth, so that is the focus of this article.

The truth of a statement is most commonly evaluated in terms of its relation to other statements and direct experiences. If a statement follows from or can be inferred from other statements that we already have good reasons to believe, then we have a reason to believe that statement. For instance, the statement “The ball is blue” can be derived from “The ball is blue and round.” Similarly, if a statement seems true in light of, or is implied by, an experience, then we have a reason to believe that statement. For instance, the experience of seeing a red car is a reason to believe, “The car is red.” (Whether these reasons are good enough for us to believe is a further question about justification , which is beyond the scope of this article, but see “ Epistemic Justification .”) Any statement we derive in these ways is called a conclusion . Though we regularly form conclusions from other statements and experiences—often without thinking about it—there is still a question of whether these conclusions are true: Did we draw those conclusions well? A common way to evaluate the truth of a statement is to identify those statements and experiences that support our conclusions and organize them into structures called arguments . (See also, “ Argument .”)

An argument is one or more statements (called premises ) intended to support the truth of another statement (the conclusion ). Premises comprise the evidence offered in favor of the truth of a conclusion. It is important to entertain any premises that are intended to support a conclusion, even if the attempt is unsuccessful. Unsuccessful attempts at supporting a proposition constitute bad arguments, but they are still arguments. The support intended for the conclusion may be formal or informal. In a formal, or deductive, argument, an arguer intends to construct an argument such that, if the premises are true, the conclusion must be true. This strong relationship between premises and conclusion is called validity . This relationship between the premises and conclusion is called “formal” because it is determined by the form (that is, the structure) of the argument (see §3). In an informal, or inductive , argument, the conclusion may be false even if the premises are true. In other words, whether an inductive argument is good depends on something more than the form of the argument. Therefore, all inductive arguments are invalid, but this does not mean they are bad arguments. Even if an argument is invalid, its premises can increase the probability that its conclusion is true. So, the form of inductive arguments is evaluated in terms of the strength the premises confer on the conclusion, and stronger inductive arguments are preferred to weaker ones (see §4). (See also, “ Deductive and Inductive Arguments .”)

Psychological states, such as sensations, memories, introspections, and intuitions often constitute evidence for statements. Although these states are not themselves statements, they can be expressed as statements. And when they are, they can be used in and evaluated by arguments. For instance, my seeing a red wall is evidence for me that, “There is a red wall,” but the physiological process of seeing is not a statement. Nevertheless, the experience of seeing a red wall can be expressed as the proposition, “I see a red wall” and can be included in an argument such as the following:

• I see a red wall in front of me.
• Therefore, there is a red wall in front of me.

This is an inductive argument, though not a strong one. We do not yet know whether seeing something (under these circumstances) is reliable evidence for the existence of what I am seeing. Perhaps I am “seeing” in a dream, in which case my seeing is not good evidence that there is a wall. For similar reasons, there is also reason to doubt whether I am actually seeing. To be cautious, we might say we seem to see a red wall.

To be good , an argument must meet two conditions: the conclusion must follow from the premises—either validly or with a high degree of likelihood—and the premises must be true. If the premises are true and the conclusion follows validly, the argument is sound . If the premises are true and the premises make the conclusion probable (either objectively or relative to alternative conclusions), the argument is cogent .

Here are two examples:

• Earth is larger than its moon.
• Our sun is larger than Earth.
• Therefore, our sun is larger than Earth’s moon.

In example 1, the premises are true. And since “larger than” is a transitive relation, the structure of the argument guarantees that, if the premises are true, the conclusion must be true. This means the argument is also valid. Since it is both valid and has true premises, this deductive argument is sound.

  Example 2:

• It is sunny in Montana about 205 days per year.
• I will be in Montana in February.
• Hence, it will probably be sunny when I am in Montana.

In example 2, premise 1 is true, and let us assume premise 2 is true. The phrase “almost always” indicates that a majority of days in Montana are sunny, so that, for any day you choose, it will probably be a sunny day. Premise 2 says I am choosing days in February to visit. Together, these premises strongly support (though they do not guarantee) the conclusion that it will be sunny when I am there, and so this inductive argument is cogent.

In some cases, arguments will be missing some important piece, whether a premise or a conclusion. For instance, imagine someone says, “Well, she asked you to go, so you have to go.” The idea that you have to go does not follow logically from the fact that she asked you to go without more information. What is it about her asking you to go that implies you have to go? Arguments missing important information are called enthymemes . A crucial part of critical thinking is identifying missing or assumed information in order to effectively evaluate an argument. In this example, the missing premise might be that, “She is your boss, and you have to do what she asks you to do.” Or it might be that, “She is the woman you are interested in dating, and if you want a real chance at dating her, you must do what she asks.” Before we can evaluate whether her asking implies that you have to go, we need to know this missing bit of information. And without that missing bit of information, we can simply reply, “That conclusion doesn’t follow from that premise.”

The two categories of reasoning associated with soundness and cogency—formal and informal, respectively—are considered, by some, to be the only two types of argument. Others add a third category, called abductive reasoning, according to which one reasons according to the rules of explanation rather than the rules of inference . Those who do not regard abductive reasoning as a third, distinct category typically regard it as a species of informal reasoning. Although abductive reasoning has unique features, here it is treated, for reasons explained in §4d, as a species of informal reasoning, but little hangs on this characterization for the purposes of this article.

3. Formal Reasoning

Although critical thinking is widely regarded as a type of informal reasoning, it nevertheless makes substantial use of formal reasoning strategies. Formal reasoning is deductive , which means an arguer intends to infer or derive a proposition from one or more propositions on the basis of the form or structure exhibited by the premises. Valid argument forms guarantee that particular propositions can be derived from them. Some forms look like they make such guarantees but fail to do so (we identify these as formal fallacies in §5a). If an arguer intends or supposes that a premise or set of premises guarantee a particular conclusion, we may evaluate that argument form as deductive even if the form fails to guarantee the conclusion, and is thus discovered to be invalid.

Before continuing in this section, it is important to note that, while formal reasoning provides a set of strict rules for drawing valid inferences, it cannot help us determine the truth of many of our original premises or our starting assumptions. And in fact, very little critical thinking that occurs in our daily lives (unless you are a philosopher, engineer, computer programmer, or statistician) involves formal reasoning. When we make decisions about whether to board an airplane, whether to move in with our significant others, whether to vote for a particular candidate, whether it is worth it to drive ten miles faster the speed limit even if I am fairly sure I will not get a ticket, whether it is worth it to cheat on a diet, or whether we should take a job overseas, we are reasoning informally. We are reasoning with imperfect information (I do not know much about my flight crew or the airplane’s history), with incomplete information (no one knows what the future is like), and with a number of built-in biases, some conscious (I really like my significant other right now), others unconscious (I have never gotten a ticket before, so I probably will not get one this time). Readers who are more interested in these informal contexts may want to skip to §4.

An argument form is a template that includes variables that can be replaced with sentences. Consider the following form (found within the formal system known as sentential logic ):

• If p, then q.
• Therefore, q.

This form was named modus ponens (Latin, “method of putting”) by medieval philosophers. p and q are variables that can be replaced with any proposition, however simple or complex. And as long as the variables are replaced consistently (that is, each instance of p is replaced with the same sentence and the same for q ), the conclusion (line 3), q , follows from these premises. To be more precise, the inference from the premises to the conclusion is valid . “Validity” describes a particular relationship between the premises and the conclusion, namely: in all cases , the conclusion follows necessarily from the premises, or, to use more technical language, the premises logically guarantee an instance of the conclusion.

Notice we have said nothing yet about truth . As critical thinkers, we are interested, primarily, in evaluating the truth of sentences that express propositions, but all we have discussed so far is a type of relationship between premises and conclusion (validity). This formal relationship is analogous to grammar in natural languages and is known in both fields as syntax . A sentence is grammatically correct if its syntax is appropriate for that language (in English, for example, a grammatically correct simple sentence has a subject and a predicate—“He runs.” “Laura is Chairperson.”—and it is grammatically correct regardless of what subject or predicate is used—“Jupiter sings.”—and regardless of whether the terms are meaningful—“Geflorble rowdies.”). Whether a sentence is meaningful, and therefore, whether it can be true or false, depends on its semantics , which refers to the meaning of individual terms (subjects and predicates) and the meaning that emerges from particular orderings of terms. Some terms are meaningless—geflorble; rowdies—and some orderings are meaningless even though their terms are meaningful—“Quadruplicity drinks procrastination,” and “Colorless green ideas sleep furiously.”.

Despite the ways that syntax and semantics come apart, if sentences are meaningful, then syntactic relationships between premises and conclusions allow reasoners to infer truth values for conclusions. Because of this, a more common definition of validity is this: it is not possible for all the premises to be true and the conclusion false . Formal logical systems in which syntax allows us to infer semantic values are called truth-functional or truth-preserving —proper syntax preserves truth throughout inferences.

The point of this is to note that formal reasoning only tells us what is true if we already know our premises are true. It cannot tell us whether our experiences are reliable or whether scientific experiments tell us what they seem to tell us. Logic can be used to help us determine whether a statement is true, but only if we already know some true things. This is why a broad conception of critical thinking is so important: we need many different tools to evaluate whether our beliefs are any good.

Consider, again, the form modus ponens , and replace p with “It is a cat” and q with “It is a mammal”:

• If it is a cat, then it is a mammal.
• It is a cat.
• Therefore, it is a mammal.

In this case, we seem to “see” (in a metaphorical sense of see ) that the premises guarantee the truth of the conclusion. On reflection, it is also clear that the premises might not be true; for instance, if “it” picks out a rock instead of a cat, premise 1 is still true, but premise 2 is false. It is also possible for the conclusion to be true when the premises are false. For instance, if the “it” picks out a dog instead of a cat, the conclusion “It is a mammal” is true. But in that case, the premises do not guarantee that conclusion; they do not constitute a reason to believe the conclusion is true.

Summing up, an argument is valid if its premises logically guarantee an instance of its conclusion (syntactically), or if it is not possible for its premises to be true and its conclusion false (semantically). Logic is truth-preserving but not truth-detecting; we still need evidence that our premises are true to use logic effectively.

            A Brief Technical Point

Some readers might find it worth noting that the semantic definition of validity has two counterintuitive consequences. First, it implies that any argument with a necessarily true conclusion is valid. Notice that the condition is phrased hypothetically: if the premises are true, then the conclusion cannot be false. This condition is met if the conclusion cannot be false:

• Two added to two equals four.

This is because the hypothetical (or “conditional”) statement would still be true even if the premises were false:

• If it is blue, then it flies.
• It is an airplane.

It is true of this argument that if the premises were true, the conclusion would be since the conclusion is true no matter what.

Second, the semantic formulation also implies that any argument with necessarily false premises is valid. The semantic condition for validity is met if the premises cannot be true:

• Some bachelors are married.
• Earth’s moon is heavier than Jupiter.

In this case, if the premise were true, the conclusion could not be false (this is because anything follows syntactically from a contradiction), and therefore, the argument is valid. There is nothing particularly problematic about these two consequences. But they highlight unexpected implications of our standard formulations of validity, and they show why there is more to good arguments than validity.

Despite these counterintuitive implications, valid reasoning is essential to thinking critically because it is a truth-preserving strategy: if deductive reasoning is applied to true premises, true conclusions will result.

There are a number of types of formal reasoning, but here we review only some of the most common: categorical logic, propositional logic, modal logic, and predicate logic.

a. Categorical Logic

Categorical logic is formal reasoning about categories or collections of subjects, where subjects refers to anything that can be regarded as a member of a class, whether objects, properties, or events or even a single object, property, or event. Categorical logic employs the quantifiers “all,” “some,” and “none” to refer to the members of categories, and categorical propositions are formulated in four ways:

A claims: All As are Bs (where the capitals “A” and “B” represent categories of subjects).

E claims: No As are Bs.

I claims: Some As are Bs.

O claims: Some As are not Bs.

Categorical syllogisms are syllogisms (two-premised formal arguments) that employ categorical propositions. Here are two examples:

• All cats are mammals. (A claim) 1. No bachelors are married. (E claim)
• Some cats are furry. (I claim) 2. All the people in this building are bachelors. (A claim)
• Therefore, some mammals are furry. (I claim) 3. Thus, no people in this building are married. (E claim)

There are interesting limitations on what categorical logic can do. For instance, if one premise says that, “Some As are not Bs,” may we infer that some As are Bs, in what is known as an “existential assumption”? Aristotle seemed to think so ( De Interpretatione ), but this cannot be decided within the rules of the system. Further, and counterintuitively, it would mean that a proposition such as, “Some bachelors are not married,” is false since it implies that some bachelors are married.

Another limitation on categorical logic is that arguments with more than three categories cannot be easily evaluated for validity. The standard method for evaluating the validity of categorical syllogisms is the Venn diagram (named after John Venn, who introduced it in 1881), which expresses categorical propositions in terms of two overlapping circles and categorical arguments in terms of three overlapping circles, each circle representing a category of subjects.

Venn diagram for claim and Venn diagram for argument

A, B, and C represent categories of objects, properties, or events. The symbol “ ∩ ” comes from mathematical set theory to indicate “intersects with.” “A∩B” means all those As that are also Bs and vice versa. 

Though there are ways of constructing Venn diagrams with more than three categories, determining the validity of these arguments using Venn diagrams is very difficult (and often requires computers). These limitations led to the development of more powerful systems of formal reasoning.

b. Propositional Logic

Propositional, or sentential , logic has advantages and disadvantages relative to categorical logic. It is more powerful than categorical logic in that it is not restricted in the number of terms it can evaluate, and therefore, it is not restricted to the syllogistic form. But it is weaker than categorical logic in that it has no operators for quantifying over subjects, such as “all” or “some.” For those, we must appeal to predicate logic (see §3c below).

Basic propositional logic involves formal reasoning about propositions (as opposed to categories), and its most basic unit of evaluation is the atomic proposition . “Atom” means the smallest indivisible unit of something, and simple English statements (subject + predicate) are atomic wholes because if either part is missing, the word or words cease to be a statement, and therefore ceases to be capable of expressing a proposition. Atomic propositions are simple subject-predicate combinations, for instance, “It is a cat” and “I am a mammal.” Variable letters such as p and q in argument forms are replaced with semantically rich constants, indicated by capital letters, such as A and B . Consider modus ponens again (noting that the atomic propositions are underlined in the English argument):

As you can see from premise 1 of the Semantic Replacement, atomic propositions can be combined into more complex propositions using symbols that represent their logical relationships (such as “If…, then…”). These symbols are called “operators” or “connectives.” The five standard operators in basic propositional logic are:

These operations allow us to identify valid relations among propositions: that is, they allow us to formulate a set of rules by which we can validly infer propositions from and validly replace them with others. These rules of inference (such as modus ponens ; modus tollens ; disjunctive syllogism) and rules of replacement (such as double negation; contraposition; DeMorgan’s Law) comprise the syntax of propositional logic, guaranteeing the validity of the arguments employing them.

Two Rules of Inference:

Two Rules of Replacement:

For more, see “ Propositional Logic .”

c. Modal Logic

Standard propositional logic does not capture every type of proposition we wish to express (recall that it does not allow us to evaluate categorical quantifiers such as “all” or “some”). It also does not allow us to evaluate propositions expressed as possibly true or necessarily true, modifications that are called modal operators or modal quantifiers .

Modal logic refers to a family of formal propositional systems, the most prominent of which includes operators for necessity (□) and possibility (◊) (see §3d below for examples of other modal systems). If a proposition, p , is possibly true, ◊ p , it may or may not be true. If p is necessarily true, □ p , it must be true; it cannot be false. If p is necessarily false, either ~◊ p or □~ p , it must be false; it cannot be true.

There is a variety of modal systems, the weakest of which is called K (after Saul Kripke, who exerted important influence on the development of modal logic), and it involves only two additional rules:

Necessitation Rule:   If  A  is a theorem of  K , then so is □ A .

Distribution Axiom:  □( A ⊃ B ) ⊃ (□ A ⊃□ B ).  [If it is necessarily the case that if A, then B , then if it is necessarily the case that A, it is necessarily the case that B .]

Other systems maintain these rules and add others for increasing strength. For instance, the (S4) modal system includes axiom (4):

(4)  □ A ⊃ □□ A   [If it is necessarily the case that A, then it is necessarily necessary that A.]

An influential and intuitive way of thinking about modal concepts is the idea of “possible worlds” (see Plantinga, 1974; Lewis 1986). A world is just the set of all true propositions. The actual world is the set of all actually true propositions—everything that was true, is true, and (depending on what you believe about the future) will be true. A possible world is a way the actual world might have been. Imagine you wore green underwear today. The actual world might have been different in that way: you might have worn blue underwear. In this interpretation of modal quantifiers, there is a possible world in which you wore blue underwear instead of green underwear. And for every possibility like this, and every combination of those possibilities, there is a distinct possible world.

If a proposition is not possible, then there is no possible world in which that proposition is true. The statement, “That object is red all over and blue all over at the same time” is not true in any possible worlds. Therefore, it is not possible (~◊P), or, in other words, necessarily false (□~P). If a proposition is true in all possible worlds, it is necessarily true. For instance, the proposition, “Two plus two equal four,” is true in all possible worlds, so it is necessarily true (□P) or not possibly false (~◊~P).

All modal systems have a number of controversial implications, and there is not space to review them here. Here we need only note that modal logic is a type of formal reasoning that increases the power of propositional logic to capture more of what we attempt to express in natural languages. (For more, see “ Modal Logic: A Contemporary View .”)

d. Predicate Logic

Predicate logic, in particular, first-order predicate logic, is even more powerful than propositional logic. Whereas propositional logic treats propositions as atomic wholes, predicate logic allows reasoners to identify and refer to subjects of propositions, independently of their predicates. For instance, whereas the proposition, “Susan is witty,” would be replaced with a single upper-case letter, say “S,” in propositional logic, predicate logic would assign the subject “Susan” a lower-case letter, s, and the predicate “is witty” an upper-case letter, W, and the translation (or formula ) would be: Ws.

In addition to distinguishing subjects and predicates, first-order predicate logic allows reasoners to quantify over subjects. The quantifiers in predicate logic are “All…,” which is comparable to “All” quantifier in categorical logic and is sometimes symbolized with an upside-down A: ∀ (though it may not be symbolized at all), and “There is at least one…,” which is comparable to “Some” quantifier in categorical logic and is symbolized with a backward E: ∃. E and O claims are formed by employing the negation operator from propositional logic. In this formal system, the proposition, “Someone is witty,” for example, has the form: There is an x , such that x has the property of being witty, which is symbolized: (∃ x)(Wx). Similarly, the proposition, “Everyone is witty,” has the form: For all x, x has the property of being witty, which is symbolized (∀ x )( Wx ) or, without the ∀: ( x )( Wx ).

Predicate derivations are conducted according to the same rules of inference and replacement as propositional logic with the exception of four rules to accommodate adding and eliminating quantifiers.

Second-order predicate logic extends first-order predicate logic to allow critical thinkers to quantify over and draw inferences about subjects and predicates, including relations among subjects and predicates. In both first- and second-order logic, predicates typically take the form of properties (one-place predicates) or relations (two-place predicates), though there is no upper limit on place numbers. Second-order logic allows us to treat both as falling under quantifiers, such as e verything that is (specifically, that has the property of being) a tea cup and everything that is a bachelor is unmarried .

e. Other Formal Systems

It is worth noting here that the formal reasoning systems we have seen thus far (categorical, propositional, and predicate) all presuppose that truth is bivalent , that is, two-valued. The two values critical thinkers are most often concerned with are true and false , but any bivalent system is subject to the rules of inference and replacement of propositional logic. The most common alternative to truth values is the binary code of 1s and 0s used in computer programming. All logics that presuppose bivalence are called classical logics . In the next section, we see that not all formal systems are bivalent; there are non-classical logics . The existence of non-classical systems raises interesting philosophical questions about the nature of truth and the legitimacy of our basic rules of reasoning, but these questions are too far afield for this context. Many philosophers regard bivalent systems as legitimate for all but the most abstract and purely formal contexts. Included below is a brief description of three of the most common non-classical logics.

Tense logic , or temporal logic, is a formal modal system developed by Arthur Prior (1957, 1967, 1968) to accommodate propositional language about time. For example, in addition to standard propositional operators, tense logic includes four operators for indexing times: P “It has at some time been the case that…”; F “It will at some time be the case that…”; H “It has always been the case that…”; and G “It will always be the case that….”

Many-valued logic , or n -valued logic, is a family of formal logical systems that attempts to accommodate intuitions that suggest some propositions have values in addition to true and false. These are often motivated by intuitions that some propositions have neither of the classic truth values; their truth value is indeterminate (not just undeterminable, but neither true nor false), for example, propositions about the future such as, “There will be a sea battle tomorrow.” If the future does not yet exist, there is no fact about the future, and therefore, nothing for a proposition to express.

Fuzzy logic is a type of many-valued logic developed out of Lotfi Zadeh’s (1965) work on mathematical sets. Fuzzy logic attempts to accommodate intuitions that suggest some propositions have truth value in degrees, that is, some degree of truth between true and false. It is motivated by concerns about vagueness in reality, for example whether a certain color is red or some degree of red, or whether some temperature is hot or some degree of hotness.

Formal reasoning plays an important role in critical thinking, but not very often. There are significant limits to how we might use formal tools in our daily lives. If that is true, how do critical thinkers reason well when formal reasoning cannot help? That brings us to informal reasoning.

4. Informal Reasoning

Informal reasoning is inductive , which means that a proposition is inferred (but not derived) from one or more propositions on the basis of the strength provided by the premises (where “strength” means some degree of likelihood less than certainty or some degree of probability less than 1 but greater than 0; a proposition with 0% probability is necessarily false).

Particular premises grant strength to premises to the degree that they reflect certain relationships or structures in the world . For instance, if a particular type of event, p , is known to cause or indicate another type of event, q , then upon encountering an event of type p , we may infer that an event of type q is likely to occur. We may express this relationship among events propositionally as follows:

• Events of type p typically cause or indicate events of type q .
• An event of type p occurred.
• Therefore, an event of type q probably occurred.

If the structure of the world (for instance, natural laws) makes premise 1 true, then, if premise 2 is true, we can reasonably (though not certainly) infer the conclusion.

Unlike formal reasoning, the adequacy of informal reasoning depends on how well the premises reflect relationships or structures in the world. And since we have not experienced every relationship among objects or events or every structure, we cannot infer with certainty that a particular conclusion follows from a true set of premises about these relationships or structures. We can only infer them to some degree of likelihood by determining to the best of our ability either their objective probability or their probability relative to alternative conclusions.

The objective probability of a conclusion refers to how likely, given the way the world is regardless of whether we know it , that conclusion is to be true. The epistemic probability of a conclusion refers to how likely that conclusion is to be true given what we know about the world , or more precisely, given our evidence for its objective likelihood.

Objective probabilities are determined by facts about the world and they are not truths of logic, so we often need evidence for objective probabilities. For instance, imagine you are about to draw a card from a standard playing deck of 52 cards. Given particular assumptions about the world (that this deck contains 52 cards and that one of them is the Ace of Spades), the objective likelihood that you will draw an Ace of Spades is 1/52. These assumptions allow us to calculate the objective probability of drawing an Ace of Spades regardless of whether we have ever drawn a card before. But these are assumptions about the world that are not guaranteed by logic: we have to actually count the cards, to be sure we count accurately and are not dreaming or hallucinating, and that our memory (once we have finished counting) reliably maintains our conclusions. None of these processes logically guarantees true beliefs. So, if our assumptions are correct, we know the objective probability of actually drawing an Ace of Spades in the real world. But since there is no logical guarantee that our assumptions are right, we are left only with the epistemic probability (the probability based on our evidence) of drawing that card. If our assumptions are right, then the objective probability is the same as our epistemic probability: 1/52. But even if we are right, objective and epistemic probabilities can come apart under some circumstances.

Imagine you draw a card without looking at it and lay it face down. What is the objective probability that that card is an Ace of Spades? The structure of the world has now settled the question, though you do not know the outcome. If it is an Ace of Spades, the objective probability is 1 (100%); it is the Ace of Spades. If it is not the Ace of Spades, the objective probability is 0 (0%); it is not the Ace of Spades. But what is the epistemic probability? Since you do not know any more about the world than you did before you drew the card, the epistemic probability is the same as before you drew it: 1/52.

Since much of the way the world is is hidden from us (like the card laid face down), and since it is not obvious that we perceive reality as it actually is (we do not know whether the actual coins we flip are evenly weighted or whether the actual dice we roll are unbiased), our conclusions about probabilities in the actual world are inevitably epistemic probabilities. We can certainly calculate objective probabilities about abstract objects (for instance, hypothetically fair coins and dice—and these calculations can be evaluated formally using probability theory and statistics), but as soon as we apply these calculations to the real world, we must accommodate the fact that our evidence is incomplete.

There are four well-established categories of informal reasoning: generalization, analogy, causal reasoning, and abduction.

a. Generalization

Generalization is a way of reasoning informally from instances of a type to a conclusion about the type. This commonly takes two forms: reasoning from a sample of a population to the whole population , and reasoning from past instances of an object or event to future instances of that object or event . The latter is sometimes called “enumerative induction” because it involves enumerating past instances of a type in order to draw an inference about a future instance. But this distinction is weak; both forms of generalization use past or current data to infer statements about future instances and whole current populations.

A popular instance of inductive generalization is the opinion poll: a sample of a population of people is polled with respect to some statement or belief. For instance, if we poll 57 sophomores enrolled at a particular college about their experiences of living in dorms, these 57 comprise our sample of the population of sophomores at that particular college. We want to be careful how we define our population given who is part of our sample. Not all college students are like sophomores, so it is not prudent to draw inferences about all college students from these sophomores. Similarly, sophomores at other colleges are not necessarily like sophomores at this college (it could be the difference between a liberal arts college and a research university), so it is prudent not to draw inferences about all sophomores from this sample at a particular college.

Let us say that 90% of the 57 sophomores we polled hate the showers in their dorms. From this information, we might generalize in the following way:

• We polled 57 sophomores at Plato’s Academy. (the sample)
• 90% of our sample hates the showers in their dorms. (the polling data)
• Therefore, probably 90% of all sophomores at Plato’s Academy hate the showers in their dorms. (a generalization from our sample to the whole population of sophomores at Plato’s Academy)

Is this good evidence that 90% of all sophomores at that college hate the showers in their dorms?

A generalization is typically regarded as a good argument if its sample is representative of its population. A sample is representative if it is similar in the relevant respects to its population. A perfectly representative sample would include the whole population: the sample would be identical with the population, and thus, perfectly representative. In that case, no generalization is necessary. But we rarely have the time or resources to evaluate whole populations. And so, a sample is generally regarded as representative if it is large relative to its population and unbiased .

In our example, whether our inference is good depends, in part, on how many sophomores there are. Are there 100, 2,000? If there are only 100, then our sample size seems adequate—we have polled over half the population. Is our sample unbiased? That depends on the composition of the sample. Is it comprised only of women or only of men? If this college is not co-ed, that is not a problem. But if the college is co-ed and we have sampled only women, our sample is biased against men. We have information only about female freshmen dorm experiences, and therefore, we cannot generalize about male freshmen dorm experiences.

How large is large enough? This is a difficult question to answer. A poll of 1% of your high school does not seem large enough to be representative. You should probably gather more data. Yet a poll of 1% of your whole country is practically impossible (you are not likely to ever have enough grant money to conduct that poll). But could a poll of less than 1% be acceptable? This question is not easily answered, even by experts in the field. The simple answer is: the more, the better. The more complicated answer is: it depends on how many other factors you can control for, such as bias and hidden variables (see §4c for more on experimental controls).

Similarly, we might ask what counts as an unbiased sample. An overly simple answer is: the sample is taken randomly, that is, by using a procedure that prevents consciously or unconsciously favoring one segment of the population over another (flipping a coin, drawing lottery balls). But reality is not simple. In political polls, it is important not to use a selection procedure that results in a sample with a larger number of members of one political party than another relative to their distribution in the population, even if the resulting sample is random. For example, the two most prominent parties in the U.S. are the Democratic Party and the Republican Party. If 47% of the U.S. is Republican and 53% is Democrat, an unbiased sample would have approximately 47% Republicans and 53% Democrats. But notice that simply choosing at random may not guarantee that result; it could easily occur, just by choosing randomly, that our sample has 70% Democrats and 30% Republicans (suppose our computer chose, albeit randomly, from a highly Democratic neighborhood). Therefore, we want to control for representativeness in some criteria, such as gender, age, and education. And we explicitly want to avoid controlling for the results we are interested in; if we controlled for particular answers to the questions on our poll, we would not learn anything—we would get all and only the answers we controlled for.

Difficulties determining representativeness suggest that reliable generalizations are not easy to construct. If we generalize on the basis of samples that are too small or if we cannot control for bias, we commit the informal fallacy of hasty generalization (see §5b). In order to generalize well, it seems we need a bit of machinery to guarantee representativeness. In fact, it seems we need an experiment, one of the primary tools in causal reasoning (see §4c below).

Argument from Analogy , also called analogical reasoning , is a way of reasoning informally about events or objects based on their similarities. A classic instance of reasoning by analogy occurs in archaeology, when researchers attempt to determine whether a stone object is an artifact (a human-made item) or simply a rock. By comparing the features of an unknown stone with well-known artifacts, archaeologists can infer whether a particular stone is an artifact. Other examples include identifying animals’ tracks by their similarities with pictures in a guidebook and consumer reports on the reliability of products.

To see how arguments from analogy work in detail, imagine two people who, independently of one another, want to buy a new pickup truck. Each chooses a make and model he or she likes, and let us say they decide on the same truck. They then visit a number of consumer reporting websites to read reports on trucks matching the features of the make and model they chose, for instance, the year it was built, the size of the engine (6 cyl. or 8 cyl.), the type of transmission (2WD or 4WD), the fuel mileage, and the cab size (standard, extended, crew). Now, let us say one of our prospective buyers is interested in safety —he or she wants a tough, safe vehicle that will protect against injuries in case of a crash. The other potential buyer is interested in mechanical reliability —he or she does not want to spend a lot of time and money fixing mechanical problems.

With this in mind, here is how our two buyers might reason analogically about whether to purchase the truck (with some fake report data included):

• The truck I have in mind was built in 2012, has a 6-cylinder engine, a 2WD transmission, and a king cab.
• 62 people who bought trucks like this one posted consumer reports and have driven it for more than a year.
• 88% of those 62 people report that the truck feels very safe.
• Therefore, the truck I am looking at will likely be very safe.
• 88% of those 62 people report that the truck has had no mechanical problems.
• Therefore, the truck I am looking at will likely have no mechanical problems.

Are the features of these analogous vehicles (the ones reported on) sufficiently numerous and relevant for helping our prospective truck buyers decide whether to purchase the truck in question (the one on the lot)? Since we have some idea that the type of engine and transmission in a vehicle contribute to its mechanical reliability, Buyer 2 may have some relevant features on which to draw a reliable analogy. Fuel mileage and cab size are not obviously relevant, but engine specifications seem to be. Are these specifications numerous enough? That depends on whether anything else that we are not aware of contributes to overall reliability. Of course, if the trucks having the features we know also have all other relevant features we do not know (if there are any), then Buyer 2 may still be able to draw a reliable inference from analogy. Of course, we do not currently know this.

Alternatively, Buyer 1 seems to have very few relevant features on which to draw a reliable analogy. The features listed are not obviously related to safety. Are there safety options a buyer may choose but that are not included in the list? For example, can a buyer choose side-curtain airbags, or do such airbags come standard in this model? Does cab size contribute to overall safety? Although there are a number of similarities between the trucks, it is not obvious that we have identified features relevant to safety or whether there are enough of them. Further, reports of “feeling safe” are not equivalent to a truck actually being safe. Better evidence would be crash test data or data from actual accidents involving this truck. This information is not likely to be on a consumer reports website.

A further difficulty is that, in many cases, it is difficult to know whether many similarities are necessary if the similarities are relevant. For instance, if having lots of room for passengers is your primary concern, then any other features are relevant only insofar as they affect cab size. The features that affect cab size may be relatively small.

This example shows that arguments from analogy are difficult to formulate well. Arguments from analogy can be good arguments when critical thinkers identify a sufficient number of features of known objects that are also relevant to the feature inferred to be shared by the object in question. If a rock is shaped like a cutting tool, has marks consistent with shaping and sharpening, and has wear marks consistent with being held in a human hand, it is likely that rock is an artifact. But not all cases are as clear.

It is often difficult to determine whether the features we have identified are sufficiently numerous or relevant to our interests. To determine whether an argument from analogy is good, a person may need to identify a causal relationship between those features and the one in which she is interested (as in the case with a vehicle’s mechanical reliability). This usually takes the form of an experiment, which we explore below (§4c).

Difficulties with constructing reliable generalizations and analogies have led critical thinkers to develop sophisticated methods for controlling for the ways these arguments can go wrong. The most common way to avoid the pitfalls of these arguments is to identify the causal structures in the world that account for or underwrite successful generalizations and analogies. Causal arguments are the primary method of controlling for extraneous causal influences and identifying relevant causes. Their development and complexity warrant regarding them as a distinct form of informal reasoning.

c. Causal Reasoning

Causal arguments attempt to draw causal conclusions (that is, statements that express propositions about causes: x causes y ) from premises about relationships among events or objects. Though it is not always possible to construct a causal argument, when available, they have an advantage over other types of inductive arguments in that they can employ mechanisms (experiments) that reduce the risks involved in generalizations and analogies.

The interest in identifying causal relationships often begins with the desire to explain correlations among events (as pollen levels increase, so do allergy symptoms) or with the desire to replicate an event (building muscle, starting a fire) or to eliminate an event (polio, head trauma in football).

Correlations among events may be positive (where each event increases at roughly the same rate) or negative (where one event decreases in proportion to another’s increase). Correlations suggest a causal relationship among the events correlated.

But we must be careful; correlations are merely suggestive—other forces may be at work. Let us say the y-axis in the charts above represents the number of millionaires in the U.S. and the x-axis represents the amount of money U.S. citizens pay for healthcare each year. Without further analysis, a positive correlation between these two may lead someone to conclude that increasing wealth causes people to be more health conscious and to seek medical treatment more often. A negative correlation may lead someone to conclude that wealth makes people healthier and, therefore, that they need to seek medical care less frequently.

Unfortunately, correlations can occur without any causal structures (mere coincidence) or because of a third, as-yet-unidentified event (a cause common to both events, or “common cause”), or the causal relationship may flow in an unexpected direction (what seems like the cause is really the effect). In order to determine precisely which event (if any) is responsible for the correlation, reasoners must eliminate possible influences on the correlation by “controlling” for possible influences on the relationship (variables).

Critical thinking about causes begins by constructing hypotheses about the origins of particular events. A hypothesis is an explanation or event that would account for the event in question. For example, if the question is how to account for increased acne during adolescence, and we are not aware of the existence of hormones, we might formulate a number of hypotheses about why this happens: during adolescence, people’s diets change (parents no longer dictate their meals), so perhaps some types of food cause acne; during adolescence, people become increasingly anxious about how they appear to others, so perhaps anxiety or stress causes acne; and so on.

After we have formulated a hypothesis, we identify a test implication that will help us determine whether our hypothesis is correct. For instance, if some types of food cause acne, we might choose a particular food, say, chocolate, and say: if chocolate causes acne (hypothesis), then decreasing chocolate will decrease acne (test implication). We then conduct an experiment to see whether our test implication occurs.

Reasoning about our experiment would then look like one of the following arguments:

There are a couple of important things to note about these arguments. First, despite appearances, both are inductive arguments. The one on the left commits the formal fallacy of affirming the consequent, so, at best, the premises confer only some degree of probability on the conclusion. The argument on the right looks to be deductive (on the face of it, it has the valid form modus tollens ), but it would be inappropriate to regard it deductively. This is because we are not evaluating a logical connection between H and TI, we are evaluating a causal connection—TI might be true or false regardless of H (we might have chosen an inappropriate test implication or simply gotten lucky), and therefore, we cannot conclude with certainty that H does not causally influence TI. Therefore, “If…, then…” statements in experiments must be read as causal conditionals and not material conditionals (the term for how we used conditionals above).

Second, experiments can go wrong in many ways, so no single experiment will grant a high degree of probability to its causal conclusion. Experiments may be biased by hidden variables (causes we did not consider or detect, such as age, diet, medical history, or lifestyle), auxiliary assumptions (the theoretical assumptions by which evaluating the results may be faulty), or underdetermination (there may be a number of hypotheses consistent with those results; for example, if it is actually sugar that causes acne, then chocolate bars, ice cream, candy, and sodas would yield the same test results). Because of this, experiments either confirm or disconfirm a hypothesis; that is, they give us some reason (but not a particularly strong reason) to believe our hypothesized causes are or are not the causes of our test implications, and therefore, of our observations (see Quine and Ullian, 1978). Because of this, experiments must be conducted many times, and only after we have a number of confirming or disconfirming results can we draw a strong inductive conclusion. (For more, see “ Confirmation and Induction .”)

Experiments may be formal or informal . In formal experiments, critical thinkers exert explicit control over experimental conditions: experimenters choose participants, include or exclude certain variables, and identify or introduce hypothesized events. Test subjects are selected according to control criteria (criteria that may affect the results and, therefore, that we want to mitigate, such as age, diet, and lifestyle) and divided into control groups (groups where the hypothesized cause is absent) and experimental groups (groups where the hypothesized cause is present, either because it is introduced or selected for).

Subjects are then placed in experimental conditions. For instance, in a randomized study, the control group receives a placebo (an inert medium) whereas the experimental group receives the hypothesized cause—the putative cause is introduced, the groups are observed, and the results are recorded and compared. When a hypothesized cause is dangerous (such as smoking) or its effects potentially irreversible (for instance, post-traumatic stress disorder), the experimental design must be restricted to selecting for the hypothesized cause already present in subjects, for example, in retrospective (backward-looking) and prospective (forward-looking) studies. In all types of formal experiments, subjects are observed under exposure to the test or placebo conditions for a specified time, and results are recorded and compared.

In informal experiments, critical thinkers do not have access to sophisticated equipment or facilities and, therefore, cannot exert explicit control over experimental conditions. They are left to make considered judgments about variables. The most common informal experiments are John Stuart Mill’s five methods of inductive reasoning, called Mill’s Methods, which he first formulated in A System of Logic (1843). Here is a very brief summary of Mill’s five methods:

(1) The Method of Agreement

If all conditions containing the event y also contain x , x is probably the cause of y .

For example:

“I’ve eaten from the same box of cereal every day this week, but all the times I got sick after eating cereal were times when I added strawberries. Therefore, the strawberries must be bad.”

(2) The Method of Difference

If all conditions lacking y also lack x , x is probably the cause of y .

“The organization turned all its tax forms in on time for years, that is, until our comptroller, George, left; after that, we were always late. Only after George left were we late. Therefore, George was probably responsible for getting our tax forms in on time.”

(3) The Joint Method of Agreement and Difference

If all conditions containing event y also contain event x , and all events lacking y also lack x , x is probably the cause of y .

“The conditions at the animal shelter have been pretty regular, except we had a string of about four months last year when the dogs barked all night, every night. But at the beginning of those four months we sheltered a redbone coonhound, and the barking stopped right after a family adopted her. All the times the redbone hound wasn’t present, there was no barking. Only the time she was present was there barking. Therefore, she probably incited all the other dogs to bark.”

(4) The Method of Concomitant Variation

If the frequency of event y increases and decreases as event x increases and decreases, respectively, x is probably the cause of y .

“We can predict the amount of alcohol sales by the rate of unemployment. As unemployment rises, so do alcohol sales. As unemployment drops, so do alcohol sales. Last quarter marked the highest unemployment in three years, and our sales last quarter are the highest they had been in those three years. Therefore, unemployment probably causes people to buy alcohol.”

(5) The Method of Residues

If a number of factors x , y , and z , may be responsible for a set of events A , B , and C , and if we discover reasons for thinking that x is the cause of A and y is the cause of B , then we have reason to believe z is the cause of C .

“The people who come through this medical facility are usually starving and have malaria, and a few have polio. We are particularly interested in treating the polio. Take this patient here: she is emaciated, which is caused by starvation; and she has a fever, which is caused by malaria. But notice that her muscles are deteriorating, and her bones are sore. This suggests she also has polio.”

d. Abduction

Not all inductive reasoning is inferential. In some cases, an explanation is needed before we can even begin drawing inferences. Consider Darwin’s idea of natural selection. Natural selection is not an object, like a blood vessel or a cellular wall, and it is not, strictly speaking, a single event. It cannot be detected in individual organisms or observed in a generation of offspring. Natural selection is an explanation of biodiversity that combines the process of heritable variation and environmental pressures to account for biomorphic change over long periods of time. With this explanation in hand, we can begin to draw some inferences. For instance, we can separate members of a single species of fruit flies, allow them to reproduce for several generations, and then observe whether the offspring of the two groups can reproduce. If we discover they cannot reproduce, this is likely due to certain mutations in their body types that prevent them from procreating. And since this is something we would expect if natural selection were true, we have one piece of confirming evidence for natural selection. But how do we know the explanations we come up with are worth our time?

Coined by C. S. Peirce (1839-1914), abduction , also called retroduction, or inference to the best explanation , refers to a way of reasoning informally that provides guidelines for evaluating explanations. Rather than appealing to types of arguments (generalization, analogy, causation), the value of an explanation depends on the theoretical virtues it exemplifies. A theoretical virtue is a quality that renders an explanation more or less fitting as an account of some event. What constitutes fittingness (or “loveliness,” as Peter Lipton (2004) calls it) is controversial, but many of the virtues are intuitively compelling, and abduction is a widely accepted tool of critical thinking.

The most widely recognized theoretical virtue is probably simplicity , historically associated with William of Ockham (1288-1347) and known as Ockham’s Razor . A legend has it that Ockham was asked whether his arguments for God’s existence prove that only one God exists or whether they allow for the possibility that many gods exist. He supposedly responded, “Do not multiply entities beyond necessity.” Though this claim is not found in his writings, Ockham is now famous for advocating that we restrict our beliefs about what is true to only what is absolutely necessary for explaining what we observe.

In contemporary theoretical use, the virtue of simplicity is invoked to encourage caution in how many mechanisms we introduce to explain an event. For example, if natural selection can explain the origin of biological diversity by itself, there is no need to hypothesize both natural selection and a divine designer. But if natural selection cannot explain the origin of, say, the duck-billed platypus, then some other mechanism must be introduced. Of course, not just any mechanism will do. It would not suffice to say the duck-billed platypus is explained by natural selection plus gremlins. Just why this is the case depends on other theoretical virtues; ideally, the virtues work together to help critical thinkers decide among competing hypotheses to test. Here is a brief sketch of some other theoretical virtues or ideals:

Conservatism – a good explanation does not contradict well-established views in a field.

Independent Testability – a good explanation is successful on different occasions under similar circumstances.

Fecundity – a good explanation leads to results that make even more research possible.

Explanatory Depth – a good explanation provides details of how an event occurs.

Explanatory Breadth – a good explanation also explains other, similar events.

Though abduction is structurally distinct from other inductive arguments, it functions similarly in practice: a good explanation provides a probabilistic reason to believe a proposition. This is why it is included here as a species of inductive reasoning. It might be thought that explanations only function to help critical thinkers formulate hypotheses, and do not, strictly speaking, support propositions. But there are intuitive examples of explanations that support propositions independently of however else they may be used. For example, a critical thinker may argue that material objects exist outside our minds is a better explanation of why we perceive what we do (and therefore, a reason to believe it) than that an evil demon is deceiving me , even if there is no inductive or deductive argument sufficient for believing that the latter is false. (For more, see “ Charles Sanders Peirce: Logic .”)

5. Detecting Poor Reasoning

Our attempts at thinking critically often go wrong, whether we are formulating our own arguments or evaluating the arguments of others. Sometimes it is in our interests for our reasoning to go wrong, such as when we would prefer someone to agree with us than to discover the truth value of a proposition. Other times it is not in our interests; we are genuinely interested in the truth, but we have unwittingly made a mistake in inferring one proposition from others. Whether our errors in reasoning are intentional or unintentional, such errors are called fallacies (from the Latin, fallax, which means “deceptive”). Recognizing and avoiding fallacies helps prevent critical thinkers from forming or maintaining defective beliefs.

Fallacies occur in a number of ways. An argument’s form may seem to us valid when it is not, resulting in a formal fallacy . Alternatively, an argument’s premises may seem to support its conclusion strongly but, due to some subtlety of meaning, do not, resulting in an informal fallacy . Additionally, some of our errors may be due to unconscious reasoning processes that may have been helpful in our evolutionary history, but do not function reliably in higher order reasoning. These unconscious reasoning processes are now widely known as heuristics and biases . Each type is briefly explained below.

a. Formal Fallacies

Formal fallacies occur when the form of an argument is presumed or seems to be valid (whether intentionally or unintentionally) when it is not. Formal fallacies are usually invalid variations of valid argument forms. Consider, for example, the valid argument form modus ponens (this is one of the rules of inference mentioned in §3b):

modus ponens (valid argument form)

In modus ponens , we assume or “affirm” both the conditional and the left half of the conditional (called the antecedent ): (p à q) and p. From these, we can infer that q, the second half or consequent , is true. This a valid argument form: if the premises are true, the conclusion cannot be false.

Sometimes, however, we invert the conclusion and the second premise, affirming that the conditional, (p à q), and the right half of the conditional, q (the consequent), are true, and then inferring that the left half, p (the antecedent), is true. Note in the example below how the conclusion and second premise are switched. Switching them in this way creates a problem.

To get an intuitive sense of why “affirming the consequent” is a problem, consider this simple example:

affirming the consequent

• It is a mammal.
• Therefore, it is a cat.(?)

From the fact that something is a mammal, we cannot conclude that it is a cat. It may be a dog or a mouse or a whale. The premises can be true and yet the conclusion can still be false. Therefore, this is not a valid argument form. But since it is an easy mistake to make, it is included in the set of common formal fallacies.

Here is a second example with the rule of inference called modus tollens . Modus tollens involves affirming a conditional, (p à q), and denying that conditional’s consequent: ~q. From these two premises, we can validly infer the denial of the antecedent: ~p. But if we switch the conclusion and the second premise, we get another fallacy, called denying the antecedent .

Technically, all informal reasoning is formally fallacious—all informal arguments are invalid. Nevertheless, since those who offer inductive arguments rarely presume they are valid, we do not regard them as reasoning fallaciously.

b. Informal Fallacies

Informal fallacies occur when the meaning of the terms used in the premises of an argument suggest a conclusion that does not actually follow from them (the conclusion either follows weakly or with no strength at all). Consider an example of the informal fallacy of equivocation , in which a word with two distinct meanings is used in both of its meanings:

• Any law can be repealed by Congress.
• Gravity is a law.
• Therefore, gravity can be repealed by Congress.

In this case, the argument’s premises are true when the word “law” is rightly interpreted, but the conclusion does not follow because the word law has a different referent in premise 1 (political laws) than in premise 2 (a law of nature). This argument equivocates on the meaning of law and is, therefore, fallacious.

Consider, also, the informal fallacy of ad hominem , abusive, when an arguer appeals to a person’s character as a reason to reject her proposition:

“Elizabeth argues that humans do not have souls; they are simply material beings. But Elizabeth is a terrible person and often talks down to children and the elderly. Therefore, she could not be right that humans do not have souls.”

The argument might look like this:

• Elizabeth is a terrible person and often talks down to children and the elderly.
• Therefore, Elizabeth is not right that humans do not have souls.

The conclusion does not follow because whether Elizabeth is a terrible person is irrelevant to the truth of the proposition that humans do not have souls. Elizabeth’s argument for this statement is relevant, but her character is not.

Another way to evaluate this fallacy is to note that, as the argument stands, it is an enthymeme (see §2); it is missing a crucial premise, namely: If anyone is a terrible person, that person makes false statements. But this premise is clearly false. There are many ways in which one can be a terrible person, and not all of them imply that someone makes false statements. (In fact, someone could be terrible precisely because they are viciously honest.) Once we fill in the missing premise, we see the argument is not cogent because at least one premise is false.

Importantly, we face a number of informal fallacies on a daily basis, and without the ability to recognize them, their regularity can make them seem legitimate. Here are three others that only scratch the surface:

Appeal to the People: We are often encouraged to believe or do something just because everyone else does. We are encouraged to believe what our political party believes, what the people in our churches or synagogues or mosques believe, what people in our family believe, and so on. We are encouraged to buy things because they are “bestsellers” (lots of people buy them). But the fact that lots of people believe or do something is not, on its own, a reason to believe or do what they do.

Tu Quoque (You, too!): We are often discouraged from pursuing a conclusion or action if our own beliefs or actions are inconsistent with them. For instance, if someone attempts to argue that everyone should stop smoking, but that person smokes, their argument is often given less weight: “Well, you smoke! Why should everyone else quit?” But the fact that someone believes or does something inconsistent with what they advocate does not, by itself, discredit the argument. Hypocrites may have very strong arguments despite their personal inconsistencies.

Base Rate Neglect: It is easy to look at what happens after we do something or enact a policy and conclude that the act or policy caused those effects. Consider a law reducing speed limits from 75 mph to 55 mph in order to reduce highway accidents. And, in fact, in the three years after the reduction, highway accidents dropped 30%! This seems like a direct effect of the reduction. However, this is not the whole story. Imagine you looked back at the three years prior to the law and discovered that accidents had dropped 30% over that time, too. If that happened, it might not actually be the law that caused the reduction in accidents. The law did not change the trend in accident reduction. If we only look at the evidence after the law, we are neglecting the rate at which the event occurred without the law. The base rate of an event is the rate that the event occurs without the potential cause under consideration. To take another example, imagine you start taking cold medicine, and your cold goes away in a week. Did the cold medicine cause your cold to go away? That depends on how long colds normally last and when you took the medicine. In order to determine whether a potential cause had the effect you suspect, do not neglect to compare its putative effects with the effects observed without that cause.

For more on formal and informal fallacies and over 200 different types with examples, see “ Fallacies .”

c. Heuristics and Biases

In the 1960s, psychologists began to suspect there is more to human reasoning than conscious inference. Daniel Kahneman and Amos Tversky confirmed these suspicions with their discoveries that many of the standard assumptions about how humans reason in practice are unjustified. In fact, humans regularly violate these standard assumptions, the most significant for philosophers and economists being that humans are fairly good at calculating the costs and benefits of their behavior; that is, they naturally reason according to the dictates of Expected Utility Theory. Kahneman and Tversky showed that, in practice, reasoning is affected by many non-rational influences, such as the wording used to frame scenarios (framing bias) and information most vividly available to them (the availability heuristic).

Consider the difference in your belief about the likelihood of getting robbed before and after seeing a news report about a recent robbery, or the difference in your belief about whether you will be bitten by a shark the week before and after Discovery Channel’s “Shark Week.” For most of us, we are likely to regard their likelihood as higher after we have seen these things on television than before. Objectively, they are no more or less likely to happen regardless of our seeing them on television, but we perceive they are more likely because their possibility is more vivid to us. These are examples of the availability heuristic.

Since the 1960s, experimental psychologists and economists have conducted extensive research revealing dozens of these unconscious reasoning processes, including ordering bias , the representativeness heuristic , confirmation bias , attentional bias , and the anchoring effect . The field of behavioral economics, made popular by Dan Ariely (2008; 2010; 2012) and Richard Thaler and Cass Sunstein (2009), emerged from and contributes to heuristics and biases research and applies its insights to social and economic behaviors.

Ideally, recognizing and understanding these unconscious, non-rational reasoning processes will help us mitigate their undermining influence on our reasoning abilities (Gigerenzer, 2003). However, it is unclear whether we can simply choose to overcome them or whether we have to construct mechanisms that mitigate their influence (for instance, using double-blind experiments to prevent confirmation bias).

6. The Scope and Virtues of Good Reasoning

Whether the process of critical thinking is productive for reasoners—that is, whether it actually answers the questions they are interested in answering—often depends on a number of linguistic, psychological, and social factors. We encountered some of the linguistic factors in §1. In closing, let us consider some of the psychological and social factors that affect the success of applying the tools of critical thinking.

Not all psychological and social contexts are conducive for effective critical thinking. When reasoners are depressed or sad or otherwise emotionally overwhelmed, critical thinking can often be unproductive or counterproductive. For instance, if someone’s child has just died, it would be unproductive (not to mention cruel) to press the philosophical question of why a good God would permit innocents to suffer or whether the child might possibly have a soul that could persist beyond death. Other instances need not be so extreme to make the same point: your company’s holiday party (where most people would rather remain cordial and superficial) is probably not the most productive context in which to debate the president’s domestic policy or the morality of abortion.

The process of critical thinking is primarily about detecting truth, and truth may not always be of paramount value. In some cases, comfort or usefulness may take precedence over truth. The case of the loss of a child is a case where comfort seems to take precedence over truth. Similarly, consider the case of determining what the speed limit should be on interstate highways. Imagine we are trying to decide whether it is better to allow drivers to travel at 75 mph or to restrict them to 65. To be sure, there may be no fact of the matter as to which is morally better, and there may not be any difference in the rate of interstate deaths between states that set the limit at 65 and those that set it at 75. But given the nature of the law, a decision about which speed limit to set must be made. If there is no relevant difference between setting the limit at 65 and setting it at 75, critical thinking can only tell us that , not which speed limit to set. This shows that, in some cases, concern with truth gives way to practical or preferential concerns (for example, Should I make this decision on the basis of what will make citizens happy? Should I base it on whether I will receive more campaign contributions from the business community?). All of this suggests that critical thinking is most productive in contexts where participants are already interested in truth.

b. The Principle of Charity/Humility

Critical thinking is also most productive when people in the conversation regard themselves as fallible, subject to error, misinformation, and deception. The desire to be “right” has a powerful influence on our reasoning behavior. It is so strong that our minds bias us in favor of the beliefs we already hold even in the face of disconfirming evidence (a phenomenon known as “confirmation bias”). In his famous article, “The Ethics of Belief” (1878), W. K. Clifford notes that, “We feel much happier and more secure when we think we know precisely what to do, no matter what happens, than when we have lost our way and do not know where to turn. … It is the sense of power attached to a sense of knowing that makes men desirous of believing, and afraid of doubting” (2010: 354).

Nevertheless, when we are open to the possibility that we are wrong, that is, if we are humble about our conclusions and we interpret others charitably, we have a better chance at having rational beliefs in two senses. First, if we are genuinely willing to consider evidence that we are wrong—and we demonstrate that humility—then we are more likely to listen to others when they raise arguments against our beliefs. If we are certain we are right, there would be little reason to consider contrary evidence. But if we are willing to hear it, we may discover that we really are wrong and give up faulty beliefs for more reasonable ones.

Second, if we are willing to be charitable to arguments against our beliefs, then if our beliefs are unreasonable, we have an opportunity to see the ways in which they are unreasonable. On the other hand, if our beliefs are reasonable, then we can explain more effectively just how well they stand against the criticism. This is weakly analogous to competition in certain types of sporting events, such as basketball. If you only play teams that are far inferior to your own, you do not know how good your team really is. But if you can beat a well-respected team on fair terms, any confidence you have is justified.

c. The Principle of Caution

In our excitement over good arguments, it is easy to overextend our conclusions, that is, to infer statements that are not really warranted by our evidence. From an argument for a first, uncaused cause of the universe, it is tempting to infer the existence of a sophisticated deity such as that of the Judeo-Christian tradition. From an argument for the compatibilism of the free will necessary for moral responsibility and determinism, it is tempting to infer that we are actually morally responsible for our behaviors. From an argument for negative natural rights, it is tempting to infer that no violation of a natural right is justifiable. Therefore, it is prudent to continually check our conclusions to be sure they do not include more content than our premises allow us to infer.

Of course, the principle of caution must itself be used with caution. If applied too strictly, it may lead reasoners to suspend all belief, and refrain from interacting with one another and their world. This is not, strictly speaking, problematic; ancient skeptics, such as the Pyrrhonians, advocated suspending all judgments except those about appearances in hopes of experiencing tranquility. However, at least some judgments about the long-term benefits and harms seem indispensable even for tranquility, for instance, whether we should retaliate in self-defense against an attacker or whether we should try to help a loved one who is addicted to drugs or alcohol.

d. The Expansiveness of Critical Thinking

The importance of critical thinking cannot be overstated because its relevance extends into every area of life, from politics, to science, to religion, to ethics. Not only does critical thinking help us draw inferences for ourselves, it helps us identify and evaluate the assumptions behind statements, the moral implications of statements, and the ideologies to which some statements commit us. This can be a disquieting and difficult process because it forces us to wrestle with preconceptions that might not be accurate. Nevertheless, if the process is conducted well, it can open new opportunities for dialogue, sometimes called “critical spaces,” that allow people who might otherwise disagree to find beliefs in common from which to engage in a more productive conversation.

It is this possibility of creating critical spaces that allows philosophical approaches like Critical Theory to effectively challenge the way social, political, and philosophical debates are framed. For example, if a discussion about race or gender or sexuality or gender is framed in terms that, because of the origins those terms or the way they have functioned socially, alienate or disproportionately exclude certain members of the population, then critical space is necessary for being able to evaluate that framing so that a more productive dialogue can occur (see Foresman, Fosl, and Watson, 2010, ch. 10 for more on how critical thinking and Critical Theory can be mutually supportive).

e. Productivity and the Limits of Rationality

Despite the fact that critical thinking extends into every area of life, not every important aspect of our lives is easily or productively subjected to the tools of language and logic. Thinkers who are tempted to subject everything to the cold light of reason may discover they miss some of what is deeply enjoyable about living. The psychologist Abraham Maslow writes, “I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail” (1966: 16). But it is helpful to remember that language and logic are tools, not the projects themselves. Even formal reasoning systems depend on axioms that are not provable within their own systems (consider Euclidean geometry or Peano arithmetic). We must make some decisions about what beliefs to accept and how to live our lives on the basis of considerations outside of critical thinking.

Borrowing an example from William James (1896), consider the statement, “Religion X is true.” James says that, while some people find this statement interesting, and therefore, worth thinking critically about, others may not be able to consider the truth of the statement. For any particular religious tradition, we might not know enough about it to form a belief one way or the other, and even suspending judgment may be difficult, since it is not obvious what we are suspending judgment about.

If I say to you: ‘Be a theosophist or be a Mohammedan,’ it is probably a dead option, because for you neither hypothesis is likely to be alive. But if I say: ‘Be an agnostic or be a Christian,’ it is otherwise: trained as you are, each hypothesis makes some appeal, however small, to your belief (2010: 357).

Ignoring the circularity in his definition of “dead option,” James’s point seems to be that if you know nothing about a view or what statements it entails, no amount of logic or evidence could help you form a reasonable belief about that position.

We might criticize James at this point because his conclusion seems to imply that we have no duty to investigate dead options, that is, to discover if there is anything worth considering in them. If we are concerned with truth, the simple fact that we are not familiar with a proposition does not mean it is not true or potentially significant for us. But James’s argument is subtler than this criticism suggests. Even if you came to learn about a particularly foreign religious tradition, its tenets may be so contrary to your understanding of the world that you could not entertain them as possible beliefs of yours . For instance, you know perfectly well that, if some events had been different, Hitler would not have existed: his parents might have had no children, or his parents’ parents might have had no children. You know roughly what it would mean for Hitler not to have existed and the sort of events that could have made it true that he did not exist. But how much evidence would it take to convince you that, in fact, Hitler did not exist, that is, that your belief that Hitler did exist is false ? Could there be an argument strong enough? Not obviously. Since all the information we have about Hitler unequivocally points to his existence, any arguments against that belief would have to affect a very broad range of statements; they would have to be strong enough to make us skeptical of large parts of reality.

7. Approaches to Improving Reasoning through Critical Thinking

Recall that the goal of critical thinking is not just to study what makes reasons and statements good, but to help us improve our ability to reason, that is, to improve our ability to form, hold, and discard beliefs according to whether they meet the standards of good thinking. Some ways of approaching this latter goal are more effective than others. While the classical approach focuses on technical reasoning skills, the Paul/Elder model encourages us to think in terms of critical concepts, and irrationality approaches use empirical research on instances of poor reasoning to help us improve reasoning where it is least obvious we need it and where we need it most. Which approach or combination of approaches is most effective depends, as noted above, on the context and limits of critical thinking, but also on scientific evidence of their effectiveness. Those who teach critical thinking, of all people, should be engaged with the evidence relevant to determining which approaches are most effective.

a. Classical Approaches

The classic approach to critical thinking follows roughly the structure of this article: critical thinkers attempt to interpret statements or arguments clearly and charitably, and then they apply the tools of formal and informal logic and science, while carefully attempting to avoid fallacious inferences (see Weston, 2008; Walton, 2008; Watson and Arp, 2015). This approach requires spending extensive time learning and practicing technical reasoning strategies. It presupposes that reasoning is primarily a conscious activity, and that enhancing our skills in these areas will improve our ability to reason well in ordinary situations.

There are at least two concerns about this approach. First, it is highly time intensive relative to its payoff. Learning the terminology of systems like propositional and categorical logic and the names of the fallacies, and practicing applying these tools to hypothetical cases requires significant time and energy. And it is not obvious, given the problems with heuristics and biases, whether this practice alone makes us better reasoners in ordinary contexts. Second, many of the ways we reason poorly are not consciously accessible (recall the heuristics and biases discussion in §5c). Our biases, combined with the heuristics we rely on in ordinary situations, can only be detected in experimental settings, and addressing them requires restructuring the ways in which we engage with evidence (see Thaler and Sunstein, 2009).

b. The Paul/Elder Model

Richard Paul and Linda Elder (Paul and Elder, 2006; Paul, 2012) developed an alternative to the classical approach on the assumption that critical thinking is not something that is limited to academic study or to the discipline of philosophy. On their account, critical thinking is a broad set of conceptual skills and habits aimed at a set of standards that are widely regarded as virtues of thinking: clarity, accuracy, depth, fairness, and others. They define it simply as “the art of analyzing and evaluating thinking with a view to improving it” (2006: 4). Their approach, then, is to focus on the elements of thought and intellectual virtues that help us form beliefs that meet these standards.

The Paul/Elder model is made up of three sets of concepts: elements of thought, intellectual standards, and intellectual traits. In this model, we begin by identifying the features present in every act of thought. They use “thought” to mean critical thought aimed at forming beliefs, not just any act of thinking, musing, wishing, hoping, remembering. According to the model, every act of thought involves:

These comprise the subject matter of critical thinking; that is, they are what we are evaluating when we are thinking critically. We then engage with this subject matter by subjecting them to what Paul and Elder call universal intellectual standards. These are evaluative goals we should be aiming at with our thinking:

While in classical approaches, logic is the predominant means of thinking critically, in the Paul/Elder model, it is put on equal footing with eight other standards. Finally, Paul and Elder argue that it is helpful to approach the critical thinking process with a set of intellectual traits or virtues that dispose us to using elements and standards well.

To remind us that these are virtues of thought relevant to critical thinking, they use “intellectual” to distinguish these traits from their moral counterparts (moral integrity, moral courage, and so on).

The aim is that, as we become familiar with these three sets of concepts and apply them in everyday contexts, we become better at analyzing and evaluating statements and arguments in ordinary situations.

Like the classical approach, this approach presupposes that reasoning is primarily a conscious activity, and that enhancing our skills will improve our reasoning. This means that it still lacks the ability to address the empirical evidence that many of our reasoning errors cannot be consciously detected or corrected. It differs from the classical approach in that it gives the technical tools of logic a much less prominent role and places emphasis on a broader, and perhaps more intuitive, set of conceptual tools. Learning and learning to apply these concepts still requires a great deal of time and energy, though perhaps less than learning formal and informal logic. And these concepts are easy to translate into disciplines outside philosophy. Students of history, psychology, and economics can more easily recognize the relevance of asking questions about an author’s point of view and assumptions than perhaps determining whether the author is making a deductive or inductive argument. The question, then, is whether this approach improves our ability to think better than the classical approach.

c. Other Approaches

A third approach that is becoming popular is to focus on the ways we commonly reason poorly and then attempt to correct them. This can be called the Rationality Approach , and it takes seriously the empirical evidence (§5c) that many of our errors in reasoning are not due to a lack of conscious competence with technical skills or misusing those skills, but are due to subconscious dispositions to ignore or dismiss relevant information or to rely on irrelevant information.

One way to pursue this approach is to focus on beliefs that are statistically rare or “weird.” These include beliefs of fringe groups, such as conspiracy theorists, religious extremists, paranormal psychologists, and proponents of New Age metaphysics (see Gilovich, 1992; Vaughn and Schick, 2010; Coady, 2012). If we recognize the sorts of tendencies that lead to these controversial beliefs, we might be able to recognize and avoid similar tendencies in our own reasoning about less extreme beliefs, such as beliefs about financial investing, how statistics are used to justify business decisions, and beliefs about which public policies to vote for.

Another way to pursue this approach is to focus directly on the research on error, those ordinary beliefs that psychologists and behavioral economists have discovered we reason poorly, and to explore ways of changing how we frame decisions about what to believe (see Nisbett and Ross, 1980; Gilovich, 1992; Ariely, 2008; Kahneman, 2011). For example, in one study, psychologists found that judges issue more convictions just before lunch and the end of the day than in the morning or just after lunch (Danzinger, et al., 2010). Given that dockets do not typically organize cases from less significant crimes to more significant crimes, this evidence suggests that something as irrelevant as hunger can bias judicial decisions. Even though hunger has nothing to do with the truth of a belief, knowing that it can affect how we evaluate a belief can help us avoid that effect. This study might suggest something as simple as that we should avoid being hungry when making important decisions. The more we learn ways in which our brains use irrelevant information, the better we can organize our reasoning to avoid these mistakes. For more on how decisions can be improved by restructuring our decisions, see Thaler and Sunstein, 2009.

A fourth approach is to take more seriously the role that language plays in our reasoning. Arguments involve complex patterns of expression, and we have already seen how vagueness and ambiguity can undermine good reasoning (§1). The pragma-dialectics approach (or pragma-dialectical theory) is the view that the quality of an argument is not solely or even primarily a matter of its logical structure, but is more fundamentally a matter of whether it is a form of reasonable discourse (Van Eemeren and Grootendorst, 1992). The proponents of this view contend that, “The study of argumentation should … be construed as a special branch of linguistic pragmatics in which descriptive and normative perspectives on argumentative discourse are methodically integrated” (Van Eemeren and Grootendorst, 1995: 130).

The pragma-dialectics approach is a highly technical approach that uses insights from speech act theory, H. P. Grice’s philosophy of language, and the study of discourse analysis. Its use, therefore, requires a great deal of background in philosophy and linguistics. It has an advantage over other approaches in that it highlights social and practical dimensions of arguments that other approaches largely ignore. For example, argument is often public ( external ), in that it creates an opportunity for opposition, which influences people’s motives and psychological attitudes toward their arguments. Argument is also social in that it is part of a discourse in which two or more people try to arrive at an agreement. Argument is also functional ; it aims at a resolution that can only be accommodated by addressing all the aspects of disagreement or anticipated disagreement, which can include public and social elements. Argument also has a rhetorical role ( dialectical ) in that it is aimed at actually convincing others, which may have different requirements than simply identifying the conditions under which they should be convinced.

These four approaches are not mutually exclusive. All of them presuppose, for example, the importance of inductive reasoning and scientific evidence. Their distinctions turn largely on which aspects of statements and arguments should take precedence in the critical thinking process and on what information will help us have better beliefs.

8. References and Further Reading

• Ariely, Dan. 2008. Predictably Irrational: The Hidden Forces that Shape Our Decisions. New York: Harper Perennial.
• Ariely, Dan. 2010. The Upside of Irrationality. New York: Harper Perennial.
• Ariely, Dan. 2012. The (Honest) Truth about Dishonesty. New York: Harper Perennial.
• Aristotle. 2002. Categories and De Interpretatione, J. L. Akrill, editor. Oxford: University of Oxford Press.
• Clifford, W. K. 2010. “The Ethics of Belief.” In Nils Ch. Rauhut and Robert Bass, eds., Readings on the Ultimate Questions: An Introduction to Philosophy, 3rd ed. Boston: Prentice Hall, 351-356.
• Chomsky, Noam. 1957/2002. Syntactic Structures. Berlin: Mouton de Gruyter.
• Coady, David. What To Believe Now: Applying Epistemology to Contemporary Issues. Malden, MA: Wiley-Blackwell, 2012.
• Danzinger, Shai, Jonathan Levav, and Liora Avnaim-Pesso. 2011. “Extraneous Factors in Judicial Decisions.” Proceedings of the National Academy of Sciences of the United States of America. Vol. 108, No. 17, 6889-6892. doi: 10.1073/pnas.1018033108.
• Foresman, Galen, Peter Fosl, and Jamie Carlin Watson. 2017. The Critical Thinking Toolkit. Malden, MA: Wiley-Blackwell.
• Fogelin, Robert J. and Walter Sinnott-Armstrong. 2009. Understanding Arguments: An Introduction to Informal Logic, 8th ed. Belmont, CA: Wadsworth Cengage Learning.
• Gigerenzer, Gerd. 2003. Calculated Risks: How To Know When Numbers Deceive You. New York: Simon and Schuster.
• Gigerenzer, Gerd, Peter Todd, and the ABC Research Group. 2000. Simple Heuristics that Make Us Smart. Oxford University Press.
• Gilovich, Thomas. 1992. How We Know What Isn’t So. New York: Free Press.
• James, William. “The Will to Believe”, in Nils Ch. Rauhut and Robert Bass, eds., Readings on the Ultimate Questions: An Introduction to Philosophy, 3rd ed. Boston: Prentice Hall, 2010, 356-364.
• Kahneman, Daniel. 2011. Thinking Fast and Slow. New York: Farrar, Strauss and Giroux.
• Lewis, David. 1986. On the Plurality of Worlds. Oxford Blackwell.
• Lipton, Peter. 2004. Inference to the Best Explanation, 2nd ed. London: Routledge.
• Maslow, Abraham. 1966. The Psychology of Science: A Reconnaissance. New York: Harper & Row.
• Mill, John Stuart. 2011. A System of Logic, Ratiocinative and Inductive. New York: Cambridge University Press.
• Nisbett, Richard and Lee Ross. 1980. Human Inference: Strategies and Shortcomings of Social Judgment. Englewood Cliffs, NJ: Prentice Hall.
• Paul, Richard. 2012. Critical Thinking: What Every Person Needs to Survive in a Rapidly Changing World. Tomales, CA: The Foundation for Critical Thinking.
• Paul, Richard and Linda Elder. 2006. The Miniature Guide to Critical Thinking Concepts and Tools, 4th ed. Tomales, CA: The Foundation for Critical Thinking.
• Plantinga, Alvin. 1974. The Nature of Necessity. Oxford Clarendon.
• Prior, Arthur. 1957. Time and Modality. Oxford, UK: Oxford University Press.
• Prior, Arthur. 1967. Past, Present and Future. Oxford, UK: Oxford University Press.
• Prior, Arthur. 1968. Papers on Time and Tense. Oxford, UK: Oxford University Press.
• Quine, W. V. O. and J. S. Ullian. 1978. The Web of Belief, 2nd ed. McGraw-Hill.
• Russell, Bertrand. 1940/1996. An Inquiry into Meaning and Truth, 2nd ed. London: Routledge.
• Thaler, Richard and Cass Sunstein. 2009. Nudge: Improving Decisions about Health, Wealth, and Happiness. New York: Penguin Books.
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Jamie Carlin Watson Email: [email protected] University of Arkansas for Medical Sciences U. S. A.

An encyclopedia of philosophy articles written by professional philosophers.

[A01] What is an argument?

Module: Argument analysis

• A02. The standard format
• A03. Validity
• A04. Soundness
• A05. Valid patterns
• A06. Validity and relevance
• A07. Hidden Assumptions
• A08. Inductive Reasoning
• A09. Good Arguments
• A10. Argument mapping
• A11. Analogical Arguments
• A12. More valid patterns
• A13. Arguing with other people

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A crucial part of critical thinking is to identify, construct, and evaluate arguments .

In everyday life, people often use "argument" to mean a quarrel between people. But in logic and critical thinking, an argument is a list of statements, one of which is the conclusion and the others are the premises or assumptions of the argument.

Before proceeding, read this page about statements.

To give an argument is to provide a set of premises as reasons for accepting the conclusion. To give an argument is not necessarily to attack or criticize someone. Arguments can also be used to support other people's viewpoints.

Here is an example of an argument:

If you want to find a good job, you should work hard. You do want to find a good job. So you should work hard.

The first two sentences here are the premises of the argument, and the last sentence is the conclusion. To give this argument is to offer the premises as reasons for accepting the conclusion.

A few points to note:

• Dogmatic people tend to make assertions without giving reasons. When they are criticized they often fail to give arguments to defend their own opinions.
• To improve our critical thinking skills, we should develop the habit of giving good arguments to support our opinions.
• To defend an opinion, think about whether you can give more than one argument to support it. Also, think about potential objections to your opinion, e.g. arguments against your opinion. A good thinker will consider the arguments on both sides of an issue.

See if you can give arguments to support some of your beliefs.

• For example, do you think the economy is going to improve or worsen in the next six months? Why or why not? What arguments can you give to support your position?
• Or think about something different, do you think computers can have emotions? Again, what arguments can you give to support your viewpoint? Make sure that your arguments are composed of statements.

§1. How to look for arguments

How do we identify arguments in real life? There are no easy mechanical rules, and we usually have to rely on the context in order to determine which are the premises and the conclusions. But sometimes the job can be made easier by the presence of certain premise or conclusion indicators. For example, if a person makes a statement, and then adds "this is because ...", then it is quite likely that the first statement is presented as a conclusion, supported by the statements that come afterwards. Other words in English that might be used to indicate the premises to follow include :

• firstly, secondly, ...
• for, as, after all,
• assuming that, in view of the fact that
• follows from, as shown / indicated by
• may be inferred / deduced / derived from

Of course whether such words are used to indicate premises or not depends on the context. For example, "since" has a very different function in a statement like "I have been here since noon", unlike "X is an even number since X is divisible by 4".

Conclusions, on the other hand, are often preceded by words like:

• therefore, so, it follows that
• hence, consequently
• suggests / proves / demonstrates that
• entails, implies

When people sweat a lot they tend to drink more water. [Just a single statement, not enough to make an argument.]

Once upon a time there was a prince and a princess. They lived happily together and one day they decided to have a baby. But the baby grew up to be a nasty and cruel person and they regret it very much. [A chronological description of facts composed of statements but no premise or conclusion.]

Can you come to the meeting tomorrow? [A question that does not contain an argument.]

Do these passages contain arguments? If so, what are their conclusions?

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9 The Concept of an Argument

David hitchcock, 1. introduction [1] , [2].

The concept of an argument for which I propose an analysis is the reason-giving sense in which one speaks, for example, about Daniel Kahneman’s argument (2011, pp. 334-335) that the tendency of most people to be risk averse about gains but risk-seeking about losses is irrational. This sense of the word ‘argument’ should be sharply distinguished from the disputational sense in which one speaks about two people having an argument, discussed in Chapter 8. That these are two different senses is clear from the fact that languages other than English use two different words for the two senses. For example, in French, ‘to argue’ in the sense of quarrelling is ‘ disputer ’, whereas ‘to argue’ in the sense of giving reasons for or against is ‘ argumenter ’.

We could give a rough lexical definition of the word ‘argument’ in this sense by quoting the definition by the Hellenistic Stoics of an argument as “a system composed of premisses [3] and a conclusion” ( systêma ek lêmmatôn kai epiphoras , Diogenes Laertius 1925/ca. 210-240, 7.45). Aside from its idiosyncratic failure to recognize one-premiss arguments, this definition is an acceptable starting point for a conceptual analysis. That analysis would need to answer a number of questions raised by the lexical definition. What is a premiss? What is a conclusion? What sorts of entities can function as a premiss? What sorts can function as a conclusion? How do premisses and a conclusion form a unified system? Does such a system have an intrinsic function or purpose, or on the contrary can it be used for various purposes? What about complex arguments?

We should recognize that arguments are not necessarily the content or product of argumentation—that is, of communications in which arguments are exchanged. One can consider an argument for a certain position or policy even if nobody has ever used that argument. One can imagine crazy arguments that no sane person would ever put forward. One can apply the term ‘argument’ to unified stretches of solo reasoning where some conclusion is reached on the basis of reasons, as when one considers mentally various aspects of a situation and then describes “the argument that finally convinced me”. Indeed, it seems consistent with our ordinary use of the term ‘argument’ in its reason-giving sense to say that there are arguments that nobody has ever thought of and nobody ever will. The most we can demand is that an argument must be thinkable and expressible. Arguments as a class thus have no common function or purpose. They are not necessarily used to justify or establish something. Nor are they necessarily used to persuade anybody.

Thus, critical thinking textbooks that define ‘argument’ as “rational persuasion—an attempt to influence another or others using reasons” are actually describing one use of arguments, not the concept itself.

2. Simple arguments

Begin by considering simple arguments, in the sense of single-inference systems that consist of one or more premisses and one conclusion. Of what sorts of entities are such arguments composed? That is, what kind of object can function as a premiss, and what kind can function as a conclusion? A common answer is that these components are propositions, in the sense of postulated timeless and non-located entities that can be expressed linguistically (or in some other way) and that can be objects of belief or knowledge. Propositions however are not the right candidates to be premisses or conclusions.

As to premisses, consider the following two arguments:

(1)  Suppose that there is life on other planets in the universe. Then it makes sense to look for it.

(2)  There is life on other planets in the universe. So it makes sense to look for it.

These arguments have the same conclusion, but different premisses. But both premisses express the same proposition, that there is life on other planets in the universe. The difference is in the illocutionary act performed by someone who utters the premiss in standard contexts. In uttering argument (1), the author hypothesizes the propositional content of the premiss. In uttering argument (2), on the other hand, the author asserts the proposition. The difference makes a difference to the evaluation of the two arguments: argument (2) requires a stricter condition of premiss adequacy than argument (1).

If arguments need not be expressed but their premisses are illocutionary acts, the premisses must be illocutionary act-types rather than illocutionary act-tokens. Sometimes the type may have no actual tokens. Someone can use the same argument on different occasions, and different people can use the same argument. A premiss can be a supposition or an assertive or any other member of the class of illocutionary acts that Searle (1976) grouped under the label ‘representatives’, and which he defined (p. 10) as acts whose point is to commit the speaker, perhaps hypothetically or guardedly, to something’s being the case. It cannot be any other kind of illocutionary act, as we can see by noting the peculiarity of putting examples (taken from Hitchcock 2006, pp. 103-104) of the other kinds of illocutionary acts in premissary position before an inferential ‘therefore’:

(3) * What time is it? Therefore, you must go home .

(4) ? I promise to pick up some milk on the way home. Therefore, you don’t need to get it.

(5) * Congratulations on your anniversary. Therefore, you are married.

(6) * I hereby sentence you to two years less a day. Therefore, the guards will now take you to prison.

In standard contexts, the utterances in the premissary position are respectively (3) a directive (in particular, a request for information), (4) a commissive (in particular, a promise), (5) an expressive (in particular, a congratulation), and (6) a declarative (in particular, a judicial verdict). The inappropriateness of these pairings reveal the general inability of illocutionary acts other than representatives to function as premisses. The premiss in (4) is a borderline case, because a promise can be taken to imply a prediction (that the promise will be kept) and a prediction is a kind of assertion. It is the implicit prediction rather than the commitment that makes it possible to construe example (4) as an argument.

Among conclusions, we find a greater variety of illocutionary acts than among premisses. We have already seen two examples ((1) and (2) above) in which the conclusion is a representative. Conclusions (and premisses too) can be hedged by such qualifiers as ‘probably’, ‘presumably’, ‘possibly’, and the like, which are best given a speech-act interpretation. [4] Thus a wide range of representatives can be conclusions of arguments. But the other main kinds of illocutionary acts can also be conclusions, as we can see from the following examples (taken from Hitchcock 2006, p. 105):

(7) There is a forecast of thundershowers, so let’s cancel the picnic.

(8) I know how difficult it will be for you to get the milk, so I pro m ise you that I will pick it up on the way home.

(9) My conduct was inexcusable, so I apologize most sincerely.

(10) The evidence establishes beyond a reasonable doubt that you committed the crime of which you are accused, so I hereby find you guilty as charged.

When these arguments are expressed in standard contexts, their conclusions are respectively (7) a directive, (8) a commissive, (9) an expressive, and (10) a declarative. Thus the conclusion of an argument can be an illocutionary act type of any kind: a representative, a directive, a commissive, an expressive, or a declarative.

A reason can be advanced as a reason against some claim as well as a reason for it. Consider the following example:

(11) Proponent: We need a concerted global reduction of greenhouse gas emissions to mitigate future climate disruption. Opponent: A cost-benefit analysis needs to be done first to dete r mine whether it makes more sense to adapt to future climate disruption rather than to mitigate it.

Here the opponent’s reason is put forward as a reason against the proponent’s claim. The exchange has an inferential structure that is quite parallel to that in which a reason is put forward in support of a claim. In general, objections and criticisms seem to have just the same inferential structure as supports. In other words, there can be arguments against something as well as arguments for something. Consider an example. In the 11th century the monk Gaunilon objected to Anselm’s ontological argument for the existence of God that by the same reasoning one could prove the existence of a perfect island (Anselm 1903/1077-78). Gaunilon’s objection is an argument against the cogency of Anselm’s argument. It would involve needless and misleading subtlety to recast his objection as an argument in support of some claim. It is better to follow a number of authors who have recognized that there can be arguments against as well as arguments for (Johnson 2000; Rahwan et al. 2009; Freeman 2010; Wohlrapp 2014/2008).

In fact, the same reason can be adduced for a claim by one person and against the same claim by another person. For example, some people use the principle of self-determination as a reason for legalizing voluntary euthanasia, whereas others use it as a reason against legalizing voluntary euthanasia (Wohlrapp 2014/2008, pp. 264-265 [5] ). Each group advances an argument, and the two arguments clearly differ from each other. Thus it makes sense to add to the conception of an argument as a premiss-conclusion or claim-reason complex a third component indicating whether the reasons are to count for or against the claim. Further, to accommodate the existence of arguments against as well as arguments for, I shall hereafter use the term ‘target’ rather than ‘conclusion’ or ‘claim’ for the part of an argument to which its reasons are directed.

We are now in a position to say what a simple argument is:

A simple argument consists of one or more of the types of expression that can function as reasons, a “target” (any type of expression), and an indicator of whether the reasons count for or against the target. [6]

There may be no tokens of the component illocutionary act types. In other words, simple arguments as just defined are abstract structures that are not necessarily actually realized. We need impose no further restrictions on what can count as a simple argument, thus widening the class of arguments to the craziest combinations that one can imagine.

What gives such a set unity as a single argument is that someone puts forward or entertains, that is—adduces—its reasons as support for its target. In doing so, the person considers that the reasons, if true or otherwise acceptable, provide grounds for accepting or rejecting the target (to an extent indicated). Normally, the assumption motivating adducing the argument is that the person addressed by, or who considers, the argument did not previously think that the reasons provide the claimed support for, or opposition to, the target.

Goddu (2018) has objected to this way of securing the unity of an actualized argument. He contends that a person can entertain an argument mentally without supposing that its reasons support (or oppose) its target. One can for example wonder whether the reasons in an argument one is considering actually support the target. This is true, but in such a case the person considering the argument is viewing it as an argument that someone might or could adduce, i.e., as a hypothetical argument, a possible complex of reasons, indicator, and target.

Someone who adduces reasons as counting for or against a target must express the indicator, and must be the author of either the reasons or the target. But such an adducer need not be the author of both reasons and target. One can draw a conclusion from something someone else has said, in which case the person who draws the conclusion adduces what the other person said as supporting the conclusion drawn. One can provide reasons against someone else’s claim, in which case the person who provides the reasons adduces them as opposing the other person’s claim. In any situation where an argument is expressed, the adducer is the person who articulates the inferential claim conveyed by the indicator that points to the argument’s target.

3. Complex arguments

So far this conception of an argument accommodates only simple arguments, i.e. single-inference arguments with a set of one or more reasons, a target, and an indication of whether the reasons count for or against the target. We need to allow as well for complex arguments that involve a chain of reasoning or embedded suppositional reasoning.

3.1 Chain of reasoning arguments

In chained arguments, a reason of one argument (which I will call ‘the superordinate argument’) is the target of another (which I will call ‘the subordinate argument’ or ‘sub-argument’). Since only representatives can be reasons, the target of any subordinate argument must be a representative. There is no limit to the depth of chaining. The ultimate target in a chain of reasoning is supported or opposed by one or more reasons, each of which may be the target of one or more reasons in a sub-argument, each of which in turn may be the target of one or more reasons in a sub-sub-argument, and so on indefinitely. In an expressed sub-argument at any level, the reasons must be adduced in support of the target. Otherwise the target would have to be the complement of the reason in the superordinate argument to which it was linked. But it is hard to define the complement of a representative illocutionary act. What, for example, is the complement of a hedged assertion of the form ‘probably p ’? Representatives incompatible with ‘probably p ’ include ‘definitely p ’, ‘probably p ′ ’, and ‘definitely p ′ ’, where p ′ is a contradictory of p . An argument against some target that was used to support a reason of the form ‘probably p ’ would therefore need an unwieldy disjunction as its target, for which it would be difficult if not impossible to formulate a set of reasons that successfully opposed each disjunct simultaneously. Since subordinate simple arguments in an expressed complex argument make sense only if their reasons are presented in support of their target, it makes sense to limit unexpressed subordinate simple arguments in the same way.

The natural way to accommodate the indefinite complexity of chained arguments is to use a recursion clause that can be applied again and again so as to build up arguments of increasing complexity. The process is analogous to that by which one defines what a person’s ancestor is by saying that a parent of a person is an ancestor of that person and that a parent of any ancestor of that person is also an ancestor of that person. This definition allows one to construct the class of a person’s ancestors, starting with the person’s parents, then adding the grandparents, then the great-grandparents, and so on without end.

In defining recursively what an argument is, one needs to take some care in constructing the recursion clause for chaining arguments. The most sensible way to do so seems to be to add one at a time a simple argument for a reason in an already constructed argument. One can conceive of a simple argument, which is a triple, as a unit set, a set with one member. One can combine it with a simple argument whose target is a reason in the first argument by taking the union of the two sets, i.e., the set whose members are all the triples that are members of either set. And then one can combine this set of two triples with a third simple argument whose target is a reason in one of the first two triples. And so on. Let us call a reason in any triple in a set of such triples a ‘reason in the argument’. The recursion clause might then read as follows:

If in an argument something is a reason but is not a target, then the union of that argument with a simple argument whose target is that reason and whose indicator is positive is also an argument.

As with the definition of simple arguments, this clause allows that the most fantastic and crazy combinations are arguments in the abstract sense. The condition that the reason is not already a target is meant to exclude from being a single argument structures in which a reason is the target of more than one simple argument. Just as multiple arguments for or against the same ultimate target do not constitute a single argument, so too multiple arguments for the same intermediate target cannot be components of a single complex argument.

3.2 Embedded suppositional reasoning

Chaining is one of two ways to construct complex arguments. The other is embedding, where suppositional reasoning is used to support or oppose a target, with one or more of its suppositions being “discharged” in the process. (E.g., “Suppose the U.S. did not use the atomic bombs in WWII. Had that been the case, then probably…” or “Suppose we take on the debt of a big mortgage and buy a house. If we were to do that, then …”.) Any line of suppositional reasoning is an argument according to the recursive definition of argument developed so far. To allow for embedding one or more such lines of suppositional reasoning, we need to allow that a line of suppositional reasoning can count as something like a reason. [7] One way to do so is to take the line of suppositional reasoning as an implicit assertion that the ultimate target of the line of suppositional reasoning follows from its ultimate supposition in combination with any other ultimate reasons used in derivation of the ultimate target. (The assertion may be qualified, if either an inference or an ultimate reason in the suppositional reasoning is qualified.)

When the suppositional reasoning is embedded in a larger context, the target external to this line of reasoning is a representative, which in the case of nested suppositional reasoning may itself have a suppositional status. The recursion clause allowing embedding of suppositional reasoning thus needs to allow for the dual complexity of chains of reasoning from suppositions and nesting of suppositional reasoning inside suppositional reasoning. It also needs to allow that a line of suppositional reasoning can be used in opposition to a target as well in support of one. If the target of a line of suppositional reasoning is a reason in a sub-argument, however, then the expression of such a complex argument makes sense only if the suppositional reasoning is adduced in support of the target, for the same reason that an expressed chained simple sub-argument makes sense only if its reasons are adduced in support of its target: an opposed target would have to be too complex to count as the complement of the reason in the superordinate argument that is being indirectly supported by opposition to the target of the suppositional reasoning.

In general, too, it makes sense to use a line of suppositional reasoning only if its internal ultimate target is argued for rather than against, since all the recognized legitimate ways of discharging a supposition assume that the supposition is used to support the ultimate target. Similar restrictions to arguments with a positive indicator are therefore appropriate for abstract arguments that need not be expressed. It seems an unnecessary further complication, however, to incorporate in a clause allowing embedding the specific ways in which a supposition in a piece of suppositional reasoning may legitimately be discharged. [8] The abstract definition of an argument will thus allow for embedding pieces of suppositional reasoning in totally illegitimate ways.

The following is a possible recursion clause allowing embedding;

A triple is an argument if its first member is a set whose members include at least one argument with a suppositional ultimate reason, whose third member (the target) is an illocutionary act of any kind, and whose second member is an indicator of whether the members of the set count for or against the target.

As is usual with recursive definitions, there needs to be a final closure clause to the effect that nothing is an argument unless it is an argument according to the base clause and the recursion clauses. [9] One can illustrate and test the resulting definition by using its clauses to construct complex arguments as they appear in argumentative texts.

As with the abstract concept of a single argument, we need a basis for the unity of an expressed complex argument. An expressed chaining of two arguments is a complex illocutionary act of adducing the resulting chain of reasoning as supporting or opposing the ultimate target of the superordinate argument in the chain (i.e. the argument that has a reason which the subordinate simple argument targets). The essence of adducing in this case is that the utterance of the adducer counts as a claim that in each link of the chain the reasons if true or otherwise acceptable would provide epistemic support for the target or as a claim that the reasons if true or otherwise acceptable would provide epistemic opposition to the target. An embedding of an argument is a complex act of adducing the embedded suppositional reasoning, possibly along with one or more reasons, as support for or opposition to the target of the argument in which the suppositional reasoning is embedded. The essence of adducing in this case is that the utterance of the adducer counts as a claim that the suppositional reasoning would if the additional reasons (if any) were true or otherwise acceptable provide epistemic support for the target or as a claim that the suppositional reasoning would if the additional reasons (if any) were true or otherwise acceptable provide epistemic opposition to the target. The content conditions, preparatory conditions and sincerity conditions for these more complex acts of adducing are a function of the content, preparatory and sincerity conditions for the simple acts of adducing from which they are constituted.

As with simple expressed arguments, we can accommodate complex arguments that are merely considered by a hypothetically possible act of adducing. If one is considering a complex abstract argument as a whole that could be used to adduce the reasons as supporting or opposing its ultimate target, then one is considering an argument.

The conception of an argument that I propose has the following distinctive features:

• It takes the ultimate constituents of arguments to be illocutionary act types rather than propositions, statements, utterances, and the like.
• It allows for arguments against something as well as arguments for something.
• It allows the reasons in an argument to be any kind of representative illocutionary act.
• It allows arguments to have as their target any kind of illocutionary act.
• It distinguishes arguments as abstract structures that may never be expressed or even thought of from expressed arguments.
• It locates the unity of an expressed or mentally entertained argument in a second-order illocutionary act of adducing, which may be actual or merely hypothetically entertained.
• It allows for a variety of uses of arguments, since neither the abstract conception of an argument nor the act of adducing that constitutes a complex of illocutionary act types as a single argument includes any conception of the purpose or function of an argument.
• It provides explicitly for complex arguments to be constructed recursively by steps of chaining and embedding.

Anselm, Saint (1903/1077-78). Proslogium ; Monologium : An appendix in behalf of the fool by Gaunilo ; and Cur deus homo , translated from the Latin by Sidney Norton Deane, B.A. with an introduction, bibliography, and reprints of the opinions of leading philosophers and writers on the ontological argument. Chicago: Open Court. Latin original of the Proslogium written in 1077-78.

Diogenes Laertius (1925/ca. 210-240). Lives of eminent philosophers , with an English translation by R. D. Hicks, 2 vols. Loeb Classical Library 184 and 185. Cambridge, Mass.: Harvard University Press. First published ca. 210-240 CE.

Ennis, Robert H. (2006). ‘Probably’. In David Hitchcock & Bart Verheij (Eds.), Arguing on the Toulmin model: New essays on argument analysis and evaluation (pp. 145-164). Dordrecht: Springer.

Freeman, James B. (2010). Commentary on Geoffrey C. Goddu’s “Refining Hitchcock’s definition of ‘argument’”. In Juho Ritola (Ed.), Argument cu l tures: Proceedings of OSSA 09 , CD-ROM (pp. 1-10). Windsor, ON: OSSA. Available at http://scholar.uwindsor.ca/cgi/viewcontent.cgi?article=1141&context=ossaarchive .

Goddu, Geoffrey C. (2018). Against the intentional definition of argument. In Steve Oswald and Didier Maillat (Eds .), Proceedings of the Second E u ropean Conference on Argumentation, University of Fribourg, Switzerland, 20-23 June 2017 , Vol. II (pp. 337-346). London: College Publications.

Hitchcock, David (2006). Informal logic and the concept of argument. In Dale Jacquette (Ed.), Philosophy of logic , volume 5 of Dov M. Gabbay, Paul Thagard & John Woods (Eds.), Handbook of the philosophy of sc i ence (pp. 101-129). Amsterdam: North Holland.

Hitchcock, David (2017). The concept of argument. In David Hitchcock, On reasoning and argument: Essays in informal logic and on critical thinking (pp. 518-529). Dordrecht: Springer.

Johnson, Ralph H. (2000). Manifest rationality: A pragmatic theory of a r gument . Mahwah, NJ: Lawrence Erlbaum Associates.

Kahneman, Daniel (2011). Thinking, fast and slow . New York: Farrar, Straus and Giroux.

Rahwan, Iyad, & Chris Reed (2009). The Argument Interchange Format. In Guillermo R. Simari (Ed.), Argumentation in artificial intelligence (pp. 383-402). Boston: Springer.

Searle, John R. (1976). A classification of illocutionary acts. Language in Society , 5(1): 1-23.

Toulmin, Stephen Edelston (1958). The uses of argument . Cambridge: Cambridge University Press.

Wohlrapp, Harald R. (2014/2008). The concept of argument: A philosoph i cal foundation . Dordrecht: Springer. German original first published in 2008.

• © David Hitchcock ↵
• This chapter uses material from “The concept of argument” (Hitchcock 2017, pp. 518-529; © Springer International Publishing AG 2017), with permission of Springer. ↵
• ‘Premise’ and ‘premiss’ are both acceptable spellings of the word. Some authors prefer the first, which is more common in the USA; some prefer the second, which is found more often in Great Britain. ↵
• As Toulmin (1958, pp. 47-62) and Ennis (2006, pp. 145-164) have argued. ↵
• Wohlrapp argues that if voluntary euthanasia becomes legal on the basis that self-determination requires it, those whose condition might qualify them for approval to be euthanized but who want merely to live out the remainder of their natural lives are pressured by appeals to self-determination to submit to euthanasia. The supposedly liberating value becomes coercive. ↵
• More precisely: A simple argument is a triple whose first member is a set of one or more representative illocutionary act types (called ‘the reasons’), whose third member (called ‘the target’) is an illocutionary act type of any kind, and whose second member is an indicator of whether the reasons count for or against the target. ↵
• It won’t do, however, to count it as a reason in the same sense as that in which a representative is a reason. Otherwise the recursion clause for chaining would allow for arguments that are subordinate to a line of suppositional reasoning, which makes no sense. ↵
• One way of legitimately discharging a supposition is conditional proof, in which one derives a conditional from a line of suppositional reasoning that starts from the supposition of the conditional’s antecedent and ends with the conditional’s consequent. A variant form of conditional proof starts from the supposition of a contradictory of a conditional’s consequent and ends with a contradictory of its antecedent. Another way to legitimately discharge a supposition is reductio ad absurdum, in which one uses a line of reasoning from a supposition to some absurdity as a reason for denying the supposed proposition. Another is argument by cases, in which one considers an allegedly exhaustive set of possible cases, deriving the same ultimate target from the supposition of each case, and then drawing this ultimate target as a conclusion. Another is to argue for a proposition in a proof by mathematical induction by supposing at the inductive step that the proposition holds for the number n (or for every number up to and including n) and deriving from this supposition that then it also holds for the number n 1. Another is universal generalization, in which one derives a universal generalization about a kind by reasoning from the supposition that some individual is of that kind to the conclusion that the generalization holds for this individual, without using any other assumption about the individual. ↵
• One can express the recursive definition in the customary form of a statement in which there appears in the first part the term to be defined, in the last part the defining part of the definition, and in between these two parts an indicator (such as ‘means’, ‘=df’, ‘if and only if’, or ‘is a’) that the defining part states the meaning of the defined term. For example, one could say that something is an argument if and only if it belongs to every set that includes everything that satisfies the base clause, as well as everything that can be constructed from its members using the recursion clauses for chaining and embedding. ↵

Studies in Critical Thinking Copyright © by David Hitchcock is licensed under a Creative Commons Attribution 4.0 International License , except where otherwise noted.

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Arguing Using Critical Thinking

(2 reviews)

Jim Marteney, Los Angeles Valley College

Copyright Year: 2020

Publisher: Academic Senate for California Community Colleges

Language: English

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Reviewed by Steve Gimbel, Professor, Gettysburg College on 9/29/22

There are separate sections on how to formulate an argument, how to evaluate an argument, the burdens adopted by those engaging in critical discourse, rhetorical strategies for effectively convincing an interlocutor, and errors in reasoning. In... read more

Comprehensiveness rating: 4 see less

There are separate sections on how to formulate an argument, how to evaluate an argument, the burdens adopted by those engaging in critical discourse, rhetorical strategies for effectively convincing an interlocutor, and errors in reasoning. In terms of the breadth of topics one generally wants covered in a critical thinking class, the book does a fine job at hitting them all.

Content Accuracy rating: 2

It is an admirable attempt to develop a post-modern, post-truth approach to critical discourse. "Truth is a word best avoided entirely in argumentation," the book tells students, "except when placed in quotes or with careful qualification." Invoking Wittgenstein and Sapir-Whorf in the introductory sections, the book seeks to develop a relational, psychological, rhetorical approach instead of one focused on informal logic. In doing so, it entirely removes the point of argumentation -- rational belief. Some things are true -- smoking DOES cause cancer, human activity is causing global warming, the Founders of the U.S. did want a separation between Church and State. These are true. There is a series of TED talks cited for inspirational rhetorical value, but in a world in which conspiracy theories are endangering democracy, we need to understand that replacing truth with the truthiness that emerges from this sort of post-modernism is playing directly into those who are undermining our discourse. It exacerbates the problem, it does not solve it.

Relevance/Longevity rating: 3

Since the book hinges less on logic and more on social science, there are elements that will be altered over time. Sapir-Whorf, as mentioned above, has not taken seriously by linguists for decades, yet is used as a foundation. The book seeks to speak to students using, in places, contemporary references that will become dated over time, but these are easily updated.

Clarity rating: 1

There are some very good sections in the book. The distinction it draws between matters of fact, value, and policy is very well done. As is the catalogue it gives of different sorts of evidence. The clarity with which it sets out the difference in burdens between the pro and anti sides of a debate is wonderful.

In terms of accessibility, the book is written engagingly in a way that first year students should not be lost. It intentionally uses a new set of technical terms modeled on standard usage -- claim, evidence, issues, contentions, cases,... and does well to define them in accessible (at times loosey-goosey) ways.

However, there are problems for those trying to teach critical thinking as informal logic. You will not find the words "conclusion" or "premise" anywhere in the book. This is clearly intentional as it seeks to eliminate the idea of arguments as providing good reason to believe something is true. Again, truth is not to be discussed. Instead, it sort of tries to use a sort of sliding scale, but it is never at all clear what the scale is actually measuring. The book uses the term validity (much more on that below), but that term is used in a stunningly ambiguous way.

Consistency rating: 2

The central notion in the book is validity. This is not unexpected as that is a standard term in logic. As logicians use the word, an argument is valid if and only, assuming the truth of the premises for the sake of argument, the conclusion is at least likely true, that is, the truth of the conclusion is imp;lied by the truth of the premises. Validity is a matter relating to the internal structure of an argument, connecting the posited truth of the premises to the consequential necessary or probable truth of the conclusion. Yet the book says something quite different, "Critical thinkers need to remember that there is no necessary or inherent connection between Truth and validity." Ummmmm? Validity is DEFINED in terms of a relation between premises and conclusion and how that relation determines or does not determine truth. There could not be a MORE inherent connection between truth and validity.

It is clear that by "capital T Truth," the book is looking to encourage students not to be absolutists, to be able to question deeply held convictions and this is, indeed, a necessary function of any critical thinking class, but with its post-truth orientation, the book uses the term "validity" as a replacement for it in several completely different and inconsistent ways. At times, it is uses validity as a replacement for the truth concept. In this way, sentences are more or less valid, that is, truer or less true. This is the "sliding bead" model that is repeatedly alluded to throughout the text.

At other times, however, the usual meaning of validity is used, where it is not sentences, but arguments that can be valid or invalid according to whether or not the conclusion (claim) is properly connected to the premises (evidence). There is a loose, hand-waving section on what this sense of validity means. In most texts, this is the HEART of critical thinking. How to tell valid from invalid arguments.

At yet other times, there is a third use of the term validity. A viewpoint is more or less valid based upon the support it receives from arguments in favor of it. Unlike the traditional sense of validity, this is not a particular argument that is evaluated as successful in terms of its inner-structure, and it is not the likely truth or falsity of the conclusion of a particular argument, but a more general sense of the degree to which a perspective has arguments to bolster it.

This sort of slipperiness in the central notion of the entire course is problematic. The point of good reasoning is clarity and rigor. But that is exactly what this book tries to eliminate.

Modularity rating: 3

There are parts of this text that are fantastic and which I could absolutely see wanting to use in my critical thinking class. However, because of the intentional avoidance of standard logical terminology and the unusual reinterpretations of the standard terms it does use, it would be difficult to use sections of this book in conjunctions with sections of other critical thinking texts.

Organization/Structure/Flow rating: 5

If one were to use this text as the centerpiece of a course on critical thinking, there is a clear and logical flow to the way the pieces build on themselves. There is motivation up front, tools in the middle, applications and concerns about misusing the tools in the end. The structural is well-thought out and well-executed. The one complaint in terms of organization is that it is two-thirds the way through the text before certain central notions are defined.

Interface rating: 5

It is a clean and effective design with images that brighten up the text without distracting. Easy to read and aesthetically well-laid out. There are a couple of line breaks that add a couple of blank lines where they don't need to be here and there, but that is nitpicky stuff. Overall, it looks great.

Grammatical Errors rating: 5

It is a clean and effective design with images that brighten up the text without distracting. Easy to read and aesthetically well-laid out. There are a couple of line breaks that add a couple of blank lines where they don't need to be here and there, but that is nitpicky stuff. Overall, it reads and looks great.

Cultural Relevance rating: 2

The text is not culturally insensitive, indeed, the problem with it is exactly the opposite. It is clear that part of the goal of this text is to change how we think about critical thinking, moving from a logical model in which we strive for truth, to a rhetorical model in which we engage in open dialogue across varied perspectives. This is a noble goal. However, in trying to create discourse communities where voices that are often underrepresented or silenced have a place, the book does away with the point of that discourse. We want multiple perspectives because they provide insights that lead to truths we may have otherwise missed. They are correctives that undermine problematic presuppositions we did not even realize we were making that leads us away from truth. They allow us to see other ways of valuing things that we would not have values under our initial set of meanings. Eliminating the centrality of truth as a goal in discourse does not create room for other voices, it eliminates the point of needing those other voices. Indeed, the unintentional consequence of this approach to critical thinking is the devaluing of rationality, of truth, of scientific findings. We need to take action to reverse climate change. This can only be done if we have a robust notion of truth and its importance.

Logic is an activity you learn by doing. The lack of exercises or active engagement projects in the text is something that would place a load on the instructor to develop if this were to be an effective book in use.

Reviewed by Marion Hernandez, Adjunct Instructor English Department/DCE, Bunker Hill Community College on 12/27/20, updated 1/6/21

The book does name, identify and define key terms of argument and the basis for effective argument. read more

The book does name, identify and define key terms of argument and the basis for effective argument.

Content Accuracy rating: 4

This text has no grammatical errors and is unbiased in the definitions and the various contexts in which arguments occur.

Relevance and longevity do not really apply to the subject and context of this text. The book is very general and the time and place do not play a role.

Clarity rating: 2

The definitions and graphs/charts (only 2 or 3 have been added) are very basic, almost to the point of being counter productive. The Inductive and deductive chart has no value in the design or in the side notes accompanying the graph. No enough detail or design features were added to this one graph.

Consistency is not a feature to discuss because every chapter has a different main idea from types of arguments to resolving arguments to types of behavior commonly seen during arguments. There is no sequencing of material from beginning to end in term of moving from basic through intermediate and advanced level of thinking.

The book clearly defines the title of each section, but again, all taken together, no advancement in theory is developed throughout.

Organization/Structure/Flow rating: 2

The chapters do not appear in any type of order. The book moves from arguing to argument and behaviors commonly found during arguments. The last chapters talk about reasoning skills such as inductive and deductive thinking.

Interface rating: 1

The graphic and pictures do nothing to promote thinking or understanding and are therefore superfluous.

Grammatical Errors rating: 2

This critique here is not so much grammar but but point of view. The book really reads like a self help book or guide for a very basic reader. But the point of view shifts from 'you" as is what "you" should do to the the third person "they". This is very poor writing and leads to the next point which is its lack of value as a high school or college text. It is difficult to understand what student and in what circumstances would benefit or be inspired to read it.

Cultural Relevance rating: 5

There is no politically incorrect content.

As briefly mentioned, the causal, offhand, self help nature of this book is not designed in any way to be used as a text. Because each chapter is separate with no sequencing, it would be impossible to develop any in depth assignments, No exercises are added so nothing would materialize in the way of theory, practice, analysis or discussion.

Table of Contents

• 1: Standing Up For Your Point Of View
• 2: Communicating An Argument
• 5: Building Your Case With Issues, Analysis And Contentions
• 6: Evidence
• 7: Reasoning
• 8: Validity Or Truth
• 9: Changing Beliefs, Attitudes and Behavior
• 10: Decision Making - Judging an Argument
• 11: Discovering, Examining and Improving Our Reality
• 12: The Foundations of Critical Thinking

Ancillary Material

About the book.

There is a quote that has been passed down many years and is most recently accounted to P.T. Barnum, “There is a sucker born every minute.” Are you that sucker? If you were, would you like to be “reborn?” The goal of this book is to help you through that “birthing” process. Critical thinking and standing up for your ideas and making decisions are important in both your personal and professional life. How good are we at making the decision to marry? According to the Centers for Disease Control, there is one divorce in America every 36 seconds. That is nearly 2,400 every day. And professionally, the Wall Street Journal predicts the average person will have 7 careers in their lifetime. Critical thinking skills are crucial.

Critical thinking is a series learned skills. In each chapter of this book you will find a variety of skills that will help you improve your thinking and argumentative ability. As you improve, you will grow into a more confident person being more in charge of your world and the decisions you make.

About the Contributors

Jim Marteney , Professor Emeritus (Communication Studies) at Los Angeles Valley College

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Critical thinking

Categories of arguments.

A key skill when evaluating information is the ability to evaluate the strength of an argument and decide whether it’s reasonable. But what do we mean when we talk about arguments? Pause for a moment to consider the following question. When you have an answer, turn the card to learn more.

Arguments can be divided into two categories:

Deductive arguments

If premises are true, then conclusions must also be true.

Example : Claire likes cats. Bella is a cat. Therefore, Claire likes Bella.

Inductive arguments

If premises are true or have a high likelihood of being true, then conclusions are likely to be true, but not guaranteed.

Example : In most cases, where there is smoke, there is fire. There is smoke on the mountain. Therefore there is probably a fire on the mountain.

Let’s explore through an example the different ways deductive and inductive arguments are constructed and analysed.

Evaluating arguments

Arguments can be evaluated by following four steps:

• Begin by deconstructing the argument so that you can identify its premises, the assumptions that underpin in, and its conclusions.
• Establish whether the argument is deductive or inductive
• Determine whether the argument is logically valid. Does the conclusion follow from the premises? Is there any missing information or hidden premises that would be required to make the conclusion valid?
• If you feel that the conclusions are valid, check that the premises are true

Evaluating arguments can be difficult at first. For an example of evaluation in action, watch this video which evaluates a common argument connected to climate change produced by staff at the University of Queensland (and if you’re interested you can read their full paper examining this issue).

Unit 1: What Is Philosophy?

LOGOS: Critical Thinking, Arguments, and Fallacies

Heather Wilburn, Ph.D

Critical Thinking:

With respect to critical thinking, it seems that everyone uses this phrase. Yet, there is a fear that this is becoming a buzz-word (i.e. a word or phrase you use because it’s popular or enticing in some way). Ultimately, this means that we may be using the phrase without a clear sense of what we even mean by it. So, here we are going to think about what this phrase might mean and look at some examples. As a former colleague of mine, Henry Imler, explains:

By critical thinking, we refer to thinking that is recursive in nature. Any time we encounter new information or new ideas, we double back and rethink our prior conclusions on the subject to see if any other conclusions are better suited. Critical thinking can be contrasted with Authoritarian thinking. This type of thinking seeks to preserve the original conclusion. Here, thinking and conclusions are policed, as to question the system is to threaten the system. And threats to the system demand a defensive response. Critical thinking is short-circuited in authoritarian systems so that the conclusions are conserved instead of being open for revision. [1]

A condition for being recursive is to be open and not arrogant. If we come to a point where we think we have a handle on what is True, we are no longer open to consider, discuss, or accept information that might challenge our Truth. One becomes closed off and rejects everything that is different or strange–out of sync with one’s own Truth. To be open and recursive entails a sense of thinking about your beliefs in a critical and reflective way, so that you have a chance to either strengthen your belief system or revise it if needed. I have been teaching philosophy and humanities classes for nearly 20 years; critical thinking is the single most important skill you can develop. In close but second place is communication, In my view, communication skills follow as a natural result of critical thinking because you are attempting to think through and articulate stronger and rationally justified views. At the risk of sounding cliche, education isn’t about instilling content; it is about learning how to think.

In your philosophy classes your own ideas and beliefs will very likely be challenged. This does not mean that you will be asked to abandon your beliefs, but it does mean that you might be asked to defend them. Additionally, your mind will probably be twisted and turned about, which can be an uncomfortable experience. Yet, if at all possible, you should cherish these experiences and allow them to help you grow as a thinker. To be challenged and perplexed is difficult; however, it is worthwhile because it compels deeper thinking and more significant levels of understanding. In turn, thinking itself can transform us not only in thought, but in our beliefs, and our actions. Hannah Arendt, a social and political philosopher that came to the United States in exile during WWII, relates the transformative elements of philosophical thinking to Socrates. She writes:

Socrates…who is commonly said to have believed in the teachability of virtue, seems to have held that talking and thinking about piety, justice, courage, and the rest were liable to make men more pious, more just, more courageous, even though they were not given definitions or “values” to direct their further conduct. [2]

Thinking and communication are transformative insofar as these activities have the potential to alter our perspectives and, thus, change our behavior. In fact, Arendt connects the ability to think critically and reflectively to morality. As she notes above, morality does not have to give a predetermined set of rules to affect our behavior. Instead, morality can also be related to the open and sometimes perplexing conversations we have with others (and ourselves) about moral issues and moral character traits. Theodor W. Adorno, another philosopher that came to the United States in exile during WWII, argues that autonomous thinking (i.e. thinking for oneself) is crucial if we want to prevent the occurrence of another event like Auschwitz, a concentration camp where over 1 million individuals died during the Holocaust. [3] To think autonomously entails reflective and critical thinking—a type of thinking rooted in philosophical activity and a type of thinking that questions and challenges social norms and the status quo. In this sense thinking is critical of what is, allowing us to think beyond what is and to think about what ought to be, or what ought not be. This is one of the transformative elements of philosophical activity and one that is useful in promoting justice and ethical living.

With respect to the meaning of education, the German philosopher Hegel uses the term bildung, which means education or upbringing, to indicate the differences between the traditional type of education that focuses on facts and memorization, and education as transformative. Allen Wood explains how Hegel uses the term bildung: it is “a process of self-transformation and an acquisition of the power to grasp and articulate the reasons for what one believes or knows.” [4] If we think back through all of our years of schooling, particularly those subject matters that involve the teacher passing on information that is to be memorized and repeated, most of us would be hard pressed to recall anything substantial. However, if the focus of education is on how to think and the development of skills include analyzing, synthesizing, and communicating ideas and problems, most of us will use those skills whether we are in the field of philosophy, politics, business, nursing, computer programming, or education. In this sense, philosophy can help you develop a strong foundational skill set that will be marketable for your individual paths. While philosophy is not the only subject that will foster these skills, its method is one that heavily focuses on the types of activities that will help you develop such skills.

Let’s turn to discuss arguments. Arguments consist of a set of statements, which are claims that something is or is not the case, or is either true or false. The conclusion of your argument is a statement that is being argued for, or the point of view being argued for. The other statements serve as evidence or support for your conclusion; we refer to these statements as premises. It’s important to keep in mind that a statement is either true or false, so questions, commands, or exclamations are not statements. If we are thinking critically we will not accept a statement as true or false without good reason(s), so our premises are important here. Keep in mind the idea that supporting statements are called premises and the statement that is being supported is called the conclusion. Here are a couple of examples:

Example 1: Capital punishment is morally justifiable since it restores some sense of

balance to victims or victims’ families.

Let’s break it down so it’s easier to see in what we might call a typical argument form:

Premise: Capital punishment restores some sense of balance to victims or victims’ families.

Conclusion: Capital punishment is morally justifiable.

Example 2 : Because innocent people are sometimes found guilty and potentially

executed, capital punishment is not morally justifiable.

Premise: Innocent people are sometimes found guilty and potentially executed.

Conclusion: Capital punishment is not morally justifiable.

It is worth noting the use of the terms “since” and “because” in these arguments. Terms or phrases like these often serve as signifiers that we are looking at evidence, or a premise.

Check out another example:

Example 3 : All human beings are mortal. Heather is a human being. Therefore,

Heather is mortal.

Premise 1: All human beings are mortal.

Premise 2: Heather is a human being.

Conclusion: Heather is mortal.

In this example, there are a couple of things worth noting: First, there can be more than one premise. In fact, you could have a rather complex argument with several premises. If you’ve written an argumentative paper you may have encountered arguments that are rather complex. Second, just as the arguments prior had signifiers to show that we are looking at evidence, this argument has a signifier (i.e. therefore) to demonstrate the argument’s conclusion.

So many arguments!!! Are they all equally good?

No, arguments are not equally good; there are many ways to make a faulty argument. In fact, there are a lot of different types of arguments and, to some extent, the type of argument can help us figure out if the argument is a good one. For a full elaboration of arguments, take a logic class! Here’s a brief version:

Deductive Arguments: in a deductive argument the conclusion necessarily follows the premises. Take argument Example 3 above. It is absolutely necessary that Heather is a mortal, if she is a human being and if mortality is a specific condition for being human. We know that all humans die, so that’s tight evidence. This argument would be a very good argument; it is valid (i.e the conclusion necessarily follows the premises) and it is sound (i.e. all the premises are true).

Inductive Arguments : in an inductive argument the conclusion likely (at best) follows the premises. Let’s have an example:

Example 4 : 98.9% of all TCC students like pizza. You are a TCC student. Thus, you like pizza.

Premise 1: 98.9% of all TCC students like pizza

Premise 2: You are a TCC student.

Conclusion: You like pizza. (*Thus is a conclusion indicator)

In this example, the conclusion doesn’t necessarily follow; it likely follows. But you might be part of that 1.1% for whatever reason. Inductive arguments are good arguments if they are strong. So, instead of saying an inductive argument is valid, we say it is strong. You can also use the term sound to describe the truth of the premises, if they are true. Let’s suppose they are true and you absolutely love Hideaway pizza. Let’s also assume you are a TCC student. So, the argument is really strong and it is sound.

There are many types of inductive argument, including: causal arguments, arguments based on probabilities or statistics, arguments that are supported by analogies, and arguments that are based on some type of authority figure. So, when you encounter an argument based on one of these types, think about how strong the argument is. If you want to see examples of the different types, a web search (or a logic class!) will get you where you need to go.

Some arguments are faulty, not necessarily because of the truth or falsity of the premises, but because they rely on psychological and emotional ploys. These are bad arguments because people shouldn’t accept your conclusion if you are using scare tactics or distracting and manipulating reasoning. Arguments that have this issue are called fallacies. There are a lot of fallacies, so, again, if you want to know more a web search will be useful. We are going to look at several that seem to be the most relevant for our day-to-day experiences.

• Inappropriate Appeal to Authority : We are definitely going to use authority figures in our lives (e.g. doctors, lawyers, mechanics, financial advisors, etc.), but we need to make sure that the authority figure is a reliable one.

Things to look for here might include: reputation in the field, not holding widely controversial views, experience, education, and the like. So, if we take an authority figure’s word and they’re not legit, we’ve committed the fallacy of appeal to authority.

Example 5 : I think I am going to take my investments to Voya. After all, Steven Adams advocates for Voya in an advertisement I recently saw.

If we look at the criteria for evaluating arguments that appeal to authority figures, it is pretty easy to see that Adams is not an expert in the finance field. Thus, this is an inappropropriate appeal to authority.

• Slippery Slope Arguments : Slippery slope arguments are found everywhere it seems. The essential characteristic of a slippery slope argument is that it uses problematic premises to argue that doing ‘x’ will ultimately lead to other actions that are extreme, unlikely, and disastrous. You can think of this type of argument as a faulty chain of events or domino effect type of argument.

Example 6 : If you don’t study for your philosophy exam you will not do well on the exam. This will lead to you failing the class. The next thing you know you will have lost your scholarship, dropped out of school, and will be living on the streets without any chance of getting a job.

While you should certainly study for your philosophy exam, if you don’t it is unlikely that this will lead to your full economic demise.

One challenge to evaluating slippery slope arguments is that they are predictions, so we cannot be certain about what will or will not actually happen. But this chain of events type of argument should be assessed in terms of whether the outcome will likely follow if action ‘x” is pursued.

• Faulty Analogy : We often make arguments based on analogy and these can be good arguments. But we often use faulty reasoning with analogies and this is what we want to learn how to avoid.

When evaluating an argument that is based on an analogy here are a few things to keep in mind: you want to look at the relevant similarities and the relevant differences between the things that are being compared. As a general rule, if there are more differences than similarities the argument is likely weak.

Example 7 : Alcohol is legal. Therefore, we should legalize marijuana too.

So, the first step here is to identify the two things being compared, which are alcohol and marijuana. Next, note relevant similarities and differences. These might include effects on health, community safety, economic factors, criminal justice factors, and the like.

This is probably not the best argument in support for marijuana legalization. It would seem that one could just as easily conclude that since marijuana is illegal, alcohol should be too. In fact, one might find that alcohol is an often abused and highly problematic drug for many people, so it is too risky to legalize marijuana if it is similar to alcohol.

• Appeal to Emotion : Arguments should be based on reason and evidence, not emotional tactics. When we use an emotional tactic, we are essentially trying to manipulate someone into accepting our position by evoking pity or fear, when our positions should actually be backed by reasonable and justifiable evidence.

Example 8 : Officer please don’t give me a speeding ticket. My girlfriend broke up with me last night, my alarm didn’t go off this morning, and I’m late for class.

While this is a really horrible start to one’s day, being broken up with and an alarm malfunctioning is not a justifiable reason for speeding.

Example 9 : Professor, I’d like you to remember that my mother is a dean here at TCC. I’m sure that she will be very disappointed if I don’t receive an A in your class.

This is a scare tactic and is not a good way to make an argument. Scare tactics can come in the form of psychological or physical threats; both forms are to be avoided.

• Appeal to Ignorance : This fallacy occurs when our argument relies on lack of evidence when evidence is actually needed to support a position.

Example 10 : No one has proven that sasquatch doesn’t exist; therefore it does exist.

Example 11 : No one has proven God exists; therefore God doesn’t exist.

The key here is that lack of evidence against something cannot be an argument for something. Lack of evidence can only show that we are ignorant of the facts.

• Straw Man : A straw man argument is a specific type of argument that is intended to weaken an opponent’s position so that it is easier to refute. So, we create a weaker version of the original argument (i.e. a straw man argument), so when we present it everyone will agree with us and denounce the original position.

Example 12 : Women are crazy arguing for equal treatment. No one wants women hanging around men’s locker rooms or saunas.

This is a misrepresentation of arguments for equal treatment. Women (and others arguing for equal treatment) are not trying to obtain equal access to men’s locker rooms or saunas.

The best way to avoid this fallacy is to make sure that you are not oversimplifying or misrepresenting others’ positions. Even if we don’t agree with a position, we want to make the strongest case against it and this can only be accomplished if we can refute the actual argument, not a weakened version of it. So, let’s all bring the strongest arguments we have to the table!

• Red Herring : A red herring is a distraction or a change in subject matter. Sometimes this is subtle, but if you find yourself feeling lost in the argument, take a close look and make sure there is not an attempt to distract you.

Example 13 : Can you believe that so many people are concerned with global warming? The real threat to our country is terrorism.

It could be the case that both global warming and terrorism are concerns for us. But the red herring fallacy is committed when someone tries to distract you from the argument at hand by bringing up another issue or side-stepping a question. Politicians are masters at this, by the way.

• Appeal to the Person : This fallacy is also referred to as the ad hominem fallacy. We commit this fallacy when we dismiss someone’s argument or position by attacking them instead of refuting the premises or support for their argument.

Example 14 : I am not going to listen to what Professor ‘X’ has to say about the history of religion. He told one of his previous classes he wasn’t religious.

The problem here is that the student is dismissing course material based on the professor’s religious views and not evaluating the course content on its own ground.

To avoid this fallacy, make sure that you target the argument or their claims and not the person making the argument in your rebuttal.

• Hasty Generalization : We make and use generalizations on a regular basis and in all types of decisions. We rely on generalizations when trying to decide which schools to apply to, which phone is the best for us, which neighborhood we want to live in, what type of job we want, and so on. Generalizations can be strong and reliable, but they can also be fallacious. There are three main ways in which a generalization can commit a fallacy: your sample size is too small, your sample size is not representative of the group you are making a generalization about, or your data could be outdated.

Example 15 : I had horrible customer service at the last Starbucks I was at. It is clear that Starbucks employees do not care about their customers. I will never visit another Starbucks again.

The problem with this generalization is that the claim made about all Starbucks is based on one experience. While it is tempting to not spend your money where people are rude to their customers, this is only one employee and presumably doesn’t reflect all employees or the company as a whole. So, to make this a stronger generalization we would want to have a larger sample size (multiple horrible experiences) to support the claim. Let’s look at a second hasty generalization:

Example 16 : I had horrible customer service at the Starbucks on 81st street. It is clear that Starbucks employees do not care about their customers. I will never visit another Starbucks again.

The problem with this generalization mirrors the previous problem in that the claim is based on only one experience. But there’s an additional issue here as well, which is that the claim is based off of an experience at one location. To make a claim about the whole company, our sample group needs to be larger than one and it needs to come from a variety of locations.

• Begging the Question : An argument begs the question when the argument’s premises assume the conclusion, instead of providing support for the conclusion. One common form of begging the question is referred to as circular reasoning.

Example 17 : Of course, everyone wants to see the new Marvel movie is because it is the most popular movie right now!

The conclusion here is that everyone wants to see the new Marvel movie, but the premise simply assumes that is the case by claiming it is the most popular movie. Remember the premise should give reasons for the conclusion, not merely assume it to be true.

• Equivocation : In the English language there are many words that have different meanings (e.g. bank, good, right, steal, etc.). When we use the same word but shift the meaning without explaining this move to your audience, we equivocate the word and this is a fallacy. So, if you must use the same word more than once and with more than one meaning you need to explain that you’re shifting the meaning you intend. Although, most of the time it is just easier to use a different word.

Example 18 : Yes, philosophy helps people argue better, but should we really encourage people to argue? There is enough hostility in the world.

Here, argue is used in two different senses. The meaning of the first refers to the philosophical meaning of argument (i.e. premises and a conclusion), whereas the second sense is in line with the common use of argument (i.e. yelling between two or more people, etc.).

• Henry Imler, ed., Phronesis An Ethics Primer with Readings, (2018). 7-8. ↵
• Arendt, Hannah, “Thinking and Moral Considerations,” Social Research, 38:3 (1971: Autumn): 431. ↵
• Theodor W. Adorno, “Education After Auschwitz,” in Can One Live After Auschwitz, ed. by Rolf Tiedemann, trans. by Rodney Livingstone (Stanford: Stanford University Press, 2003): 23. ↵
• Allen W. Wood, “Hegel on Education,” in Philosophers on Education: New Historical Perspectives, ed. Amelie O. Rorty (London: Routledge 1998): 302. ↵

LOGOS: Critical Thinking, Arguments, and Fallacies Copyright © 2020 by Heather Wilburn, Ph.D is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

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Critical Thinking: Defining an Argument, Premises, and Conclusions

Defining an Argument Argument: vas is das? For most of us when we hear the word ‘argument’ we think of something we’d rather avoid.  As it is commonly understood, an argument involves some sort of unpleasant confrontation (well, maybe not always unpleasant–it can feel pretty good when you win!).  While this is one notion of ‘argument,’ it’s (generally)  not  what the term refers to in philosophy. In philosophy what we mean by  argument  is “ a set  of reasons offered in support of a claim.”  An argument, in this narrower sense, also generally implies some sort of  structure .  For now we’ll ignore the more particular structural aspects and focus on the two primary elements that make up an argument: premises and conclusions. Lets talk about conclusions first because their definition is pretty simple.   A conclusion  is the final assertion that is supported with evidence and reasons.  What’s important is the relationship between premises and conclusions.   The premises  are independent reasons and evidence that support the conclusion.  In an argument, the conclusion should follow from the premises. Lets consider a simple example: Reason (1):  Everyone thought Miley Cyrus’ performance was a travesty.  Reason (2):   Some people thought her performance was offensive. Conclusion:   Therefore, some people thought her performance was both a travesty and offensive. Notice that so long as we accept reason 1 and reason 2 as true, then we  must  also accept the conclusion.  This is what we mean by “the conclusion ‘follows’ from the premises.” Lets examine premises a little more closely.   A premise  is any  reason  or  evidence  that supports the conclusion of the argument.    In the context of arguments we can use ‘reasons’, ‘evidence’, and ‘premises’ interchangeably.   For example, if my conclusion is that dogs are better pets than cats, I might offer the following reasons: (P1) dogs are generally more affectionate than cats and (P2) dogs are more responsive to their owners’ commands than cats. From my two premises, I infer my conclusion that (C) dogs are better pets than cats.

Lets return to the definition of an argument.  Notice that in the definition, I’ve said that arguments are  a set  of reasons.  While this isn’t  always  true, generally, a good argument will generally have more than one premise.   Heuristics for Identifying Premises and Conclusions Now that we know what each concept is, lets look at how to identify each one as we might encounter them “in nature” (e.g., in an article, in a conversation, in a meme, in a homework exercise, etc…).  First I’ll explain each heuristic, then I’ll apply them to some examples. Identifying conclusions:    The easiest way to go about decomposing arguments is to first try to find the conclusion.  This is a good strategy because there is usually only one conclusion so, if we can identify it, it means the rest of the passage are premises. For this reason, most of the heuristics focus on finding the conclusion.   Heuristic 1:    Look for the most controversial statement in the argument.   The conclusion will generally be the most controversial statement in the argument.  If you think about it, this makes sense.  Typically arguments proceed by moving from assertions (i.e., premises) the audience agrees with then showing how these assertions imply something that the audience might not have previously agreed with. Heuristic 2:    The conclusion is usually a statement that takes a position on an issue .  By implication, the premises will be reasons that support the position on the issue (i.e., the conclusion).  A good way to apply this heuristic is to ask “what is the arguer trying to get me to believe?”.  The answer to this question is generally going to be the conclusion. Heuristic 3:    The conclusion is usually ( but not always ) the first or last statement of the argument.  Heuristic 4:    The “because” test.   Use this method you’re having trouble figuring which of 2 statements is the conclusion.  The “because” test helps you figure out which statement is supporting which.  Recall that the premise(s) always supports the conclusion.  This method is best explained by using an example.  Suppose you encounter an argument that goes something like this: It’s a good idea to eat lots of amazonian jungle fruit.  It tastes delicious.  Also,  lots of facebook posts say that it cures cancer Suppose you’re having trouble deciding what the conclusion it.  You’ve eliminated “it tastes delicious” as a candidate but you still have to choose between “it’s a good idea to eat lots of amazonian jungle fruit” and “lots of facebook posts say that it cures cancer”.  To use the because test, read one statement after the other but insert the word “because” between the two and see what makes more sense.  Lets try the two possibilities: A:   It’s a good idea to eat lots of amazonian jungle fruit  because  lots of facebook posts say that it cures cancer. B:   Lots of facebook posts say that amazonian jungle fruit cures cancer  because  it’s a good idea to eat lots of it.  Which makes more sense?  Which is providing support for which?   The answer is A.  Lots of facebook posts saying something is a  reason  (i.e. premise) to believe that it’s a good idea to eat amazonian jungle fruit–despite the fact that it’s not a very good reason… Identifying the Premises Heuristic 1:   Identifying the premises once you’ve identified the conclusion is cake.  Whatever isn’t contained in the conclusion is either a premise or “filler” (i.e., not relevant to the argument).  We will explore the distinguishing between filler and relevant premises a bit later, so don’t worry about that distinction for now. Example 1 Gun availability should be regulated. Put simply, if your fellow citizens have easy access to guns, they’re  more likely to kill you  than if they don’t have access. Interestingly, this turned out to be true not just for the twenty-six developed countries analyzed, but on a State-to-State level too. http://listverse.com/2013/04/21/10-arguments-for-gun-control/

Ok, lets try heuristic #1.  What’s the most controversial statement?  For most Americans, it is probably that “gun availability should be regulated.”  This is probably the conclusion.  Just for fun lets try out the other heuristics. Heuristic #2 says we should find a statement that takes a position on an issue.  Hmmm… the issue seems to be gun control, and the arguer takes a position.  Both heuristics converge on “gun availability should be regulated.” Heuristic #3 says the conclusion will usually be the first or last statement.  Guess what? Same result as the other heuristics. Heuristic #4.   A:  Gun availability should be regulated  because  people with easy access to guns are more likely to kill you.  Or B:  People with easy access to guns are more likely to kill you  because  gun availability should be regulated. A is the winner. The conclusion in this argument is well established.  It follows that what’s left over are premises (support for the conclusion): (P1)   If your fellow citizens have easy access to guns, they’re more likely to kill you than if they don’t have access.  (P2)  Studies show that P1 is true, not just for the twenty-six developed countries analyzed, but on a State-to-State level too.  (C)  G un availability should be regulated. Example 2 If you make gun ownership a crime, then only criminals will have guns. This means only “bad” guys would have guns, while good people would by definition be at a disadvantage. Gun control is a bad idea. Heuristic #1:  What’s the most controversial statement? Probably “gun control is a bad idea.” Heuristic #2: Which statement takes a position on an issue? “Gun control is a bad idea.” Heuristic #3:  “Gun control is a bad idea” is last and also passed heuristic 1 and 2.  Probably a good bet as the conclusion.  Heuristic #4:   A: If you make gun ownership a crime, then only criminals will have guns because gun control is a bad idea.

B: Gun control is a bad idea because if you make gun ownership a crime, then only criminals will have guns.

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What Are Critical Thinking Skills and Why Are They Important?

Learn what critical thinking skills are, why they’re important, and how to develop and apply them in your workplace and everyday life.

We often use critical thinking skills without even realizing it. When you make a decision, such as which cereal to eat for breakfast, you're using critical thinking to determine the best option for you that day.

Critical thinking is like a muscle that can be exercised and built over time. It is a skill that can help propel your career to new heights. You'll be able to solve workplace issues, use trial and error to troubleshoot ideas, and more.

We'll take you through what it is and some examples so you can begin your journey in mastering this skill.

What is critical thinking?

Critical thinking is the ability to interpret, evaluate, and analyze facts and information that are available, to form a judgment or decide if something is right or wrong.

More than just being curious about the world around you, critical thinkers make connections between logical ideas to see the bigger picture. Building your critical thinking skills means being able to advocate your ideas and opinions, present them in a logical fashion, and make decisions for improvement.

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Why is critical thinking important?

Critical thinking is useful in many areas of your life, including your career. It makes you a well-rounded individual, one who has looked at all of their options and possible solutions before making a choice.

According to the University of the People in California, having critical thinking skills is important because they are [ 1 ]:

Crucial for the economy

Essential for improving language and presentation skills

Very helpful in promoting creativity

Important for self-reflection

The basis of science and democracy 

Critical thinking skills are used every day in a myriad of ways and can be applied to situations such as a CEO approaching a group project or a nurse deciding in which order to treat their patients.

Examples of common critical thinking skills

Critical thinking skills differ from individual to individual and are utilized in various ways. Examples of common critical thinking skills include:

Identification of biases: Identifying biases means knowing there are certain people or things that may have an unfair prejudice or influence on the situation at hand. Pointing out these biases helps to remove them from contention when it comes to solving the problem and allows you to see things from a different perspective.

Research: Researching details and facts allows you to be prepared when presenting your information to people. You’ll know exactly what you’re talking about due to the time you’ve spent with the subject material, and you’ll be well-spoken and know what questions to ask to gain more knowledge. When researching, always use credible sources and factual information.

Open-mindedness: Being open-minded when having a conversation or participating in a group activity is crucial to success. Dismissing someone else’s ideas before you’ve heard them will inhibit you from progressing to a solution, and will often create animosity. If you truly want to solve a problem, you need to be willing to hear everyone’s opinions and ideas if you want them to hear yours.

Analysis: Analyzing your research will lead to you having a better understanding of the things you’ve heard and read. As a true critical thinker, you’ll want to seek out the truth and get to the source of issues. It’s important to avoid taking things at face value and always dig deeper.

Problem-solving: Problem-solving is perhaps the most important skill that critical thinkers can possess. The ability to solve issues and bounce back from conflict is what helps you succeed, be a leader, and effect change. One way to properly solve problems is to first recognize there’s a problem that needs solving. By determining the issue at hand, you can then analyze it and come up with several potential solutions.

How to develop critical thinking skills

You can develop critical thinking skills every day if you approach problems in a logical manner. Here are a few ways you can start your path to improvement:

1. Ask questions.

Be inquisitive about everything. Maintain a neutral perspective and develop a natural curiosity, so you can ask questions that develop your understanding of the situation or task at hand. The more details, facts, and information you have, the better informed you are to make decisions.

2. Practice active listening.

Utilize active listening techniques, which are founded in empathy, to really listen to what the other person is saying. Critical thinking, in part, is the cognitive process of reading the situation: the words coming out of their mouth, their body language, their reactions to your own words. Then, you might paraphrase to clarify what they're saying, so both of you agree you're on the same page.

3. Develop your logic and reasoning.

This is perhaps a more abstract task that requires practice and long-term development. However, think of a schoolteacher assessing the classroom to determine how to energize the lesson. There's options such as playing a game, watching a video, or challenging the students with a reward system. Using logic, you might decide that the reward system will take up too much time and is not an immediate fix. A video is not exactly relevant at this time. So, the teacher decides to play a simple word association game.

Scenarios like this happen every day, so next time, you can be more aware of what will work and what won't. Over time, developing your logic and reasoning will strengthen your critical thinking skills.

Learn tips and tricks on how to become a better critical thinker and problem solver through online courses from notable educational institutions on Coursera. Start with Introduction to Logic and Critical Thinking from Duke University or Mindware: Critical Thinking for the Information Age from the University of Michigan.

Article sources

University of the People, “ Why is Critical Thinking Important?: A Survival Guide , https://www.uopeople.edu/blog/why-is-critical-thinking-important/.” Accessed May 18, 2023.

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Argument and Argumentation

Argument is a central concept for philosophy. Philosophers rely heavily on arguments to justify claims, and these practices have been motivating reflections on what arguments and argumentation are for millennia. Moreover, argumentative practices are also pervasive elsewhere; they permeate scientific inquiry, legal procedures, education, and political institutions. The study of argumentation is an inter-disciplinary field of inquiry, involving philosophers, language theorists, legal scholars, cognitive scientists, computer scientists, and political scientists, among many others. This entry provides an overview of the literature on argumentation drawing primarily on philosophical sources, but also engaging extensively with relevant sources from other disciplines.

1. Terminological Clarifications

2.1 deduction, 2.2 induction, 2.3 abduction, 2.4 analogy, 2.5 fallacies, 3.1 adversarial and cooperative argumentation, 3.2 argumentation as an epistemic practice, 3.3 consensus-oriented argumentation, 3.4 argumentation and conflict management, 3.5 conclusion, 4.1 argumentation theory, 4.2 artificial intelligence and computer science, 4.3 cognitive science and psychology, 4.4 language and communication, 4.5 argumentation in specific social practices, 5.1 argumentative injustice and virtuous argumentation, 5.2 emotions and argumentation, 5.3 cross-cultural perspectives on argumentation, 5.4 argumentation and the internet, 6. conclusion, references for the main text, references for the historical supplement, other internet resources, related entries.

An argument can be defined as a complex symbolic structure where some parts, known as the premises, offer support to another part, the conclusion. Alternatively, an argument can be viewed as a complex speech act consisting of one or more acts of premising (which assert propositions in favor of the conclusion), an act of concluding, and a stated or implicit marker (“hence”, “therefore”) that indicates that the conclusion follows from the premises (Hitchcock 2007). [ 1 ] The relation of support between premises and conclusion can be cashed out in different ways: the premises may guarantee the truth of the conclusion, or make its truth more probable; the premises may imply the conclusion; the premises may make the conclusion more acceptable (or assertible).

For theoretical purposes, arguments may be considered as freestanding entities, abstracted from their contexts of use in actual human activities. But depending on one’s explanatory goals, there is also much to be gained from considering arguments as they in fact occur in human communicative practices. The term generally used for instances of exchange of arguments is argumentation . In what follows, the convention of using “argument” to refer to structures of premises and conclusion, and “argumentation” to refer to human practices and activities where arguments occur as communicative actions will be adopted.

Argumentation can be defined as the communicative activity of producing and exchanging reasons in order to support claims or defend/challenge positions, especially in situations of doubt or disagreement (Lewiński & Mohammed 2016). It is arguably best conceived as a kind of dialogue , even if one can also “argue” with oneself, in long speeches or in writing (in articles or books) for an intended but silent audience, or in groups rather than in dyads (Lewiński & Aakhus 2014). But argumentation is a special kind of dialogue: indeed, most of the dialogues we engage in are not instances of argumentation, for example when asking someone if they know what time it is, or when someone shares details about their vacation. Argumentation only occurs when, upon making a claim, someone receives a request for further support for the claim in the form of reasons, or estimates herself that further justification is required (Jackson & Jacobs 1980; Jackson, 2019). In such cases, dialogues of “giving and asking for reasons” ensue (Brandom, 1994; Bermejo Luque 2011). Since most of what we know we learn from others, argumentation seems to be an important mechanism to filter the information we receive, instead of accepting what others tell us uncritically (Sperber, Clément, et al. 2010).

The study of arguments and argumentation is also closely connected to the study of reasoning , understood as the process of reaching conclusions on the basis of careful, reflective consideration of the available information, i.e., by an examination of reasons . According to a widespread view, reasoning and argumentation are related (as both concern reasons) but fundamentally different phenomena: reasoning would belong to the mental realm of thinking—an individual inferring new information from the available information by means of careful consideration of reasons—whereas argumentation would belong to the public realm of the exchange of reasons, expressed in language or other symbolic media and intended for an audience. However, a number of authors have argued for a different view, namely that reasoning and argumentation are in fact two sides of the same coin, and that what is known as reasoning is by and large the internalization of practices of argumentation (MacKenzie 1989; Mercier & Sperber 2017; Mercier 2018). For the purposes of this entry, we can assume a close connection between reasoning and argumentation so that relevant research on reasoning can be suitably included in the discussions to come.

2. Types of Arguments

Arguments come in many kinds. In some of them, the truth of the premises is supposed to guarantee the truth of the conclusion, and these are known as deductive arguments. In others, the truth of the premises should make the truth of the conclusion more likely while not ensuring complete certainty; two well-known classes of such arguments are inductive and abductive arguments (a distinction introduced by Peirce, see entry on C.S. Peirce ). Unlike deduction, induction and abduction are thought to be ampliative: the conclusion goes beyond what is (logically) contained in the premises. Moreover, a type of argument that features prominently across different philosophical traditions, and yet does not fit neatly into any of the categories so far discussed, are analogical arguments. In this section, these four kinds of arguments are presented. The section closes with a discussion of fallacious arguments, that is, arguments that seem legitimate and “good”, but in fact are not. [ 2 ]

Valid deductive arguments are those where the truth of the premises necessitates the truth of the conclusion: the conclusion cannot but be true if the premises are true. Arguments having this property are said to be deductively valid . A valid argument whose premises are also true is said to be sound . Examples of valid deductive arguments are the familiar syllogisms, such as:

All humans are living beings. All living beings are mortal. Therefore, all humans are mortal.

In a deductively valid argument, the conclusion will be true in all situations where the premises are true, with no exceptions. A slightly more technical gloss of this idea goes as follows: in all possible worlds where the premises hold, the conclusion will also hold. This means that, if I know the premises of a deductively valid argument to be true of a given situation, then I can conclude with absolute certainty that the conclusion is also true of that situation. An important property typically associated with deductive arguments (but with exceptions, such as in relevant logic), and which differentiates them from inductive and abductive arguments, is the property of monotonicity : if premises A and B deductively imply conclusion C , then the addition of any arbitrary premise D will not invalidate the argument. In other words, if the argument “ A and B ; therefore C ” is deductively valid, then the argument “ A , B and D ; therefore C ” is equally deductively valid.

Deductive arguments are the objects of study of familiar logical systems such as (classical) propositional and predicate logic, as well as of subclassical systems such as intuitionistic and relevant logics (although in relevant logic the property of monotonicity does not hold, as it may lead to violations of criteria of relevance between premises and conclusion—see entry on relevance logic ). In each of these systems, the relation of logical consequence in question satisfies the property of necessary truth-preservation (see entry on logical consequence ). This is not surprising, as these systems were originally designed to capture arguments of a very specific kind, namely mathematical arguments (proofs), in the pioneering work of Frege, Russell, Hilbert, Gentzen, and others. Following a paradigm established in ancient Greek mathematics and famously captured in Euclid’s Elements , argumentative steps in mathematical proofs (in this tradition at least) must have the property of necessary truth preservation (Netz 1999). This paradigm remained influential for millennia, and still codifies what can be described as the “classical” conception of mathematical proof (Dutilh Novaes 2020a), even if practices of proof are ultimately also quite diverse. (In fact, there is much more to argumentation in mathematics than just deductive argumentation [Aberdein & Dove 2013].)

However, a number of philosophers have argued that deductive validity and necessary truth preservation in fact come apart. Some have reached this conclusion motivated by the familiar logical paradoxes such as the Liar or Curry’s paradox (Beall 2009; Field 2008; see entries on the Liar paradox and on Curry’s paradox ). Others have defended the idea that there are such things as contingent logical truths (Kaplan 1989; Nelson & Zalta 2012), which thus challenge the idea of necessary truth preservation. It has also been suggested that what is preserved in the transition from premises to conclusions in deductive arguments is in fact warrant or assertibility rather than truth (Restall 2004). Yet others, such as proponents of preservationist approaches to paraconsistent logic, posit that what is preserved by the deductive consequence relation is the coherence, or incoherence, of a set of premises (Schotch, Brown, & Jennings 2009; see entry on paraconsistent logic ). Nevertheless, it is fair to say that the view that deductive validity is to be understood primarily in terms of necessary truth preservation is still the received view.

Relatedly, there are a number of pressing philosophical issues pertaining to the justification of deduction, such as the exact nature of the necessity involved in deduction (metaphysical, logical, linguistic, epistemic; Shapiro 2005), and the possibility of offering a non-circular foundation for deduction (Dummett 1978). Furthermore, it is often remarked that the fact that a deductive argument is not ampliative may entail that it cannot be informative, which in turn would mean that its usefulness is quite limited; this problem has been described as “the scandal of deduction” (Sequoiah-Grayson 2008).

Be that as it may, deductive arguments have occupied a special place in philosophy and the sciences, ever since Aristotle presented the first fully-fledged theory of deductive argumentation and reasoning in the Prior Analytics (and the corresponding theory of scientific demonstration in the Posterior Analytics ; see Historical Supplement ). The fascination for deductive arguments is understandable, given their allure of certainty and indubitability. The more geometrico (a phrase introduced by Spinoza to describe the argumentative structure of his Ethics as following “a geometrical style”—see entry on Spinoza ) has been influential in many fields other than mathematics. However, the focus on deductive arguments at the expense of other types of arguments has arguably skewed investigations on argument and argumentation too much in one specific direction (see (Bermejo-Luque 2020) for a critique of deductivism in the study of argumentation).

In recent decades, the view that everyday reasoning and argumentation by and large do not follow the canons of deductive argumentation has been gaining traction. In psychology of reasoning, Oaksford and Chater were the first to argue already in the 1980s that human reasoning “in the wild” is essentially probabilistic, following the basic canons of Bayesian probabilities (Oaksford & Chater 2018; Elqayam 2018; see section 5.3 below). Computer scientists and artificial intelligence researchers have also developed a strong interest in non-monotonic reasoning and argumentation (Reiter 1980), recognizing that, outside specific scientific contexts, human reasoning tends to be deeply defeasible (Pollock 1987; see entries on non-monotonic logic and defeasible reasoning ). Thus seen, deductive argumentation might be considered as the exception rather than the rule in human argumentative practices taken as a whole (Dutilh Novaes 2020a). But there are others, especially philosophers, who still maintain that the use of deductive reasoning and argumentation is widespread and extends beyond niches of specialists (Shapiro 2014; Williamson 2018).

Inductive arguments are arguments where observations about past instances and regularities lead to conclusions about future instances and general principles. For example, the observation that the sun has risen in the east every single day until now leads to the conclusion that it will rise in the east tomorrow, and to the general principle “the sun always rises in the east”. Generally speaking, inductive arguments are based on statistical frequencies, which then lead to generalizations beyond the sample of cases initially under consideration: from the observed to the unobserved. In a good, i.e., cogent , inductive argument, the truth of the premises provides some degree of support for the truth of the conclusion. In contrast with a deductively valid argument, in an inductive argument the degree of support will never be maximal, as there is always the possibility of the conclusion being false given the truth of the premises. A gloss in terms of possible worlds might be that, while in a deductively valid argument the conclusion will hold in all possible worlds where the premises hold, in a good inductive argument the conclusion will hold in a significant proportion of the possible worlds where the premises hold. The proportion of such worlds may give a measure of the strength of support of the premises for the conclusion (see entry on inductive logic ).

Inductive arguments have been recognized and used in science and elsewhere for millennia. The concept of induction ( epagoge in Greek) was understood by Aristotle as a progression from particulars to a universal, and figured prominently both in his conception of the scientific method and in dialectical practices (see entry on Aristotle’s logic, section 3.1 ). However, a deductivist conception of the scientific method remained overall more influential in Aristotelian traditions, inspired by the theory of scientific demonstration of the Posterior Analytics . It is only with the so-called “scientific revolution” of the early modern period that experiments and observation of individual cases became one of the pillars of scientific methodology, a transition that is strongly associated with the figure of Francis Bacon (1561–1626; see entry on Francis Bacon ).

Inductive inferences/arguments are ubiquitous both in science and in everyday life, and for the most part quite reliable. The functioning of the world around us seems to display a fair amount of statistical regularity, and this is referred to as the “Uniformity Principle” in the literature on the problem of induction (to be discussed shortly). Moreover, it has been argued that generalizing from previously observed frequencies is the most basic principle of human cognition (Clark 2016).

However, it has long been recognized that inductive inferences/arguments are not unproblematic. Hume famously offered the first influential formulation of what became known as “the problem of induction” in his Treatise of Human Nature (see entries on David Hume and on the problem of induction ; Howson 2000). Hume raises the question of what grounds the correctness of inductive inferences/arguments, and posits that there must be an argument establishing the validity of the Uniformity Principle for inductive inferences to be truly justified. He goes on to argue that this argument cannot be deductive, as it is not inconceivable that the course of nature may change. But it cannot be probable either, as probable arguments already presuppose the validity of the Uniformity Principle; circularity would ensue. Since these are the only two options, he concludes that the Uniformity Principle cannot be established by rational argument, and hence that induction cannot be justified.

A more recent influential critique of inductive arguments is the one offered in (Harman 1965). Harman argues that either enumerative induction is not always warranted, or it is always warranted but constitutes an uninteresting special case of the more general category of inference to the best explanation (see next section). The upshot is that, for Harman, induction should not be considered a warranted form of inference in its own right.

Given the centrality of induction for scientific practice, there have been numerous attempts to respond to the critics of induction, with various degrees of success. Among those, an influential recent response to the problem of induction is Norton’s material theory of induction (Norton 2003). But the problem has not prevented scientists and laypeople alike from continuing to use induction widely. More recently, the use of statistical frequencies for social categories to draw conclusions about specific individuals has become a matter of contention, both at the individual level (see entry on implicit bias ) and at the institutional level (e.g., the use of predictive algorithms for law enforcement [Jorgensen Bolinger 2021]). These debates can be seen as reoccurrences of Hume’s problem of induction, now in the domain of social rather than of natural phenomena.

An abductive argument is one where, from the observation of a few relevant facts, a conclusion is drawn as to what could possibly explain the occurrence of these facts (see entry on abduction ). Abduction is widely thought to be ubiquitous both in science and in everyday life, as well as in other specific domains such as the law, medical diagnosis, and explainable artificial intelligence (Josephson & Josephson 1994). Indeed, a good example of abduction is the closing argument by a prosecutor in a court of law who, after summarizing the available evidence, concludes that the most plausible explanation for it is that the defendant must have committed the crime they are accused of.

Like induction, and unlike deduction, abduction is not necessarily truth-preserving: in the example above, it is still possible that the defendant is not guilty after all, and that some other, unexpected phenomena caused the evidence to emerge. But abduction is significantly different from induction in that it does not only concern the generalization of prior observation for prediction (though it may also involve statistical data): rather, abduction is often backward-looking in that it seeks to explain something that has already happened. The key notion is that of bringing together apparently independent phenomena or events as explanatorily and/or causally connected to each other, something that is absent from a purely inductive argument that only appeals to observed frequencies. Cognitively, abduction taps into the well-known human tendency to seek (causal) explanations for phenomena (Keil 2006).

As noted, deduction and induction have been recognized as important classes of arguments for millennia; the concept of abduction is by comparison a latecomer. It is important to notice though that explanatory arguments as such are not latecomers; indeed, Aristotle’s very conception of scientific demonstration is based on the concept of explaining causes (see entry on Aristotle ). What is recent is the conceptualization of abduction as a special class of arguments, and the term itself. The term was introduced by Peirce as a third class of inferences distinct from deduction and induction: for Peirce, abduction is understood as the process of forming explanatory hypotheses, thus leading to new ideas and concepts (whereas for him deduction and induction could not lead to new ideas or theories; see the entry on Peirce ). Thus seen, abduction pertains to contexts of discovery , in which case it is not clear that it corresponds to instances of arguments, properly speaking. In its modern meaning, however, abduction pertains to contexts of justification , and thus to speak of abductive arguments becomes appropriate. An abductive argument is now typically understood as an inference to the best explanation (Lipton 1971 [2003]), although some authors contend that there are good reasons to distinguish the two concepts (Campos 2011).

While the main ideas behind abduction may seem simple enough, cashing out more precisely how exactly abduction works is a complex matter (see entry on abduction ). Moreover, it is not clear that abductive arguments are always or even generally reliable and cogent. Humans seem to have a tendency to overshoot in their quest for causal explanations, and often look for simplicity where there is none to be found (Lombrozo 2007; but see Sober 2015 on the significance of parsimony in scientific reasoning). There are also a number of philosophical worries pertaining to the justification of abduction, especially in scientific contexts; one influential critique of abduction/inference to the best explanation is the one articulated by van Fraassen (Fraassen 1989). A frequent concern pertains to the connection between explanatory superiority and truth: are we entitled to conclude that the conclusion of an abductive argument is true solely on the basis of it being a good (or even the best) explanation for the phenomena in question? It seems that no amount of philosophical a priori theorizing will provide justification for the leap from explanatory superiority to truth. Instead, defenders of abduction tend to offer empirical arguments showing that abduction tends to be a reliable rule of inference. In this sense, abduction and induction are comparable: they are widely used, grounded in very basic human cognitive tendencies, but they give rise to a number of difficult philosophical problems.

Arguments by analogy are based on the idea that, if two things are similar, what is true of one of them is likely to be true of the other as well (see entry on analogy and analogical reasoning ). Analogical arguments are widely used across different domains of human activity, for example in legal contexts (see entry on precedent and analogy in legal reasoning ). As an example, take an argument for the wrongness of farming non-human animals for food consumption: if an alien species farmed humans for food, that would be wrong; so, by analogy, it is wrong for us humans to farm non-human animals for food. The general idea is captured in the following schema (adapted from the entry on analogy and analogical reasoning ; S is the source domain and T the target domain of the analogy):

• S is similar to T in certain (known) respects.
• S has some further feature Q .
• Therefore, T also has the feature Q , or some feature Q * similar to Q .

The first premise establishes the analogy between two situations, objects, phenomena etc. The second premise states that the source domain has a given property. The conclusion is then that the target domain also has this property, or a suitable counterpart thereof. While informative, this schema does not differentiate between good and bad analogical arguments, and so does not offer much by way of explaining what grounds (good) analogical arguments. Indeed, contentious cases usually pertain to premise 1, and in particular to whether S and T are sufficiently similar in a way that is relevant for having or not having feature Q .

Analogical arguments are widely present in all known philosophical traditions, including three major ancient traditions: Greek, Chinese, and Indian (see Historical Supplement ). Analogies abound in ancient Greek philosophical texts, for example in Plato’s dialogues. In the Gorgias , for instance, the knack of rhetoric is compared to pastry-baking—seductive but ultimately unhealthy—whereas philosophy would correspond to medicine—potentially painful and unpleasant but good for the soul/body (Irani 2017). Aristotle discussed analogy extensively in the Prior Analytics and in the Topics (see section 3.2 of the entry on analogy and analogical reasoning ). In ancient Chinese philosophy, analogy occupies a very prominent position; indeed, it is perhaps the main form of argumentation for Chinese thinkers. Mohist thinkers were particularly interested in analogical arguments (see entries on logic and language in early Chinese philosophy , Mohism and the Mohist canons ). In the Latin medieval tradition too analogy received sustained attention, in particular in the domains of logic, theology and metaphysics (see entry on medieval theories of analogy ).

Analogical arguments continue to occupy a central position in philosophical discussions, and a number of the most prominent philosophical arguments of the last decades are analogical arguments, e.g., Jarvis Thomson’s violinist argument purportedly showing the permissibility of abortion (Thomson 1971), and Searle’s Chinese Room argument purportedly showing that computers cannot display real understanding (see entry on the Chinese Room argument ). (Notice that these two arguments are often described as thought experiments [see entry on thought experiments ], but thought experiments are often based on analogical principles when seeking to make a point that transcends the thought experiment as such.) The Achilles’ heel of analogical arguments can be illustrated by these two examples: both arguments have been criticized on the grounds that the purported similarity between the source and the target domains is not sufficient to extrapolate the property of the source domain (the permissibility of disconnecting from the violinist; the absence of understanding in the Chinese room) to the target domain (abortion; digital computers and artificial intelligence).

In sum, while analogical arguments in general perhaps confer a lesser degree of conviction than the other three kinds of arguments discussed, they are widely used both in professional circles and in everyday life. They have rightly attracted a fair amount of attention from scholars in different disciplines, and remain an important object of study (see entry on analogy and analogical reasoning ).

One of the most extensively studied types of arguments throughout the centuries are, perhaps surprisingly, arguments that appear legitimate but are not, known as fallacious arguments . From early on, the investigation of such arguments occupied a prominent position in Aristotelian logical traditions, inspired in particular by his book Sophistical Refutations (see Historical Supplement ). The thought is that, to argue well, it is not sufficient to be able to produce and recognize good arguments; it is equally (or perhaps even more) important to be able to recognize bad arguments by others, and to avoid producing bad arguments oneself. This is particularly true of the tricky cases, namely arguments that appear legitimate but are not, i.e., fallacies.

Some well-know types of fallacies include (see entry on fallacies for a more extensive discussion):

• The fallacy of equivocation, which occurs when an arguer exploits the ambiguity of a term or phrase which has occurred at least twice in an argument to draw an unwarranted conclusion.
• The fallacy of begging the question, when one of the premises and the conclusion of an argument are the same proposition, but differently formulated.
• The fallacy of appeal to authority, when a claim is supported by reference to an authority instead of offering reasons to support it.
• The ad hominem fallacy, which involves bringing negative aspects of an arguer, or their situation, to argue against the view they are advancing.
• The fallacy of faulty analogy, when an analogy is used as an argument but there is not sufficient relevant similarity between the source domain and the target domain (as discussed above).

Beyond their (presumed?) usefulness in teaching argumentative skills, the literature on fallacies raises a number of important philosophical discussions, such as: What determines when an argument is fallacious or rather a legitimate argument? (See section 4.3 below on Bayesian accounts of fallacies) What causes certain arguments to be fallacious? Is the focus on fallacies a useful approach to arguments at all? (Massey 1981) Despite the occasional criticism, the concept of fallacies remains central in the study of arguments and argumentation.

3. Types of Argumentation

Just as there are different types of arguments, there are different types of argumentative situations, depending on the communicative goals of the persons involved and background conditions. Argumentation may occur when people are trying to reach consensus in a situation of dissent, but it may also occur when scientists discuss their findings with each other (to name but two examples). Specific rules of argumentative engagement may vary depending on these different types of argumentation.

A related point extensively discussed in the recent literature pertains to the function(s) of argumentation. [ 3 ] What’s the point of arguing? While it is often recognized that argumentation may have multiple functions, different authors tend to emphasize specific functions for argumentation at the expense of others. This section offers an overview of discussions on types of argumentation and its functions, demonstrating that argumentation is a multifaceted phenomenon that has different applications in different circumstances.

A question that has received much attention in the literature of the past decades pertains to whether the activity of argumentation is primarily adversarial or primarily cooperative. This question in fact corresponds to two sub-questions: the descriptive question of whether instances of argumentation are on the whole primarily adversarial or cooperative; and the normative question of whether argumentation should be (primarily) adversarial or cooperative. A number of authors have answered “adversarial” to the descriptive question and “cooperative” to the normative question, thus identifying a discrepancy between practices and normative ideals that must be remedied (or so they claim; Cohen 1995).

A case in point: recently, a number of far-right Internet personalities have advocated the idea that argumentation can be used to overpower one’s opponents, as described in the book The Art of the Argument: Western Civilization’s Last Stand (2017) by the white supremacist S. Molyneux. Such aggressive practices reflect a vision of argumentation as a kind of competition or battle, where the goal is to “score points” and “beat the opponent”. Authors who have criticized (overly) adversarial practices of argumentation include (Moulton 1983; Gilbert 1994; Rooney 2012; Hundleby 2013; Bailin & Battersby 2016). Many (but not all) of these authors formulated their criticism specifically from a feminist perspective (see entry on feminist perspectives on argumentation ).

Feminist critiques of adversarial argumentation challenge ideals of argumentation as a form of competition, where masculine-coded values of aggression and violence prevail (Kidd 2020). For these authors, such ideals encourage argumentative performances where excessive use of forcefulness is on display. Instances of aggressive argumentation in turn have a number of problematic consequences: epistemic consequences—the pursuit of truth is not best served by adversarial argumentation—as well as moral/ethical/political consequences—these practices exclude a number of people from participating in argumentative encounters, namely those for whom displays of aggression do not constitute socially acceptable behavior (women and other socially disadvantaged groups in particular). These authors defend alternative conceptions of argumentation as a cooperative, nurturing activity (Gilbert 1994; Bailin & Battersby 2016), which are traditionally feminine-coded values. Crucially, they view adversarial conceptions of argumentation as optional , maintaining that the alternatives are equally legitimate and that cooperative conceptions should be adopted and cultivated.

By contrast, others have argued that adversariality, when suitably understood, can be seen as an integral and in fact desirable component of argumentation (Govier 1999; Aikin 2011; Casey 2020; but notice that these authors each develop different accounts of adversariality in argumentation). Such authors answer “adversarial” both to the descriptive and to the normative questions stated above. One overall theme is the need to draw a distinction between (excessive) aggressiveness and adversariality as such. Govier, for example, distinguishes between ancillary (negative) adversariality and minimal adversariality (Govier 1999). The thought is that, while the feminist critique of excessive aggression in argumentation is well taken, adversariality conceived and practiced in different ways need not have the detrimental consequences of more extreme versions of belligerent argumentation. Moreover, for these authors, adversariality in argumentation is simply not optional: it is an intrinsic feature of argumentative practices, but these practices also require a background of cooperation and agreement regarding, e.g., the accepted rules of inference.

But ultimately, the presumed opposition between adversarial and cooperative conceptions of argumentation may well be merely apparent. It may be argued for example that actual argumentative encounters ought to be adversarial or cooperative to different degrees, as different types of argumentation are required for different situations (Dutilh Novaes forthcoming). Indeed, perhaps we should not look for a one-fits-all model of how argumentation ought to be conducted across different contexts and situation, given the diversity of uses of argumentation.

We speak of argumentation as an epistemic practice when we take its primary purpose to be that of improving our beliefs and increasing knowledge, or of fostering understanding. To engage in argumentation can be a way to acquire more accurate beliefs: by examining critically reasons for and against a given position, we would be able to weed out weaker, poorly justified beliefs (likely to be false) and end up with stronger, suitably justified beliefs (likely to be true). From this perspective, the goal of engaging in argumentation is to learn , i.e., to improve one’s epistemic position (as opposed to argumentation “to win” (Fisher & Keil 2016)). Indeed, argumentation is often said to be truth-conducive (Betz 2013).

The idea that argumentation can be an epistemically beneficial process is as old as philosophy itself. In every major historical philosophical tradition, argumentation is viewed as an essential component of philosophical reflection precisely because it may be used to aim at the truth (indeed this is the core of Plato’s critique of the Sophists and their excessive focus on persuasion at the expense of truth (Irani 2017; see Historical Supplement ). Recent proponents of an epistemological approach to argumentation include (Goldman 2004; Lumer 2005; Biro & Siegel 2006). Alvin Goldman captures this general idea in the following terms:

Norms of good argumentation are substantially dedicated to the promotion of truthful speech and the exposure of falsehood, whether intentional or unintentional. […] Norms of good argumentation are part of a practice to encourage the exchange of truths through sincere, non-negligent, and mutually corrective speech. (Goldman 1994: 30)

Of course, it is at least in theory possible to engage in argumentation with oneself along these lines, solitarily weighing the pros and cons of a position. But a number of philosophers, most notably John Stuart Mill, maintain that interpersonal argumentative situations, involving people who truly disagree with each other, work best to realize the epistemic potential of argumentation to improve our beliefs (a point he developed in On Liberty (1859; see entry on John Stuart Mill ). When our ideas are challenged by engagement with those who disagree with us, we are forced to consider our own beliefs more thoroughly and critically. The result is that the remaining beliefs, those that have survived critical challenge, will be better grounded than those we held before such encounters. Dissenters thus force us to stay epistemically alert instead of becoming too comfortable with existing, entrenched beliefs. On this conception, arguers cooperate with each other precisely by being adversarial, i.e., by adopting a critical stance towards the positions one disagrees with.

The view that argumentation aims at epistemic improvement is in many senses appealing, but it is doubtful that it reflects the actual outcomes of argumentation in many real-life situations. Indeed, it seems that, more often than not, we are not Millians when arguing: we do not tend to engage with dissenting opinions with an open mind. Indeed, there is quite some evidence suggesting that arguments are in fact not a very efficient means to change minds in most real-life situations (Gordon-Smith 2019). People typically do not like to change their minds about firmly entrenched beliefs, and so when confronted with arguments or evidence that contradict these beliefs, they tend to either look away or to discredit the source of the argument as unreliable (Dutilh Novaes 2020c)—a phenomenon also known as “confirmation bias” (Nickerson 1998).

In particular, arguments that threaten our core beliefs and our sense of belonging to a group (e.g., political beliefs) typically trigger all kinds of motivated reasoning (Taber & Lodge 2006; Kahan 2017) whereby one outright rejects those arguments without properly engaging with their content. Relatedly, when choosing among a vast supply of options, people tend to gravitate towards content and sources that confirm their existing opinions, thus giving rise to so-called “echo chambers” and “epistemic bubbles” (Nguyen 2020). Furthermore, some arguments can be deceptively convincing in that they look valid but are not (Tindale 2007; see entry on fallacies ). Because most of us are arguably not very good at spotting fallacious arguments, especially if they are arguments that lend support to the beliefs we already hold, engaging in argumentation may in fact decrease the accuracy of our beliefs by persuading us of false conclusions with incorrect arguments (Fantl 2018).

In sum, despite the optimism of Mill and many others, it seems that engaging in argumentation will not automatically improve our beliefs (even if this may occur in some circumstances). [ 4 ] However, it may still be argued that an epistemological approach to argumentation can serve the purpose of providing a normative ideal for argumentative practices, even if it is not always a descriptively accurate account of these practices in the messy real world. Moreover, at least some concrete instances of argumentation, in particular argumentation in science (see section 4.5 below) seem to offer successful examples of epistemic-oriented argumentative practices.

Another important strand in the literature on argumentation are theories that view consensus as the primary goal of argumentative processes: to eliminate or resolve a difference of (expressed) opinion. The tradition of pragma-dialectics is a prominent recent exponent of this strand (Eemeren & Grootendorst 2004). These consensus-oriented approaches are motivated by the social complexity of human life, and the attribution of a role of social coordination to argumentation. Because humans are social animals who must often cooperate with other humans to successfully accomplish certain tasks, they must have mechanisms to align their beliefs and intentions, and subsequently their actions (Tomasello 2014). The thought is that argumentation would be a particularly suitable mechanism for such alignment, as an exchange of reasons would make it more likely that differences of opinion would decrease (Norman 2016). This may happen precisely because argumentation would be a good way to track truths and avoid falsehoods, as discussed in the previous section; by being involved in the same epistemic process of exchanging reasons, the participants in an argumentative situation would all come to converge towards the truth, and thus the upshot would be that they also come to agree with each other. However, consensus-oriented views need not presuppose that argumentation is truth-conducive: the ultimate goal of such instances of argumentation is that of social coordination, and for this tracking truth is not a requirement (Patterson 2011).

In particular, the very notion of deliberative democracy is viewed as resting crucially on argumentative practices that aim for consensus (Fishkin 2016; see entry on democracy ). (For present purposes, “deliberation” and “argumentation” can be treated as roughly synonymous). In a deliberative democracy, for a decision to be legitimate, it must be preceded by authentic public deliberation—a discussion of the pros and cons of the different options—not merely the aggregation of preferences that occurs in voting. Moreover, in democratic deliberation, when full consensus does not emerge, the parties involved may opt for a compromise solution, e.g., a coalition-based political system.

A prominent theorist of deliberative democracy thus understood is Jürgen Habermas, whose “discourse theory of law and democracy” relies heavily on practices of political justification and argumentation taking place in what he calls “the public sphere” (Habermas 1992 [1996]; 1981 [1984]; see entry on Habermas ). He starts from the idea that politics allows for the collective organization of people’s lives, including the common rules they will live by. Political argumentation is a form of communicative practice, so general assumptions for communicative practices in general apply. However, additional assumptions apply as well (Olson 2011 [2014]). In particular, deliberating participants must accept that anyone can participate in these discursive practices (democratic deliberation should be inclusive), and that anyone can introduce and challenge claims that are made in the public sphere (democratic deliberation should be free). They must also see one another as having equal status, at least for the purposes of deliberation (democratic deliberation should be equal). In turn, critics of Habermas’s account view it as unrealistic, as it presupposes an ideal situation where all citizens are treated equally and engage in public debates in good faith (Mouffe 1999; Geuss 2019).

More generally, it seems that it is only under quite specific conditions that argumentation reliably leads to consensus (as also suggested by formal modeling of argumentative situations (Betz 2013; Olsson 2013; Mäs & Flache 2013)). Consensus-oriented argumentation seems to work well in cooperative contexts, but not so much in situations of conflict (Dutilh Novaes forthcoming). In particular, the discussing parties must already have a significant amount of background agreement—especially agreement on what counts as a legitimate argument or compelling evidence—for argumentation and deliberation to lead to consensus. Especially in situations of deep disagreement (Fogelin 1985), it seems that the potential of argumentation to lead to consensus is quite limited. Instead, in many real-life situations, argumentation often leads to the opposite result; people disagree with each other even more after engaging in argumentation (Sunstein 2002). This is the well-documented phenomenon of group polarization , which occurs when an initial position or tendency of individual members of a group becomes more extreme after group discussion (Isenberg 1986).

In fact, it may be argued that argumentation will often create or exacerbate conflict and adversariality, rather than leading to the resolution of differences of opinions. Furthermore, a focus on consensus may end up reinforcing and perpetuating existing unequal power relations in a society.

In an unjust society, what purports to be a cooperative exchange of reasons really perpetuates patterns of oppression. (Goodwin 2007: 77)

This general point has been made by a number of political thinkers (e.g., Young 2000), who have highlighted the exclusionary implications of consensus-oriented political deliberation. The upshot is that consensus may not only be an unrealistic goal for argumentation; it may not even be a desirable goal for argumentation in a number of situations (e.g., when there is great power imbalance). Despite these concerns, the view that the primary goal of argumentation is to aim for consensus remains influential in the literature.

Finally, a number of authors have attributed to argumentation the potential to manage (pre-existing) conflict. In a sense, the consensus-oriented view of argumentation just discussed is a special case of conflict management argumentation, based on the assumption that the best way to manage conflict and disagreement is to aim for consensus and thus eliminate conflict. But conflict can be managed in different ways, not all of them leading to consensus; indeed, some authors maintain that argumentation may help mitigate conflict even when the explicit aim is not that of reaching consensus. Importantly, authors who identify conflict management (or variations thereof) as a function for argumentation differ in their overall appreciation of the value of argumentation: some take it to be at best futile and at worst destructive, [ 5 ] while others attribute a more positive role to argumentation in conflict management.

To this category also belong the conceptualizations of argumentation-as-war discussed (and criticized) by a number of authors (Cohen 1995; Bailin & Battersby 2016); in such cases, conflict is not so much managed but rather enacted (and possibly exacerbated) by means of argumentation. Thus seen, the function of argumentation would not be fundamentally different from the function of organized competitive activities such as sports or even war (with suitable rules of engagement; Aikin 2011).

When conflict emerges, people have various options: they may choose not to engage and instead prefer to flee; they may go into full-blown fighting mode, which may include physical aggression; or they may opt for approaches somewhere in between the fight-or-flee extremes of the spectrum. Argumentation can be plausibly classified as an intermediary response:

[A]rgument literally is a form of pacifism—we are using words instead of swords to settle our disputes. With argument, we settle our disputes in ways that are most respectful of those who disagree—we do not buy them off, we do not threaten them, and we do not beat them into submission. Instead, we give them reasons that bear on the truth or falsity of their beliefs. However adversarial argument may be, it isn’t bombing. […] argument is a pacifistic replacement for truly violent solutions to disagreements…. (Aikin 2011: 256)

This is not to say that argumentation will always or even typically be the best approach to handle conflict and disagreement; the point is rather that argumentation at least has the potential to do so, provided that the background conditions are suitable and that provisions to mitigate escalation are in place (Aikin 2011). Versions of this view can be found in the work of proponents of agonistic conceptions of democracy and political deliberation (Wenman 2013; see entry on feminist political philosophy ). For agonist thinkers, conflict and strife are inevitable features of human lives, and so cannot be eliminated; but they can be managed. One of them is Chantal Mouffe (Mouffe 2000), for whom democratic practices, including argumentation/deliberation, can serve to contain hostility and transform it into more constructive forms of contest. However, it is far from obvious that argumentation by itself will suffice to manage conflict; typically, other kinds of intervention must be involved (Young 2000), as the risk of argumentation being used to exercise power rather than as a tool to manage conflict always looms large (van Laar & Krabbe 2019).

From these observations on different types of argumentation, a pluralistic picture emerges: argumentation, understood as the exchange of reasons to justify claims, seems to have different applications in different situations. However, it is not clear that some of the goals often attributed to argumentation such as epistemic improvement and reaching consensus can in fact be reliably achieved in many real life situations. Does this mean that argumentation is useless and futile? Not necessarily, but it may mean that engaging in argumentation will not always be the optimal response in a number of contexts.

4. Argumentation Across Fields of Inquiry and Social Practices

Argumentation is practiced and studied in many fields of inquiry; philosophers interested in argumentation have much to benefit from engaging with these bodies of research as well.

To understand the emergence of argumentation theory as a specific field of research in the twentieth century, a brief discussion of preceding events is necessary. In the nineteenth century, a number of textbooks aiming to improve everyday reasoning via public education emphasized logical and rhetorical concerns, such as those by Richard Whately (see entry on fallacies ). As noted in section 3.2 , John Stuart Mill also had a keen interest in argumentation and its role in public discourse (Mill 1859), as well as an interest in logic and reasoning (see entries on Mill and on fallacies ). But with the advent of mathematical logic in the final decades of the nineteenth century, logic and the study of ordinary, everyday argumentation came apart, as logicians such as Frege, Hilbert, Russell etc. were primarily interested in mathematical reasoning and argumentation. As a result, their logical systems are not particularly suitable to study everyday argumentation, as this is simply not what they were designed to do. [ 6 ]

Nevertheless, in the twentieth century a number of authors took inspiration from developments in formal logic and expanded the use of logical tools to the analysis of ordinary argumentation. A pioneer in this tradition is Susan Stebbing, who wrote what can be seen as the first textbook in analytic philosophy, and then went on to write a number of books aimed at a general audience addressing everyday and public discourse from a philosophical/logical perspective (see entry on Susan Stebbing ). Her 1939 book Thinking to Some Purpose , which can be considered as one of the first textbooks in critical thinking, was widely read at the time, but did not become particularly influential for the development of argumentation theory in the decades to follow.

By contrast, Stephen Toulmin’s 1958 book The Uses of Argument has been tremendously influential in a wide range of fields, including critical thinking education, rhetoric, speech communication, and computer science (perhaps even more so than in Toulmin’s own original field, philosophy). Toulmin’s aim was to criticize the assumption (widely held by Anglo-American philosophers at the time) that any significant argument can be formulated in purely formal, deductive terms, using the formal logical systems that had emerged in the preceding decades (see (Eemeren, Garssen, et al. 2014: ch. 4). While this critique was met with much hostility among fellow philosophers, it eventually gave rise to an alternative way of approaching argumentation, which is often described as “informal logic” (see entry on informal logic ). This approach seeks to engage and analyze instances of argumentation in everyday life; it recognizes that, while useful, the tools of deductive logic alone do not suffice to investigate argumentation in all its complexity and pragmatic import. In a similar vein, Charles Hamblin’s 1970 book Fallacies reinvigorated the study of fallacies in the context of argumentation by re-emphasizing (following Aristotle) the importance of a dialectical-dialogical background when reflecting on fallacies in argumentation (see entry on fallacies ).

Around the same time as Toulmin, Chaïm Perelman and Lucie Olbrechts-Tyteca were developing an approach to argumentation that emphasized its persuasive component. To this end, they turned to classical theories of rhetoric, and adapted them to give rise to what they described as the “New Rhetoric”. Their book Traité de l’argumentation: La nouvelle rhétorique was published in 1958 in French, and translated into English in 1969. Its key idea:

since argumentation aims at securing the adherence of those to whom it is addressed, it is, in its entirety, relative to the audience to be influenced. (Perelman & Olbrechts-Tyteca 1958 [1969: 19])

They introduced the influential distinction between universal and particular audiences: while every argument is directed at a specific individual or group, the concept of a universal audience serves as a normative ideal encapsulating shared standards of agreement on what counts as legitimate argumentation (see Eemeren, Garssen, et al. 2014: ch. 5).

The work of these pioneers provided the foundations for subsequent research in argumentation theory. One approach that became influential in the following decades is the pragma-dialectics tradition developed by Frans van Eemeren and Rob Grootendorst (Eemeren & Grootendorst 1984, 2004). They also founded the journal Argumentation , one of the flagship journals in argumentation theory. Pragma-dialectics was developed to study argumentation as a discourse activity, a complex speech act that occurs as part of interactional linguistic activities with specific communicative goals (“pragma” refers to the functional perspective of goals, and “dialectic” to the interactive component). For these authors, argumentative discourse is primarily directed at the reasonable resolution of a difference of opinion. Pragma-dialectics has a descriptive as well as a normative component, thus offering tools both for the analysis of concrete instances of argumentation and for the evaluation of argumentation correctness and success (see Eemeren, Garssen, et al. 2014: ch. 10).

Another leading author in argumentation theory is Douglas Walton, who pioneered the argument schemes approach to argumentation that borrows tools from formal logic but expands them so as to treat a wider range of arguments than those covered by traditional logical systems (Walton, Reed, & Macagno 2008). Walton also formulated an influential account of argumentation in dialogue in collaboration with Erik Krabbe (Walton & Krabbe 1995). Ralph Johnson and Anthony Blair further helped to consolidate the field of argumentation theory and informal logic by founding the Centre for Research in Reasoning, Argumentation, and Rhetoric in Windsor (Ontario, Canada), and by initiating the journal Informal Logic . Their textbook Logical Self-Defense (Johnson & Blair 1977) has also been particularly influential.

The study of argumentation within computer science and artificial intelligence is a thriving field of research, with dedicated journals such as Argument and Computation and regular conference series such as COMMA (International Conference on Computational Models of Argument; see Rahwan & Simari 2009 and Eemeren, Garssen, et al. 2014: ch. 11 for overviews).

The historical roots of argumentation research in artificial intelligence can be traced back to work on non-monotonic logics (see entry on non-monotonic logics ) and defeasible reasoning (see entry on defeasible reasoning ). Since then, three main different perspectives have emerged (Eemeren, Garssen, et al. 2014: ch. 11): the theoretical systems perspective, where the focus is on theoretical and formal models of argumentation (following the tradition of philosophical and formal logic); the artificial systems perspective, where the aim is to build computer programs that model or support argumentative tasks, for instance, in online dialogue games or in expert systems; the natural systems perspective, which investigates argumentation in its natural form with the help of computational tools (e.g., argumentation mining [Peldszus & Stede 2013; Habernal & Gurevych 2017], where computational methods are used to identify argumentative structures in large corpora of texts).

An influential approach in this research tradition is that of abstract argumentation frameworks , initiated by the pioneering work of Dung (1995). Before that, argumentation in AI was studied mostly under the inspiration of concepts coming from informal logic such as argumentation schemes, context, stages of dialogues and argument moves. By contrast, the key notion in the framework proposed by Dung is that of argument attack , understood as an abstract formal relation roughly intended to capture the idea that it is possible to challenge an argument by means of another argument (assertions are understood as a special case of arguments with zero premises). Arguments can then be represented in networks of attacks and defenses: an argument A can attack an argument B , and B in turn may attack further arguments C and D (the connection with the notion of defeaters is a natural one, which Dung also addresses).

Besides abstract argumentation, three other important lines of research in AI are: the (internal) structure of arguments; argumentation in multi-agent systems; applications to specific tasks and domains (Rahwan & Siwari 2009). The structural approach investigates formally features such as argument strength/force (e.g., a conclusive argument is stronger than a defeasible argument), argument schemes (Bex, Prakken, Reed, & Walton 2003) etc. Argumentation in multi-agent systems is a thriving subfield with its own dedicated conference series (ArgMAS), based on the recognition that argumentation is a particularly suitable vehicle to facilitate interaction in the artificial environments studied by AI researchers working on multi-agent systems (see a special issue of the journal Argument & Computation [Atkinson, Cerutti, et al. 2016]). Finally, computational approaches in argumentation have also thrived with respect to specific domains and applications, such as legal argumentation (Prakken & Sartor 2015). Recently, as a reaction to the machine-learning paradigm, the idea of explainable AI has gotten traction, and the concept of argumentation is thought to play a fundamental role for explainable AI (Sklar & Azhar 2018).

Argumentation is also an important topic of investigation within cognitive science and psychology. Researchers in these fields are predominantly interested in the descriptive question of how people in fact engage in argumentation, rather than in the normative question of how they ought to do it (although some of them have also drawn normative conclusions, e.g., Hahn & Oaksford 2006; Hahn & Hornikx, 2016). Controlled experiments are one of the ways in which the descriptive question can be investigated.

Systematic research specifically on argumentation within cognitive science and psychology has significantly increased over the last 10 years. Before that, there had been extensive research on reasoning conceived as an individual, internal process, much of which had been conducted using task materials such as syllogistic arguments (Dutilh Novaes 2020b). But due to what may be described as an individualist bias in cognitive science and psychology (Mercier 2018), these researchers did not draw explicit connections between their findings and the public acts of “giving and asking for reasons”. It is only somewhat recently that argumentation began to receive sustained attention from these researchers. The investigations of Hugo Mercier and colleagues (Mercier & Sperber 2017; Mercier 2018) and of Ulrike Hahn and colleagues (Hahn & Oaksford 2007; Hornikx & Hahn 2012; Collins & Hahn 2018) have been particularly influential. (See also Paglieri, Bonelli, & Felletti 2016, an edited volume containing a representative overview of research on the psychology of argumentation.) Another interesting line of research has been the study of the development of reasoning and argumentative skills in young children (Köymen, Mammen, & Tomasello 2016; Köymen & Tomasello 2020).

Mercier and Sperber defend an interactionist account of reasoning, according to which the primary function of reasoning is for social interactions, where reasons are exchanged and receivers of reasons decide whether they find them convincing—in other words, for argumentation (Mercier & Sperber 2017). They review a wealth of evidence suggesting that reasoning is rather flawed when it comes to drawing conclusions from premises in order to expand one’s knowledge. From this they conclude, on the basis of evolutionary arguments, that the function of reasoning must be a different one, indeed one that responds to features of human sociality and the need to exercise epistemic vigilance when receiving information from others. This account has inaugurated a rich research program which they have been pursuing with colleagues for over a decade now, and which has delivered some interesting results—for example, that we seem to be better at evaluating the quality of arguments proposed by others than at formulating high-quality arguments ourselves (Mercier 2018).

In the context of the Bayesian (see entry on Bayes’ theorem ) approach to reasoning that was first developed by Mike Oaksford and Nick Chater in the 1980s (Oaksford & Chater 2018), Hahn and colleagues have extended the Bayesian framework to the investigation of argumentation. They claim that Bayesian probabilities offer an accurate descriptive model of how people evaluate the strength of arguments (Hahn & Oaksford 2007) as well as a solid perspective to address normative questions pertaining to argument strength (Hahn & Oaksford 2006; Hahn & Hornikx 2016). The Bayesian approach allows for the formulation of probabilistic measures of argument strength, showing that many so-called “fallacies” may nevertheless be good arguments in the sense that they considerably raise the probability of the conclusion. For example, deductively invalid argument schemes (such as affirming the consequent (AC) and denying the antecedent (DA)) can also provide considerable support for a conclusion, depending on the contents in question. The extent to which this is the case depends primarily on the specific informational context, captured by the prior probability distribution, not on the structure of the argument. This means that some instances of, say, AC, may offer support to a conclusion while others may fail to do so (Eva & Hartmann 2018). Thus seen, Bayesian argumentation represents a significantly different approach to argumentation from those inspired by logic (e.g., argument schemes), but they are not necessarily incompatible; they may well be complementary perspectives (see also [Zenker 2013]).

Argumentation is primarily (though not exclusively) a linguistic phenomenon. Accordingly, argumentation is extensively studied in fields dedicated to the study of language, such as rhetoric, linguistics, discourse analysis, communication, and pragmatics, among others (see Eemeren, Garssen, et al. 2014: chs 8 and 9). Researchers in these areas develop general theoretical models of argumentation and investigate concrete instances of argumentation in specific domains on the basis of linguistic corpora, discourse analysis, and other methods used in the language sciences (see the edited volume Oswald, Herman, & Jacquin [2018] for a sample of the different lines of research). Overall, research on argumentation within the language sciences tends to focus primarily on concrete occurrences of arguments in a variety of domains, adopting a largely descriptive rather than normative perspective (though some of these researchers also tackle normative considerations).

Some of these analyses approach arguments and argumentation primarily as text or self-contained speeches, while others emphasize the interpersonal, communicative nature of “face-to-face” argumentation (see Eemeren, Garssen, et al. 2014: section 8.9). One prominent approach in this tradition is due to communication scholars Sally Jackson and Scott Jacobs. They have drawn on speech act theory and conversation analysis to investigate argumentation as a disagreement-relevant expansion of speech acts that, through mutually recognized reasons, allows us to manage disagreements despite the challenges they pose for communication and coordination of activities (Jackson & Jacobs 1980; Jackson 2019). Moreover, they perceive institutionalized practices of argumentation and concrete “argumentation designs”—such as for example randomized controlled trials in medicine—as interventions aimed at improving methods of disagreement management through argumentation.

Another communication scholar, Dale Hample, has further argued for the importance of approaching argumentation as an essentially interpersonal communicative activity (Hample 2006, 2018). This perspective allows for the consideration of a broader range of factors, not only the arguments themselves but also (and primarily) the people involved in those processes: their motivations, psychological processes, and emotions. It also allows for the formulation of questions pertaining to individual as well as cultural differences in argumentative styles (see section 5.3 below).

Another illuminating perspective views argumentative practices as inherently tied to broader socio-cultural contexts (Amossy 2009). The Journal of Argumentation in Context was founded in 2012 precisely to promote a contextual approach to argumentation. Once argumentation is no longer only considered in abstraction from concrete instances taking place in real-life situations, it becomes imperative to recognize that argumentation does not take place in a vacuum; typically, argumentative practices are embedded in other kinds of practices and institutions, against the background of specific socio-cultural, political structures. The method of discourse analysis is particularly suitable for a broader perspective on argumentation, as shown by the work of Ruth Amossy (2002) and Marianne Doury (2009), among others.

Argumentation is crucial in a number of specific organized social practices, in particular in politics, science, law, and education. The relevant argumentative practices are studied in each of the corresponding knowledge domains; indeed, while some general principles may govern argumentative practices across the board, some may be specific to particular applications and domains.

As already mentioned, argumentation is typically viewed as an essential component of political democratic practices, and as such it is of great interest to political scientists and political theorists (Habermas 1992 [1996]; Young 2000; Landemore 2013; Fishkin 2016; see entry on democracy ). (The term typically used in this context is “deliberation” instead of “argumentation”, but these can be viewed as roughly synonymous for our purposes.) General theories of argumentation such as pragma-dialectic and the Toulmin model can be applied to political argumentation with illuminating results (Wodak 2016; Mohammed 2016). More generally, political discourse seems to have a strong argumentative component, in particular if argumentation is understood more broadly as not only pertaining to rational discourse ( logos ) but as also including what rhetoricians refer to as pathos and ethos (Zarefsky 2014; Amossy 2018). But critics of argumentation and deliberation in political contexts also point out the limitations of the classical deliberative model (Sanders 1997; Talisse 2019).

Moreover, scientific communities seem to offer good examples of (largely) well-functioning argumentative practices. These are disciplined systems of collective epistemic activity, with tacit but widely endorsed norms for argumentative engagement for each domain (which does not mean that there are not disagreements on these very norms). The case of mathematics has already been mentioned above: practices of mathematical proof are quite naturally understood as argumentative practices (Dutilh Novaes 2020a). Furthermore, when a scientist presents a new scientific claim, it must be backed by arguments and evidence that her peers are likely to find convincing, as they follow from the application of widely agreed-upon scientific methods (Longino 1990; Weinstein 1990; Rehg 2008; see entry on the social dimensions of scientific knowledge ). Other scientists will in turn critically examine the evidence and arguments provided, and will voice objections or concerns if they find aspects of the theory to be insufficiently convincing. Thus seen, science may be viewed as a “game of giving and asking for reasons” (Zamora Bonilla 2006). Certain features of scientific argumentation seem to ensure its success: scientists see other scientists as prima facie peers, and so (typically at least) place a fair amount of trust in other scientists by default; science is based on the principle of “organized skepticism” (a term introduced by the pioneer sociologist of science Robert Merton [Merton, 1942]), which means that asking for further reasons should not be perceived as a personal attack. These are arguably aspects that distinguish argumentation in science from argumentation in other domains in virtue of these institutional factors (Mercier & Heintz 2014). But ultimately, scientists are part of society as a whole, and thus the question of how scientific and political argumentation intersect becomes particularly relevant (Kitcher 2001).

Another area where argumentation is essential is the law, which also corresponds to disciplined systems of collective activity with rules and principles for what counts as acceptable arguments and evidence. legal reasoning ).--> In litigation (in particular in adversarial justice systems), there are typically two sides disagreeing on what is lawful or just, and the basic idea is that each side will present its strongest arguments; it is the comparison between the two sets of arguments that should lead to the best judgment (Walton 2002). Legal reasoning and argumentation have been extensively studied within jurisprudence for decades, in particular since Ronald Dworkin’s (1977) and Neil MacCormick’s (1978) responses to HLA Hart’s highly influential The Concept of Law (1961). A number of other views and approaches have been developed, in particular from the perspectives of natural law theory, legal positivism, common law, and rhetoric (see Feteris 2017 for an overview). Overall, legal argumentation is characterized by extensive uses of analogies (Lamond 2014), abduction (Askeland 2020), and defeasible/non-monotonic reasoning (Bex & Verheij 2013). An interesting question is whether argumentation in law is fundamentally different from argumentation in other domains, or whether it follows the same overall canons and norms but applied to legal topics (Raz 2001).

Finally, the development of argumentative skills is arguably a fundamental aspect of (formal) education (Muller Mirza & Perret-Clermont 2009). Ideally, when presented with arguments, a learner should not simply accept what is being said at face value, but should instead reflect on the reasons offered and come to her own conclusions. Argumentation thus fosters independent, critical thinking, which is viewed as an important goal for education (Siegel 1995; see entry on critical thinking ). A number of education theorists and developmental psychologists have empirically investigated the effects of emphasizing argumentative skills in educational settings, with encouraging results (Kuhn & Crowell 2011). There has been in particular much emphasis on argumentation specifically in science education, based on the assumption that argumentation is a key component of scientific practice (as noted above); the thought is that this feature of scientific practice should be reflected in science education (Driver, Newton, & Osborne 2000; Erduran & Jiménez-Aleixandre 2007).

5. Further Topics

Argumentation is a multi-faceted phenomenon, and the literature on arguments and argumentation is massive and varied. This entry can only scratch the surface of the richness of this material, and many interesting, relevant topics must be left out for reasons of space. In this final section, a selection of topics that are likely to attract considerable interest in future research are discussed.

In recent years, the concept of epistemic injustice has received much attention among philosophers (Fricker 2007; McKinnon 2016). Epistemic injustice occurs when a person is unfairly treated qua knower on the basis of prejudices pertaining to social categories such as gender, race, class, ability etc. (see entry on feminist epistemology and philosophy of science ). One of the main categories of epistemic injustice discussed in the literature pertains to testimony and is known as testimonial injustice : this occurs when a testifier is not given a degree of credibility commensurate to their actual expertise on the relevant topic, as a result of prejudice. (Whether credibility excess is also a form of testimonial injustice is a moot point in the literature [Medina 2011].)

Since argumentation can be viewed as an important mechanism for sharing knowledge and information, i.e., as having significant epistemic import (Goldman 2004), the question arises whether there might be instances of epistemic injustice pertaining specifically to argumentation, which may be described as argumentative injustice , and which would be notably different from other recognized forms of epistemic injustice such as testimonial injustice. Bondy (Bondy 2010) presented a first articulation of the notion of argumentative injustice, modeled after Fricker’s notion of epistemic injustice and relying on a broadly epistemological conception of argumentation. However, Bondy’s analysis does not take into account some of the structural elements that have become central to the analysis of epistemic injustice since Fricker’s influential work, so it seems further discussion of epistemic injustice in argumentation is still needed. For example, in situations of disagreement, epistemic injustice can give rise to further obstacles to rational argumentation, leading to deep disagreement (Lagewaard 2021).

Moreover, as often noted by critics of adversarial approaches, argumentation can also be used as an instrument of domination and oppression used to overpower and denigrate an interlocutor (Nozick 1981), especially an interlocutor of “lower” status in the context in question (Moulton 1983; see entry on feminist approaches to argumentation ). From this perspective, it is clear that argumentation may also be used to reinforce and exacerbate injustice, inequalities and power differentials (Goodwin 2007). Given this possibility, and in response to the perennial risk of excessive aggressiveness in argumentative situations, a normative account of how argumentation ought to be conducted so as to avoid these problematic outcomes seem to be required.

One such approach is virtue argumentation theory . Drawing on virtue ethics and virtue epistemology (see entries on virtue ethics and virtue epistemology ), virtue argumentation theory seeks to theorize how to argue well in terms of the dispositions and character of arguers rather than, for example, in terms of properties of arguments considered in abstraction from arguers (Aberdein & Cohen 2016). Some of the argumentative virtues identified in the literature are: willingness to listen to others (Cohen 2019), willingness to take a novel viewpoint seriously (Kwong 2016), humility (Kidd 2016), and open-mindedness (Tanesini 2020).

By the same token, defective argumentation is conceptualized not (only) in terms of structural properties of arguments (e.g., fallacious argument patterns), but in terms of the vices displayed by arguers such as arrogance and narrow-mindedness, among others (Aberdein 2016). Virtue argumentation theory now constitutes a vibrant research program, as attested by a special issue of Topoi dedicated to the topic (see [Aberdein & Cohen 2016] for its Introduction). It allows for a reconceptualization of classical themes within argumentation theory while also promising to provide concrete recommendations on how to argue better. Whether it can fully counter the risk of epistemic injustice and oppressive uses of argumentation is however debatable, at least as long as broader structural factors related to power dynamics are not sufficiently taken into account (Kukla 2014).

On some idealized construals, argumentation is conceived as a purely rational, emotionless endeavor. But the strong connection between argumentative activities and emotional responses has also long been recognized (in particular in rhetorical analyses of argumentation), and more recently has become the object of extensive research (Walton 1992; Gilbert 2004; Hample 2006: ch. 5). Importantly, the recognition of a role for emotions in argumentation does not entail a complete rejection of the “rationality” of argumentation; rather, it is based on the rejection of a strict dichotomy between reason and emotion (see entry on emotion ), and on a more encompassing conception of argumentation as a multi-layered human activity.

Rather than dispassionate exchanges of reasons, instances of argumentation typically start against the background of existing emotional relations, and give rise to further affective responses—often, though not necessarily, negative responses of aggression and hostility. Indeed, it has been noted that, by itself, argumentation can give rise to conflict and friction where there was none to be found prior to the argumentative engagement (Aikin 2011). This occurs in particular because critical engagement and requests for reasons are at odds with default norms of credulity in most mundane dialogical interactions, thus creating a perception of antagonism. But argumentation may also give rise to positive affective responses if the focus is on coalescence and cooperation rather than on hostility (Gilbert 1997).

The descriptive claim that instances of argumentation are typically emotionally charged is not particularly controversial, though it deserves to be further investigated; the details of affective responses during instances of argumentation and how to deal with them are non-trivial (Krabbe & van Laar 2015). What is potentially more controversial is the normative claim that instances of argumentation may or should be emotionally charged, i.e., that emotions may or ought to be involved in argumentative processes, even if it may be necessary to regulate them in such situations rather than giving them free rein (González, Gómez, & Lemos 2019). The significance of emotions for persuasion has been recognized for millennia (see entry on Aristotle’s rhetoric ), but more recently it has become clear that emotions also have a fundamental role to play for choices of what to focus on and what to care about (Sinhababu 2017). This general point seems to apply to instances of argumentation as well. For example, Howes and Hundleby (Howes & Hundleby 2018) argue that, contrary to what is often thought, anger can in fact make a positive contribution to argumentative encounters. Indeed, anger may have an important epistemological role in such encounters by drawing attention to relevant premises and information that may otherwise go unnoticed. (They recognize that anger may also derail argumentation when the encounter becomes a full-on confrontation.)

In sum, the study of the role of emotions for argumentation, both descriptively and normatively speaking, has attracted the interest of a number of scholars, traditionally in connection with rhetoric and more recently also from the perspective of argumentation as interpersonal communication (Hample 2006). And yet, much work remains to be done on the significance of emotions for argumentation, in particular given that the view that argumentation should be a purely rational, dispassionate endeavor remains widely (even if tacitly) endorsed.

Once we adopt the perspective of argumentation as a communicative practice, the question of the influence of cultural factors on argumentative practices naturally arises. Is there significant variability in how people engage in argumentation depending on their sociocultural backgrounds? Or is argumentation largely the same phenomenon across different cultures? Actually, we may even ask ourselves whether argumentation in fact occurs in all human cultures, or whether it is the product of specific, contingent background conditions, thus not being a human universal. For comparison: it had long been assumed that practices of counting were present in all human cultures, even if with different degrees of complexity. But in recent decades it has been shown that some cultures do not engage systematically in practices of counting and basic arithmetic at all, such as the Pirahã in the Amazon (Gordon 2004; see entry on culture and cognitive science ). By analogy, it seems that the purported universality of argumentative practices should not be taken for granted, but rather be treated as a legitimate empirical question. (Incidentally, there is some anecdotal evidence that the Pirahã themselves engage in argumentative exchanges [Everett 2008], but to date their argumentative skills have not been investigated systematically, as is the case with their numerical skills.)

Of course, how widespread argumentative practices will be also depends on how the concept of “argumentative practices” is defined and operationalized in the first place. If it is narrowly defined as corresponding to regimented practices of reason-giving requiring clear markers and explicit criteria for what counts as premises, conclusions and relations of support between them, then argumentation may well be restricted to cultures and subcultures where such practices have been explicitly codified. By contrast, if argumentation is defined more loosely, then a wider range of communicative practices will be considered as instances of argumentation, and thus presumably more cultures will be found to engage in (what is thus viewed as) argumentation. This means that the spread of argumentative practices across cultures is not only an empirical question; it also requires significant conceptual input to be addressed.

But if (as appears to be the case) argumentation is not a strictly WEIRD phenomenon, restricted to Western, Educated, Industrialized, Rich, and Democratic societies (Henrich, Heine, & Norenzayan 2010), then the issue of cross-cultural variability in argumentative practices gives rise to a host of research questions, again both at the descriptive and at the normative level. Indeed, even if at the descriptive level considerable variability in argumentative practices is identified, the normative question of whether there should be universally valid canons for argumentation, or instead specific norms for specific contexts, remains pressing. At the descriptive level, a number of researchers have investigated argumentative practices in different WEIRD as well as non-WEIRD cultures, also addressing questions of cultural variability (Hornikx & Hoeken 2007; Hornikx & de Best 2011).

A foundational work in this context is Edwin Hutchins’ 1980 book Culture and Inference , a study of the Trobriand Islanders’ system of land tenure in Papua New Guinea (Hutchins 1980). While presented as a study of inference and reasoning among the Trobriand Islanders, what Hutchins in fact investigated were instances of legal argumentation in land courts by means of ethnographic observation and interviews with litigants. This led to the formulation of a set of twelve basic propositions codifying knowledge about land tenure, as well as transfer formulas governing how this knowledge can be applied to new disputes. Hutchins’ analysis showed that the Trobriand Islanders had a sophisticated argumentation system to resolve issues pertaining to land tenure, in many senses resembling argumentation and reasoning in so-called WEIRD societies in that it seemed to recognize as valid simple logical structures such as modus ponens and modus tollens .

More recently, Hugo Mercier and colleagues have been conducting studies in countries such as Japan (Mercier, Deguchi, Van der Henst, & Yama 2016) and Guatemala (Castelain, Girotto, Jamet, & Mercier 2016). While recognizing the significance and interest of cultural differences (Mercier 2013), Mercier maintains that argumentation is a human universal, as argumentative capacities and tendencies are a result of natural selection, genetically encoded in human cognition (Mercier 2011; Mercier & Sperber 2017). He takes the results of the cross-cultural studies conducted so far as confirming the universality of argumentation, even considering cultural differences (Mercier 2018).

Another scholar who has been carrying out an extensive research program on cultural differences in argumentation is communication theorist Dale Hample. With different sets of colleagues, he has conducted studies by means of surveys where participants (typically, university undergraduates) self-report on their argumentative practices in countries such as China, Japan, Turkey, Chile, the Netherlands, Portugal, the United States (among others; Hample 2018: ch. 7). His results overall show a number of similarities, which may be partially explained by the specific demographic (university students) from which participants are usually recruited. But interesting differences have also been identified, for example different levels of willingness to engage in argumentative encounters.

In a recent book (Tindale 2021), philosopher Chris Tindale adopts an anthropological perspective to investigate how argumentative practices emerge from the experiences of peoples with diverse backgrounds. He emphasizes the argumentative roles of place, orality, myth, narrative, and audience, also assessing the impacts of colonialism on the study of argumentation. Tindale reviews a wealth of anthropological and ethnographic studies on argumentative practices in different cultures, thus providing what is to date perhaps the most comprehensive study on argumentation from an anthropological perspective.

On the whole, the study of differences and commonalities in argumentative practices across cultures is an established line of research on argumentation, but arguably much work remains to be done to investigate these complex phenomena more thoroughly.

So far we have not yet considered the question of the different media through which argumentation can take place. Naturally, argumentation can unfold orally in face-to-face encounters—discussions in parliament, political debates, in a court of law—as well as in writing—in scientific articles, on the Internet, in newspaper editorials. Moreover, it can happen synchronically, with real-time exchanges of reasons, or asynchronically. While it is reasonable to expect that there will be some commonalities across these different media and environments, it is also plausible that specific features of different environments may significantly influence how argumentation is conducted: different environments present different kinds of affordances for arguers (Halpern & Gibbs 2013; Weger & Aakhus 2003; see entry on embodied cognition for the concept of affordance). Indeed, if the Internet represents a fundamentally novel cognitive ecology (Smart, Heersmink, & Clowes 2017), then it will likely give rise to different forms of argumentative engagement (Lewiński 2010). Whether these new forms will represent progress (according to some suitable metric) is however a moot point.

In the early days of the Internet in the 1990s, there was much hope that online spaces would finally realize the Habermasian ideal of a public sphere for political deliberation (Hindman 2009). The Internet was supposed to act as the great equalizer in the worldwide marketplace of ideas, finally attaining the Millian ideal of free exchange of ideas (Mill 1859). Online, everyone’s voice would have an equal chance of being heard, everyone could contribute to the conversation, and everyone could simultaneously be a journalist, news consumer, engaged citizen, advocate, and activist.

A few decades later, these hopes have not really materialized. It is probably true that most people now argue more —in social media, blogs, chat rooms, discussion boards etc.—but it is much less obvious that they argue better . Indeed, rather than enhancing democratic ideals, some have gone as far as claiming that instead, the Internet is “killing democracy” (Bartlett 2018). There is very little oversight when it comes to the spreading of propaganda and disinformation online (Benkler, Faris, & Roberts 2018), which means that citizens are often being fed faulty information and arguments. Moreover, it seems that online environments may lead to increased polarization when polemic topics are being discussed (Yardi & Boyd 2010), and to “intellectual arrogance” (Lynch 2019). Some have argued that online discussions lead to more overly emotional engagement when compared to other forms of debate (Kramer, Guillory, & Hancock 2014). But not everyone is convinced that the Internet has only made things worse when it comes to argumentation, or in any case that it cannot be suitably redesigned so as to foster rather than destroy democratic ideals and deliberation (Sunstein 2017).

Be that as it may, the Internet is here to stay, and online argumentation is a pervasive phenomenon that argumentation theorists have been studying and will continue to study for years to come. In fact, if anything, online argumentation is now more often investigated empirically than other forms of argumentation, among other reasons thanks to the development of argument mining techniques (see section 4.2 above) which greatly facilitate the study of large corpora of textual material such as those produced by online discussions. Beyond the very numerous specific case studies available in the literature, there have been also attempts to reflect on the phenomenon of online argumentation in general, for example in journal special issues dedicated to argumentation in digital media such as in Argumentation and Advocacy (Volume 47(2), 2010) and Philosophy & Technology (Volume 30(2), 2017). However, a systematic analysis of online argumentation and how it differs from other forms of argumentation remains to be produced.

Argument and argumentation are multifaceted phenomena that have attracted the interest of philosophers as well as scholars in other fields for millennia, and continue to be studied extensively in various domains. This entry presents an overview of the main strands in these discussions, while acknowledging the impossibility of fully doing justice to the enormous literature on the topic. But the literature references below should at least provide a useful starting point for the interested reader.

• Aberdein, Andrew, 2016, “The Vices of Argument”, Topoi , 35(2): 413–422. doi:10.1007/s11245-015-9346-z
• Aberdein, Andrew and Daniel H. Cohen, 2016, “Introduction: Virtues and Arguments”, Topoi , 35(2): 339–343. doi:10.1007/s11245-016-9366-3
• Aberdein, Andrew and Ian J Dove (eds.), 2013, The Argument of Mathematics , Dordrecht: Springer Netherlands. doi:10.1007/978-94-007-6534-4
• Aikin, Scott, 2011, “A Defense of War and Sport Metaphors in Argument”, Philosophy & Rhetoric , 44(3): 250–272.
• Amossy, Ruth, 2002, “How to Do Things with Doxa: Toward an Analysis of Argumentation in Discourse”, Poetics Today , 23(3): 465–487. doi:10.1215/03335372-23-3-465
• –––, 2009, “Argumentation in Discourse: A Socio-Discursive Approach to Arguments”, Informal Logic , 29(3): 252–267. doi:10.22329/il.v29i3.2843
• –––, 2018, “Understanding Political Issues through Argumentation Analysis”, in The Routledge Handbook of Language and Politics , Ruth Wodak and Bernard Forchtner (eds.), New York: Routledge, pp. 135–149.
• Askeland, Bjarte, 2020, “The Potential of Abductive Legal Reasoning”, Ratio Juris , 33(1): 66–81. doi:10.1111/raju.12268
• Atkinson, Katie, Federico Cerutti, Peter McBurney, Simon Parsons, and Iyad Rahwan (eds), 2016, Special Issue on Argumentation in Multi-Agent Systems , of Argument & Computation , 7(2–3).
• Bailin, Sharon and Mark Battersby, 2016, “DAMed If You Do; DAMed If You Don’t: Cohen’s ‘Missed Opportunities’”, in Proceedings of the Ontario Society for the Study of Argumentation Conference , Vol. 11. [ Bailin and Battersby 2016 available online ]
• Ball, Linden J and Valerie A. Thompson (eds.), 2018, International Handbook of Thinking and Reasoning , London: Routledge. doi:10.4324/9781315725697
• Bartlett, Jamie, 2018, The People vs Tech: How the Internet is Killing Democracy (and How We Can Save It) , London: Ebury Press.
• Beall, Jc, 2009, Spandrels of Truth , Oxford: Oxford University Press. doi:10.1093/acprof:oso/9780199268733.001.0001
• Benkler, Yochai, Robert Faris, and Hal Roberts, 2018, Network Propaganda: Manipulation, Disinformation, and Radicalization in American Politics , New York: Oxford University Press. doi:10.1093/oso/9780190923624.001.0001
• Bermejo Luque, Lilian, 2011, Giving Reasons: A Linguistic-Pragmatic Approach to Argumentation Theory (Argumentation Library 20), Dordrecht: Springer Netherlands. doi:10.1007/978-94-007-1761-9
• –––, 2020, “What Is Wrong with Deductivism?”, Informal Logic , 40(3): 295–316. doi:10.22329/il.v40i30.6214
• Betz, Gregor, 2013, Debate Dynamics: How Controversy Improves Our Beliefs , Dordrecht: Springer Netherlands. doi:10.1007/978-94-007-4599-5
• Bex, Floris, Henry Prakken, Chris Reed, and Douglas Walton, 2003, “Towards a Formal Account of Reasoning about Evidence: Argumentation Schemes and Generalisations”, Artificial Intelligence and Law , 11(2/3): 125–165. doi:10.1023/B:ARTI.0000046007.11806.9a
• Bex, Floris and Bart Verheij, 2013, “Legal Stories and the Process of Proof”, Artificial Intelligence and Law , 21(3): 253–278. doi:10.1007/s10506-012-9137-4
• Biro, John and Harvey Siegel, 2006, “In Defense of the Objective Epistemic Approach to Argumentation”, Informal Logic , 26(1): 91–101. doi:10.22329/il.v26i1.432
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abduction | analogy: medieval theories of | analogy and analogical reasoning | Aristotle | Aristotle, General Topics: logic | Aristotle, General Topics: rhetoric | Bacon, Francis | Bayes’ Theorem | bias, implicit | Chinese Philosophy: logic and language in Early Chinese Philosophy | Chinese Philosophy: Mohism | Chinese Philosophy: Mohist Canons | Chinese room argument | cognition: embodied | critical thinking | Curry’s paradox | democracy | emotion | epistemology: virtue | ethics: virtue | fallacies | feminist philosophy, interventions: epistemology and philosophy of science | feminist philosophy, interventions: political philosophy | feminist philosophy, topics: perspectives on argumentation | Habermas, Jürgen | Hume, David | induction: problem of | legal reasoning: precedent and analogy in | liar paradox | logic: inductive | logic: informal | logic: non-monotonic | logic: paraconsistent | logic: relevance | logical consequence | Peirce, Charles Sanders | reasoning: defeasible | scientific knowledge: social dimensions of | Spinoza, Baruch | Stebbing, Susan | thought experiments

Acknowledgments

Thanks to Merel Talbi, Elias Anttila, César dos Santos, Hein Duijf, Silvia Ivani, Caglar Dede, Colin Rittberg, Marcin Lewiński, Andrew Aberdein, Malcolm Keating, Maksymillian Del Mar, and an anonymous referee for suggestions and/or comments on earlier drafts. This research was supported by H2020 European Research Council [771074-SEA].

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• What Is Critical Thinking? | Definition & Examples

What Is Critical Thinking? | Definition & Examples

Published on May 30, 2022 by Eoghan Ryan . Revised on May 31, 2023.

Critical thinking is the ability to effectively analyze information and form a judgment .

To think critically, you must be aware of your own biases and assumptions when encountering information, and apply consistent standards when evaluating sources .

Critical thinking skills help you to:

• Identify credible sources
• Evaluate and respond to arguments
• Assess alternative viewpoints
• Test hypotheses against relevant criteria

Table of contents

Why is critical thinking important, critical thinking examples, how to think critically, other interesting articles, frequently asked questions about critical thinking.

Critical thinking is important for making judgments about sources of information and forming your own arguments. It emphasizes a rational, objective, and self-aware approach that can help you to identify credible sources and strengthen your conclusions.

Critical thinking is important in all disciplines and throughout all stages of the research process . The types of evidence used in the sciences and in the humanities may differ, but critical thinking skills are relevant to both.

In academic writing , critical thinking can help you to determine whether a source:

• Is free from research bias
• Provides evidence to support its research findings
• Considers alternative viewpoints

Outside of academia, critical thinking goes hand in hand with information literacy to help you form opinions rationally and engage independently and critically with popular media.

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Critical thinking can help you to identify reliable sources of information that you can cite in your research paper . It can also guide your own research methods and inform your own arguments.

Outside of academia, critical thinking can help you to be aware of both your own and others’ biases and assumptions.

Academic examples

However, when you compare the findings of the study with other current research, you determine that the results seem improbable. You analyze the paper again, consulting the sources it cites.

You notice that the research was funded by the pharmaceutical company that created the treatment. Because of this, you view its results skeptically and determine that more independent research is necessary to confirm or refute them. Example: Poor critical thinking in an academic context You’re researching a paper on the impact wireless technology has had on developing countries that previously did not have large-scale communications infrastructure. You read an article that seems to confirm your hypothesis: the impact is mainly positive. Rather than evaluating the research methodology, you accept the findings uncritically.

Nonacademic examples

However, you decide to compare this review article with consumer reviews on a different site. You find that these reviews are not as positive. Some customers have had problems installing the alarm, and some have noted that it activates for no apparent reason.

You revisit the original review article. You notice that the words “sponsored content” appear in small print under the article title. Based on this, you conclude that the review is advertising and is therefore not an unbiased source. Example: Poor critical thinking in a nonacademic context You support a candidate in an upcoming election. You visit an online news site affiliated with their political party and read an article that criticizes their opponent. The article claims that the opponent is inexperienced in politics. You accept this without evidence, because it fits your preconceptions about the opponent.

There is no single way to think critically. How you engage with information will depend on the type of source you’re using and the information you need.

However, you can engage with sources in a systematic and critical way by asking certain questions when you encounter information. Like the CRAAP test , these questions focus on the currency , relevance , authority , accuracy , and purpose of a source of information.

When encountering information, ask:

• Who is the author? Are they an expert in their field?
• What do they say? Is their argument clear? Can you summarize it?
• When did they say this? Is the source current?
• Where is the information published? Is it an academic article? Is it peer-reviewed ?
• Why did the author publish it? What is their motivation?
• How do they make their argument? Is it backed up by evidence? Does it rely on opinion, speculation, or appeals to emotion ? Do they address alternative arguments?

Critical thinking also involves being aware of your own biases, not only those of others. When you make an argument or draw your own conclusions, you can ask similar questions about your own writing:

• Am I only considering evidence that supports my preconceptions?
• Is my argument expressed clearly and backed up with credible sources?
• Would I be convinced by this argument coming from someone else?

If you want to know more about ChatGPT, AI tools , citation , and plagiarism , make sure to check out some of our other articles with explanations and examples.

• ChatGPT vs human editor
• ChatGPT citations
• Is ChatGPT trustworthy?
• Using ChatGPT for your studies
• What is ChatGPT?
• Chicago style
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Critical thinking refers to the ability to evaluate information and to be aware of biases or assumptions, including your own.

Like information literacy , it involves evaluating arguments, identifying and solving problems in an objective and systematic way, and clearly communicating your ideas.

Critical thinking skills include the ability to:

You can assess information and arguments critically by asking certain questions about the source. You can use the CRAAP test , focusing on the currency , relevance , authority , accuracy , and purpose of a source of information.

Ask questions such as:

• Who is the author? Are they an expert?
• How do they make their argument? Is it backed up by evidence?

A credible source should pass the CRAAP test  and follow these guidelines:

• The information should be up to date and current.
• The author and publication should be a trusted authority on the subject you are researching.
• The sources the author cited should be easy to find, clear, and unbiased.
• For a web source, the URL and layout should signify that it is trustworthy.

Information literacy refers to a broad range of skills, including the ability to find, evaluate, and use sources of information effectively.

Being information literate means that you:

• Know how to find credible sources
• Use relevant sources to inform your research
• Understand what constitutes plagiarism
• Know how to cite your sources correctly

Confirmation bias is the tendency to search, interpret, and recall information in a way that aligns with our pre-existing values, opinions, or beliefs. It refers to the ability to recollect information best when it amplifies what we already believe. Relatedly, we tend to forget information that contradicts our opinions.

Although selective recall is a component of confirmation bias, it should not be confused with recall bias.

On the other hand, recall bias refers to the differences in the ability between study participants to recall past events when self-reporting is used. This difference in accuracy or completeness of recollection is not related to beliefs or opinions. Rather, recall bias relates to other factors, such as the length of the recall period, age, and the characteristics of the disease under investigation.

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Critical thinking definition

Critical thinking, as described by Oxford Languages, is the objective analysis and evaluation of an issue in order to form a judgement.

Active and skillful approach, evaluation, assessment, synthesis, and/or evaluation of information obtained from, or made by, observation, knowledge, reflection, acumen or conversation, as a guide to belief and action, requires the critical thinking process, which is why it's often used in education and academics.

Some even may view it as a backbone of modern thought.

However, it's a skill, and skills must be trained and encouraged to be used at its full potential.

People turn up to various approaches in improving their critical thinking, like:

• Developing technical and problem-solving skills
• Engaging in more active listening
• Actively questioning their assumptions and beliefs
• Seeking out more diversity of thought
• Opening up their curiosity in an intellectual way etc.

Is critical thinking useful in writing?

Critical thinking can help in planning your paper and making it more concise, but it's not obvious at first. We carefully pinpointed some the questions you should ask yourself when boosting critical thinking in writing:

• What information should be included?
• Which information resources should the author look to?
• What degree of technical knowledge should the report assume its audience has?
• What is the most effective way to show information?
• How should the report be organized?
• How should it be designed?
• What tone and level of language difficulty should the document have?

Usage of critical thinking comes down not only to the outline of your paper, it also begs the question: How can we use critical thinking solving problems in our writing's topic?

Let's say, you have a Powerpoint on how critical thinking can reduce poverty in the United States. You'll primarily have to define critical thinking for the viewers, as well as use a lot of critical thinking questions and synonyms to get them to be familiar with your methods and start the thinking process behind it.

Are there any services that can help me use more critical thinking?

We understand that it's difficult to learn how to use critical thinking more effectively in just one article, but our service is here to help.

We are a team specializing in writing essays and other assignments for college students and all other types of customers who need a helping hand in its making. We cover a great range of topics, offer perfect quality work, always deliver on time and aim to leave our customers completely satisfied with what they ordered.

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1: Introduction to Critical Thinking, Reasoning, and Logic

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What is thinking? It may seem strange to begin a logic textbook with this question. ‘Thinking’ is perhaps the most intimate and personal thing that people do. Yet the more you ‘think’ about thinking, the more mysterious it can appear. It is the sort of thing that one intuitively or naturally understands, and yet cannot describe to others without great difficulty. Many people believe that logic is very abstract, dispassionate, complicated, and even cold. But in fact the study of logic is nothing more intimidating or obscure than this: the study of good thinking.

• 1.1: Prelude to Chapter
• 1.2: Introduction and Thought Experiments- The Trolley Problem
• 1.3: Truth and Its Role in Argumentation - Certainty, Probability, and Monty Hall Only certain sorts of sentences can be used in arguments. We call these sentences propositions, statements or claims.
• 1.4: Distinction of Proof from Verification; Our Biases and the Forer Effect
• 1.5: The Scientific Method The procedure that scientists use is also a standard form of argument. Its conclusions only give you the likelihood or the probability that something is true (if your theory or hypothesis is confirmed), and not the certainty that it’s true. But when it is done correctly, the conclusions it reaches are very well-grounded in experimental evidence.
• 1.6: Diagramming Thoughts and Arguments - Analyzing News Media
• 1.7: Creating a Philosophical Outline

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Defining Critical Thinking