bad 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 ) . ↩︎

2 Logic and the Study of Arguments

If we want to study how we ought to reason (normative) we should start by looking at the primary way that we do reason (descriptive): through the use of arguments. In order to develop a theory of good reasoning, we will start with an account of what an argument is and then proceed to talk about what constitutes a “good” argument.

I. Arguments

• Arguments are a set of statements (premises and conclusion).
• The premises provide evidence, reasons, and grounds for the conclusion.
• The conclusion is what is being argued for.
• An argument attempts to draw some logical connection between the premises and the conclusion.
• And in doing so, the argument expresses an inference: a process of reasoning from the truth of the premises to the truth of the conclusion.

Example : The world will end on August 6, 2045. I know this because my dad told me so and my dad is smart.

In this instance, the conclusion is the first sentence (“The world will end…”); the premises (however dubious) are revealed in the second sentence (“I know this because…”).

II. Statements

Conclusions and premises are articulated in the form of statements . Statements are sentences that can be determined to possess or lack truth. Some examples of true-or-false statements can be found below. (Notice that while some statements are categorically true or false, others may or may not be true depending on when they are made or who is making them.)

Examples of sentences that are statements:

• It is below 40°F outside.
• Oklahoma is north of Texas.
• The Denver Broncos will make it to the Super Bowl.
• Russell Westbrook is the best point guard in the league.
• I like broccoli.
• I shouldn’t eat French fries.
• Time travel is possible.
• If time travel is possible, then you can be your own father or mother.

However, there are many sentences that cannot so easily be determined to be true or false. For this reason, these sentences identified below are not considered statements.

• Questions: “What time is it?”
• Commands: “Do your homework.”
• Requests: “Please clean the kitchen.”
• Proposals: “Let’s go to the museum tomorrow.”

Question: Why are arguments only made up of statements?

First, we only believe statements . It doesn’t make sense to talk about believing questions, commands, requests or proposals. Contrast sentences on the left that are not statements with sentences on the right that are statements:

It would be non-sensical to say that we believe the non-statements (e.g. “I believe what time is it?”). But it makes perfect sense to say that we believe the statements (e.g. “I believe the time is 11 a.m.”). If conclusions are the statements being argued for, then they are also ideas we are being persuaded to believe. Therefore, only statements can be conclusions.

Second, only statements can provide reasons to believe.

• Q: Why should I believe that it is 11:00 a.m.? A: Because the clock says it is 11a.m.
• Q: Why should I believe that we are going to the museum tomorrow? A: Because today we are making plans to go.

Sentences that cannot be true or false cannot provide reasons to believe. So, if premises are meant to provide reasons to believe, then only statements can be premises.

III. Representing Arguments

As we concern ourselves with arguments, we will want to represent our arguments in some way, indicating which statements are the premises and which statement is the conclusion. We shall represent arguments in two ways. For both ways, we will number the premises.

In order to identify the conclusion, we will either label the conclusion with a (c) or (conclusion). Or we will mark the conclusion with the ∴ symbol

Example Argument:

There will be a war in the next year. I know this because there has been a massive buildup in weapons. And every time there is a massive buildup in weapons, there is a war. My guru said the world will end on August 6, 2045.

• There has been a massive buildup in weapons.
• Every time there has been a massive buildup in weapons, there is a war.

(c) There will be a war in the next year.

∴ There will be a war in the next year.

Of course, arguments do not come labeled as such. And so we must be able to look at a passage and identify whether the passage contains an argument and if it does, we should also be identify which statements are the premises and which statement is the conclusion. This is harder than you might think!

There is no argument here. There is no statement being argued for. There are no statements being used as reasons to believe. This is simply a report of information.

The following are also not arguments:

Advice: Be good to your friends; your friends will be good to you.

Warnings: No lifeguard on duty. Be careful.

Associated claims: Fear leads to anger. Anger leads to the dark side.

When you have an argument, the passage will express some process of reasoning. There will be statements presented that serve to help the speaker building a case for the conclusion.

IV. How to L ook for A rguments [1]

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 afterward. 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.” In the first instance (“since noon”) “since” means “from.” In the second instance, “since” means “because.”

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

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

Here are some examples of passages that do not contain arguments.

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

2. 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.]

3. 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?

• Cutting the interest rate will have no effect on the stock market this time around, as people have been expecting a rate cut all along. This factor has already been reflected in the market.
• So it is raining heavily and this building might collapse. But I don’t really care.
• Virgin would then dominate the rail system. Is that something the government should worry about? Not necessarily. The industry is regulated, and one powerful company might at least offer a more coherent schedule of services than the present arrangement has produced. The reason the industry was broken up into more than 100 companies at privatization was not operational, but political: the Conservative government thought it would thus be harder to renationalize (The Economist 12/16/2000).
• Bill will pay the ransom. After all, he loves his wife and children and would do everything to save them.
• All of Russia’s problems of human rights and democracy come back to three things: the legislature, the executive and the judiciary. None works as well as it should. Parliament passes laws in a hurry, and has neither the ability nor the will to call high officials to account. State officials abuse human rights (either on their own, or on orders from on high) and work with remarkable slowness and disorganization. The courts almost completely fail in their role as the ultimate safeguard of freedom and order (The Economist 11/25/2000).
• Most mornings, Park Chang Woo arrives at a train station in central Seoul, South Korea’s capital. But he is not commuter. He is unemployed and goes there to kill time. Around him, dozens of jobless people pass their days drinking soju, a local version of vodka. For the moment, middle-aged Mr. Park would rather read a newspaper. He used to be a bricklayer for a small construction company in Pusan, a southern port city. But three years ago the country’s financial crisis cost him that job, so he came to Seoul, leaving his wife and two children behind. Still looking for work, he has little hope of going home any time soon (The Economist 11/25/2000).
• For a long time, astronomers suspected that Europa, one of Jupiter’s many moons, might harbour a watery ocean beneath its ice-covered surface. They were right. Now the technique used earlier this year to demonstrate the existence of the Europan ocean has been employed to detect an ocean on another Jovian satellite, Ganymede, according to work announced at the recent American Geo-physical Union meeting in San Francisco (The Economist 12/16/2000).
• There are no hard numbers, but the evidence from Asia’s expatriate community is unequivocal. Three years after its handover from Britain to China, Hong Kong is unlearning English. The city’s gweilos (Cantonese for “ghost men”) must go to ever greater lengths to catch the oldest taxi driver available to maximize their chances of comprehension. Hotel managers are complaining that they can no longer find enough English-speakers to act as receptionists. Departing tourists, polled at the airport, voice growing frustration at not being understood (The Economist 1/20/2001).

V. Evaluating Arguments

Q: What does it mean for an argument to be good? What are the different ways in which arguments can be good? Good arguments:

• Are persuasive.
• Have premises that provide good evidence for the conclusion.
• Contain premises that are true.
• Reach a true conclusion.
• Provide the audience good reasons for accepting the conclusion.

The focus of logic is primarily about one type of goodness: The logical relationship between premises and conclusion.

An argument is good in this sense if the premises provide good evidence for the conclusion. But what does it mean for premises to provide good evidence? We need some new concepts to capture this idea of premises providing good logical support. In order to do so, we will first need to distinguish between two types of argument.

VI. Two Types of Arguments

The two main types of arguments are called deductive and inductive arguments. We differentiate them in terms of the type of support that the premises are meant to provide for the conclusion.

Deductive Arguments are arguments in which the premises are meant to provide conclusive logical support for the conclusion.

1. All humans are mortal

2. Socrates is a human.

∴ Therefore, Socrates is mortal.

1. No student in this class will fail.

2. Mary is a student in this class.

∴ Therefore, Mary will not fail.

1. A intersects lines B and C.

2. Lines A and B form a 90-degree angle

3. Lines A and C form a 90-degree angle.

∴ B and C are parallel lines.

Inductive arguments are, by their very nature, risky arguments.

Arguments in which premises provide probable support for the conclusion.

Statistical Examples:

1. Ten percent of all customers in this restaurant order soda.

2. John is a customer.

∴ John will not order Soda..

1. Some students work on campus.

2. Bill is a student.

∴ Bill works on campus.

1. Vegas has the Carolina Panthers as a six-point favorite for the super bowl.

∴ Carolina will win the Super Bowl.

VII. Good Deductive Arguments

The First Type of Goodness: Premises play their function – they provide conclusive logical support.

Deductive and inductive arguments have different aims. Deductive argument attempt to provide conclusive support or reasons; inductive argument attempt to provide probable reasons or support. So we must evaluate these two types of arguments.

Deductive arguments attempt to be valid.

To put validity in another way: if the premises are true, then the conclusion must be true.

It is very important to note that validity has nothing to do with whether or not the premises are, in fact, true and whether or not the conclusion is in fact true; it merely has to do with a certain conditional claim. If the premises are true, then the conclusion must be true.

Q: What does this mean?

• The validity of an argument does not depend upon the actual world. Rather, it depends upon the world described by the premises.
• First, consider the world described by the premises. In this world, is it logically possible for the conclusion to be false? That is, can you even imagine a world in which the conclusion is false?

Reflection Questions:

• If you cannot, then why not?
• If you can, then provide an example of a valid argument.

You should convince yourself that validity is not just about the actual truth or falsity of the premises and conclusion. Rather, validity only has to do with a certain logical relationship between the truth of the premise and the truth of the conclusion. So the only possible combination that is ruled out by a valid argument is a set of true premises and false conclusion.

Let’s go back to example #1. Here are the premises:

1. All humans are mortal.

If both of these premises are true, then every human that we find must be a mortal. And this means, that it must be the case that if Socrates is a human, that Socrates is mortal.

Reflection Questions about Invalid Arguments:

• Can you have an invalid argument with a true premise?
• Can you have an invalid argument with true premises and a true conclusion?

The s econd type of goodness for deductive arguments: The premises provide us the right reasons to accept the conclusion.

Soundness V ersus V alidity:

Our original argument is a sound one:

∴ Socrates is mortal.

Question: Can a sound argument have a false conclusion?

VIII. From Deductive Arguments to Inductive Arguments

Question: What happens if we mix around the premises and conclusion?

2. Socrates is mortal.

∴ Socrates is a human.

1. Socrates is mortal

∴ All humans are mortal.

Are these valid deductive arguments?

NO, but they are common inductive arguments.

Other examples :

Suppose that there are two opaque glass jars with different color marbles in them.

1. All the marbles in jar #1 are blue.

2. This marble is blue.

∴ This marble came from jar #1.

1. This marble came from jar #2.

2. This marble is red.

∴ All the marbles in jar #2 are red.

While this is a very risky argument, what if we drew 100 marbles from jar #2 and found that they were all red? Would this affect the second argument’s validity?

IX. Inductive Arguments:

The aim of an inductive argument is different from the aim of deductive argument because the type of reasons we are trying to provide are different. Therefore, the function of the premises is different in deductive and inductive arguments. And again, we can split up goodness into two types when considering inductive arguments:

• The premises provide the right logical support.
• The premises provide the right type of reason.

Logical S upport:

Remember that for inductive arguments, the premises are intended to provide probable support for the conclusion. Thus, we shall begin by discussing a fairly rough, coarse-grained way of talking about probable support by introducing the notions of strong and weak inductive arguments.

A strong inductive argument:

• The vast majority of Europeans speak at least two languages.
• Sam is a European.

∴ Sam speaks two languages.

Weak inductive argument:

• This quarter is a fair coin.

∴ Therefore, the next coin flip will land heads.

• At least one dog in this town has rabies.
• Fido is a dog that lives in this town.

∴ Fido has rabies.

The R ight T ype of R easons. As we noted above, the right type of reasons are true statements. So what happens when we get an inductive argument that is good in the first sense (right type of logical support) and good in the second sense (the right type of reasons)? Corresponding to the notion of soundness for deductive arguments, we call inductive arguments that are good in both senses cogent arguments.

• With which of the following types of premises and conclusions can you have a strong inductive argument?
• With which of the following types of premises and conclusions can you have a cogent inductive argument?

X. Steps for Evaluating Arguments:

• Read a passage and assess whether or not it contains an argument.
• If it does contain an argument, then identify the conclusion and premises.
• If yes, then assess it for soundness.
• If not, then treat it as an inductive argument (step 3).
• If the inductive argument is strong, then is it cogent?

XI. Evaluating Real – World Arguments

An important part of evaluating arguments is not to represent the arguments of others in a deliberately weak way.

For example, suppose that I state the following:

All humans are mortal, so Socrates is mortal.

Is this valid? Not as it stands. But clearly, I believe that Socrates is a human being. Or I thought that was assumed in the conversation. That premise was clearly an implicit one.

So one of the things we can do in the evaluation of argument is to take an argument as it is stated, and represent it in a way such that it is a valid deductive argument or a strong inductive one. In doing so, we are making explicit what one would have to assume to provide a good argument (in the sense that the premises provide good – conclusive or probable – reason to accept the conclusion).

The teacher’s policy on extra credit was unfair because Sally was the only person to have a chance at receiving extra credit.

• Sally was the only person to have a chance at receiving extra credit.
• The teacher’s policy on extra credit is fair only if everyone gets a chance to receive extra credit.

Therefore, the teacher’s policy on extra credit was unfair.

Valid argument

Sally didn’t train very hard so she didn’t win the race.

• Sally didn’t train very hard.
• If you don’t train hard, you won’t win the race.

Therefore, Sally didn’t win the race.

Strong (not valid):

• If you won the race, you trained hard.
• Those who don’t train hard are likely not to win.

Therefore, Sally didn’t win.

Ordinary workers receive worker’s compensation benefits if they suffer an on-the-job injury. However, universities have no obligations to pay similar compensation to student athletes if they are hurt while playing sports. So, universities are not doing what they should.

• Ordinary workers receive worker’s compensation benefits if they suffer an on-the-job injury that prevents them working.
• Student athletes are just like ordinary workers except that their job is to play sports.
• So if student athletes are injured while playing sports, they should also be provided worker’s compensation benefits.
• Universities have no obligations to provide injured student athletes compensation.

Therefore, universities are not doing what they should.

Deductively valid argument

If Obama couldn’t implement a single-payer healthcare system in his first term as president, then the next president will not be able to implement a single-payer healthcare system.

• Obama couldn’t implement a single-payer healthcare system.
• In Obama’s first term as president, both the House and Senate were under Democratic control.
• The next president will either be dealing with the Republican-controlled house and senate or at best, a split legislature.
• Obama’s first term as president will be much easier than the next president’s term in terms of passing legislation.

Therefore, the next president will not be able to implement a single-payer healthcare system.

Strong inductive argument

Sam is weaker than John. Sam is slower than John. So Sam’s time on the obstacle will be slower than John’s.

• Sam is weaker than John.
• Sam is slower than John.
• A person’s strength and speed inversely correlate with their time on the obstacle course.

Therefore, Sam’s time will be slower than John’s.

XII. Diagramming Arguments

All the arguments we’ve dealt with – except for the last two – have been fairly simple in that the premises always provided direct support for the conclusion. But in many arguments, such as the last one, there are often arguments within arguments.

Obama example :

• The next president will either be dealing with the Republican controlled house and senate or at best, a split legislature.

∴ The next president will not be able to implement a single-payer healthcare system.

It’s clear that premises #2 and #3 are used in support of #4. And #1 in combination with #4 provides support for the conclusion.

When we diagram arguments, the aim is to represent the logical relationships between premises and conclusion. More specifically, we want to identify what each premise supports and how.

This represents that 2+3 together provide support for 4

This represents that 4+1 together provide support for 5

When we say that 2+3 together or 4+1 together support some statement, we mean that the logical support of these statements are dependent upon each other. Without the other, these statements would not provide evidence for the conclusion. In order to identify when statements are dependent upon one another, we simply underline the set that are logically dependent upon one another for their evidential support. Every argument has a single conclusion, which the premises support; therefore, every argument diagram should point to the conclusion (c).

Sam Example:

• Sam is less flexible than John.
• A person’s strength and flexibility inversely correlate with their time on the obstacle course.

∴ Therefore, Sam’s time will be slower than John’s.

In some cases, different sets of premises provide evidence for the conclusion independently of one another. In the argument above, there are two logically independent arguments for the conclusion that Sam’s time will be slower than John’s. That Sam is weaker than John and that being weaker correlates with a slower time provide evidence for the conclusion that Sam will be slower than John. Completely independent of this argument is the fact that Sam is less flexible and that being less flexible corresponds with a slower time. The diagram above represent these logical relations by showing that #1 and #3 dependently provide support for #4. Independent of that argument, #2 and #3 also dependently provide support for #4. Therefore, there are two logically independent sets of premises that provide support for the conclusion.

Try diagramming the following argument for yourself. The structure of the argument has been provided below:

• All humans are mortal
• Socrates is human
• So Socrates is mortal.
• If you feed a mortal person poison, he will die.

∴ Therefore, Socrates has been fed poison, so he will die.

• This section is taken from http://philosophy.hku.hk/think/ and is in use under creative commons license. Some modifications have been made to the original content. ↵

Critical Thinking Copyright © 2019 by Brian Kim 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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Course: wireless philosophy   >   unit 1, fundamentals: introduction to critical thinking.

• Introduction to Critical Thinking, Part 1
• Introduction to Critical Thinking, Part 2
• Fundamentals: Deductive Arguments
• Deductive Arguments
• Fundamentals: Abductive Arguments
• Necessary and Sufficient Conditions
• Instrumental vs. Intrinsic Value
• Implicit Premise
• Justification and Explanation
• Normative and Descriptive Claims
• Fundamentals: Validity
• Fundamentals: Truth and Validity
• Fundamentals: Soundness
• Fundamentals: Bayes' Theorem
• Fundamentals: Correlation and Causation

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Critical Thinking and Decision-Making  - Logical Fallacies

Critical thinking and decision-making  -, logical fallacies, critical thinking and decision-making logical fallacies.

Critical Thinking and Decision-Making: Logical Fallacies

Lesson 7: logical fallacies.

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Logical fallacies

If you think about it, vegetables are bad for you. I mean, after all, the dinosaurs ate plants, and look at what happened to them...

Let's pause for a moment: That argument was pretty ridiculous. And that's because it contained a logical fallacy .

A logical fallacy is any kind of error in reasoning that renders an argument invalid . They can involve distorting or manipulating facts, drawing false conclusions, or distracting you from the issue at hand. In theory, it seems like they'd be pretty easy to spot, but this isn't always the case.

Watch the video below to learn more about logical fallacies.

Sometimes logical fallacies are intentionally used to try and win a debate. In these cases, they're often presented by the speaker with a certain level of confidence . And in doing so, they're more persuasive : If they sound like they know what they're talking about, we're more likely to believe them, even if their stance doesn't make complete logical sense.

False cause

One common logical fallacy is the false cause . This is when someone incorrectly identifies the cause of something. In my argument above, I stated that dinosaurs became extinct because they ate vegetables. While these two things did happen, a diet of vegetables was not the cause of their extinction.

Maybe you've heard false cause more commonly represented by the phrase "correlation does not equal causation ", meaning that just because two things occurred around the same time, it doesn't necessarily mean that one caused the other.

A straw man is when someone takes an argument and misrepresents it so that it's easier to attack . For example, let's say Callie is advocating that sporks should be the new standard for silverware because they're more efficient. Madeline responds that she's shocked Callie would want to outlaw spoons and forks, and put millions out of work at the fork and spoon factories.

A straw man is frequently used in politics in an effort to discredit another politician's views on a particular issue.

Begging the question

Begging the question is a type of circular argument where someone includes the conclusion as a part of their reasoning. For example, George says, “Ghosts exist because I saw a ghost in my closet!"

George concluded that “ghosts exist”. His premise also assumed that ghosts exist. Rather than assuming that ghosts exist from the outset, George should have used evidence and reasoning to try and prove that they exist.

Since George assumed that ghosts exist, he was less likely to see other explanations for what he saw. Maybe the ghost was nothing more than a mop!

False dilemma

The false dilemma (or false dichotomy) is a logical fallacy where a situation is presented as being an either/or option when, in reality, there are more possible options available than just the chosen two. Here's an example: Rebecca rings the doorbell but Ethan doesn't answer. She then thinks, "Oh, Ethan must not be home."

Rebecca posits that either Ethan answers the door or he isn't home. In reality, he could be sleeping, doing some work in the backyard, or taking a shower.

Most logical fallacies can be spotted by thinking critically . Make sure to ask questions: Is logic at work here or is it simply rhetoric? Does their "proof" actually lead to the conclusion they're proposing? By applying critical thinking, you'll be able to detect logical fallacies in the world around you and prevent yourself from using them as well.

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IDENTIFYING ARGUMENTS

8.1 WHAT IS AN ARGUMENT?

In ordinary usage, an argument is often taken to be a somewhat heated dispute 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. An example:

It is raining.

So you should bring an umbrella.

In this argument, the first statement is the premise and the second one the conclusion. The premises of an argument are offered as reasons for accepting the conclusion. It is therefore irrational to accept an argument as a good one and yet refuse to accept the conclusion. Giving reasons is a central part of critical thinking. It is not the same as simply expressing an opinion. If you say “that dress looks nice,” you are only expressing an opinion. But if you say “that dress looks nice because the design is very elegant,” then it would be an argument indeed. Dogmatic people tend to make assertions without giving arguments. When they cannot defend themselves, they often resort to responses such as “this is a matter of opinion,” “this is just what you think,” or “I have the right to believe whatever I want.”

The ability to construct, identify, and evaluate arguments is a crucial part of critical thinking. Giving good arguments helps us convince other people, and improve our presentation and debating skills. More important, using arguments to support our beliefs with reasons is likely to help us discover the ...

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[A09] Good Arguments

Module: Argument analysis

• A01. What is an argument?
• A02. The standard format
• A03. Validity
• A04. Soundness
• A05. Valid patterns
• A06. Validity and relevance
• A07. Hidden Assumptions
• A08. Inductive Reasoning
• A10. Argument mapping
• A11. Analogical Arguments
• A12. More valid patterns
• A13. Arguing with other people

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§1. What is a good argument?

In this tutorial we shall discuss what a good argument is. The concept of a good argument is of course quite vague. So what we are trying to do here is to give it a somewhat more precise definition. To begin with, make sure that you know what a sound argument is.

Criterion #1 : A good argument must have true premises

This means that if we have an argument with one or more false premises, then it is not a good argument. The reason for this condition is that we want a good argument to be one that can convince us to accept the conclusion. Unless the premises of an argument are all true, we would have no reason to accept to accept its conclusion.

Criterion #2 : A good argument must be either valid or strong

Is validity a necessary condition for a good argument? Certainly many good arguments are valid. Example:

All whales are mammals. All mammals are warm-blooded. So all whales are warm-blooded.

But it is not true that good arguments must be valid. We often accept arguments as good, even though they are not valid. Example:

No baby in the past has ever been able to understand quantum physics. Kitty is going to have a baby soon. So Kitty's baby is not going to be able to understand quantum physics.

This is surely a good argument, but it is not valid. It is true that no baby in the past has ever been able to understand quantum physics. But it does not follow logically that Kitty's baby will not be able to do so. To see that the argument is not valid, note that it is not logically impossible for Kitty's baby to have exceptional brain development so that the baby can talk and learn and understand quantum physics while still being a baby. Extremely unlikely to be sure, but not logically impossible, and this is enough to show that the argument is not valid. But because such possibilities are rather unlikely, we still think that the true premises strongly support the conclusion and so we still think that the argument is a good one.

In other words, a good argument need not be valid. But presumably if it is not valid it must be inductively strong. If an argument is inductively weak, then it cannot be a good argument since the premises do not provide good reasons for accepting the conclusion.

For more information about inductive strength, see the previous tutorial .

Criterion #3 : The premises of a good argument must not beg the question

Notice that criteria #1 and #2 are not sufficient for a good argument. First of all, we certainly don't want to say that circular arguments are good arguments, even if they happen to be sound. Suppose someone offers the following argument:

It is going to rain tomorrow. Therefore, it is going to rain tomorrow.

So far we think that a good argument must (1) have true premises, and (2) be valid or inductively strong. Are these conditions sufficient? The answer is no. Consider this example:

Smoking is bad for your health. Therefore smoking is bad for your health.

This argument is actually sound. The premise is true, and the argument is valid, because the conclusion does follow from the premise! But as an argument surely it is a terrible argument. This is a circular argument where the conclusion also appears as a premise. It is of course not a good argument, because it does not provide independent reasons for supporting the conclusion. So we say that it begs the question .

Here is another example of an argument that begs the question :

Since Mary would not lie to her best friend, and Mary told me that I am indeed her best friend, I must really be Mary's best friend.

Whether this argument is circular depends on your definition of a "circular argument". Some people might not consider this a circular argument in that the conclusion does not appear explicitly as a premise. However, the argument still begs the question and so is not a good argument.

Criterion #4 : The premises of a good argument must be plausible and relevant to the conclusion

Here, plausibility is a matter of having good reasons for believing that the premises are true. As for relevance, this is the requirement that the the subject matter of the premises must be related to that of the conclusion. Why do we need this additional criterion? The reason is that claims and theories can happen to be true even though nobody has got any evidence that they are true. If the premises of an argument happen to be true but there is no evidence indicating that they are, the argument is not going to be pursuasive in convincing people that the conclusion is correct. A good argument, on the other hand, is an argument that a rational person should accept, so a good argument should satisfy the additional criterion mentioned.

§2. Summary

So, here is our final definition of a good argument :

A good argument is an argument that is either valid or strong, and with plausible premises that are true, do not beg the question, and are relevant to the conclusion.

Now that you know what a good argument is, you should be able to explain why these claims are mistaken. Many people who are not good at critical thinking often make these mistakes :

"The conclusion of this argument is true, so some or all the premises are true." "One or more premises of this argument are false, so the conclusion is false." "Since the conclusion of the argument is false, all its premises are false." "The conclusion of this argument does not follow from the premises. So it must be false."

Answer the following questions.

• Does a good argument have to be sound? answer
• Can a good argument be inductively weak? answer

These are some arguments (or just premises) that students have given to support the idea that there is nothing morally wrong with eating meat. Discuss and evaluate these arguments carefully. Think about whether the premises are true, and whether they support the conclusion that it is morally acceptable to eat meat.

• Human beings are part of the food cycle of nature.
• Human beings are able to digest meat.
• It is ok to eat meat because meat is just a kind of food and we need food to survive.
• It is ok to eat meat because lots of people eat meat; because everyone around me eat meat.
• It is ok to eat meat because the government does not stop people from eating meat.
• Many other people eat meat.
• Meat contains protein, and we need protein to survive.
• We are animals, and it is ok for animals to eat animals.
• It is ok to eat meat because I started eating meat when I was a child.
• Meat is more tasty than vegetables.
• It is ok to eat meat because nobody told me that this is wrong.
• I love eating meat.
• It is ok to eat meat because set meals in restaurants have very little vegetables.
• Animals kill each other.
• Maintain the balance of nature - there will be too many animals otherwise.
• We are more powerful than animals.
• I was taught that I should eat meat.
• Human beings are at the top of the food chain.
• Eating meat can help me avoid certain diseases.
• We have special teeth for eating meat.

§3. A technical discussion

This section is a more abstract and difficult. You can skip this if you want.

One interesting but somewhat difficult issue about the definition of a good argument concerns the first requirement that a good argument must have true premises. One might argue that this requirement is too stringent, because we seem to accept many arguments as good arguments, even if we are not completely certain that the premises are true. Or perhaps we had good reasons for the premises, even if it turns out later that we were wrong.

As an example, suppose your friend told you that she is going camping for the whole weekend. She is a trustworthy friend and you have no reason to doubt her. So you accept the following argument as a good argument:

Amie will be camping this weekend. So she will not be able to come to my party.

But suppose the camping trip got cancelled at the last minute, and so Amie came to the party after all. What then should we say about the argument here? Was it a good argument? Surely you were justified in believing the premise, and so someone might argue that it is wrong to require that a good argument must have true premises. It is enough if the premises are highly justified (of course the other conditions must be satisfied as well.)

If we take this position, this implies that when we discover that the camping trip has been cancelled, we are no longer justified in believing the premise, and so at that point the argument ceases to be a good argument.

Here we prefer a different way of describing the situation. We want to say that although in the beginning we had good reasons to think that the argument is a good one, later on we discover that it wasn't a good argument to begin with. In other words, the argument doesn't change from being a good argument to a bad argument. It is just that we change our mind about whether the argument is a good one in light of new information. We think there are are reasons for preferring this way of describing the situation, and it is quite a natural way of speaking.

So there are actually two ways to use the term "good argument". We have adopted one usage here and it is fine if you want to use it differently. We think the ordinary meaning of the term is not precise enough to dictate a particular usage. What is important is to know very clearly how you are using it and what the consequences are as a result.

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Critical thinking arguments for beginners

Critical thinking is one of the most valuable sets of life skills you can ever have and it’s never too late to learn them. People who can think critically are better at problem solving of all kinds, whether at school or work, in ordinary daily life, and even in crises. You can practice critical thinking by working through typical arguments from premises to conclusions.

Thinking critically isn’t about following a single path to an inevitable conclusion. It’s about developing a set of powerful and versatile mental processing tools in your head and being able to apply these meaningfully to the world around you.

You need no special qualifications to become a strong critical thinker, and can’t pick it up simply from reading books about critical thinking. The only way to hone critical thinking skills is to practice critical thinking.

If you’re ready to learn more about critical thinking arguments for beginners then read on…

What is critical thinking?

Let’s first illustrate the answer to this question by taking a look at how we can think critically about potential misinformation online.

Your friend on a social media site has shared a photograph of election ballot slips apparently being tipped into a river by a postal truck driver, reportedly a supporter of a political party who will benefit from lower postal voter turnout.

Your friend is a supporter of another party and expresses outrage at the alleged law-breaking, election influencing, and reduced chances for her own party candidate. Many other friends pile in with sympathetic and equally outraged comments, or new allegations.

The temptation might be strong to accept the narrative caption which accompanies the picture, echo your friends’ emotional responses, and share the photo further. However, as a critical thinker, you should step back and ask some crucial questions first:

• Is the photo obviously manipulated? Sophisticated image alterations can now be made which won’t be spotted by the majority of non-experts. Could this be an image of a simple truck crash with ballot papers photoshopped in?
• Does your friend fact-check stories, pictures, memes etc.. before posting them online? If she has a history of posting stories which turned out to be false, it reduces her credibility in presenting the current story.
• I s there anything in the photograph which supports or undermines the claims made? If you can see that the van has a foreign registration plate, the ballot papers aren’t in English, or the date on the clock is actually several years ago, it is clear that the true story is somewhat different to the one being told.

Let’s say that your initial suspicions after asking yourself these questions are enough that you do a quick web search for the story.

Your search reveals that credible sources have already uncovered the photo as having been manipulated and spread by an online political group. It was originally a local news story about a crashed postal truck in another country five years earlier and has no relationship whatsoever to the current election in your country…

Your critical thinking helped you to avoid falling into group-think along with your friends and saved you from spreading more misinformation online. These real life type examples are are an excellent way to grasp the relevance and value of critical thinking arguments for beginners.

Now for a little of the theory. Critical thinking is a description that brings together a range of useful intellectual skills and their synergies. While there is no definitive list, there are some common key competences necessary for critical thinking:

• Conducting analysis. Being able to understand the issue in question; distinguish between relevant and irrelevant information; identify commonalities, differences and connections.
• Making inferences. Using inductive or deductive reasoning to draw out meanings; identifying assumptions; abstracting ideas; applying analogies and recognizing cause and effect relationships in order to develop theories or potential conclusions.
• Evaluating evidence. Making a judgement about whether a theory or statement is credible or correct; adjusting views and theories in the light of new data or perspectives; grasping the significance of events and information.
• Making robust decisions. Reaching sound conclusions by applying critical thinking skills to the available evidence.

To apply critical thinking in real life, you also need to possess the right attitude to problem solving, as well as the critical thinking skills themselves.

This means being automatically inclined to think critically in the face of a difficult question or problem. Being fair, open-minded, curious and free from ideology or group-think will all help to create a mindset in which critical thinking can thrive.

What are critical thinking arguments?

Let’s now look at some of the basic building blocks underpinning critical thinking arguments for beginners.

In critical thinking and logic, ‘argument’ has a particular meaning. It refers to a set of statements, consisting of one conclusion and one or more premises. The conclusion is the statement that the argument is intended to prove. The premises are the reasons offered for believing that the conclusion is true.

A critical thinking argument could use a deductive reasoning approach, an inductive reasoning approach, or both.

Deductive reasoning

Deductive reasoning attempts to absolutely guarantee a conclusion’s truth through logic. If a deductive argument’s premises are true, it should be impossible for its conclusion to be false. For example:

• All humans are mortal. (Premise)
• Socrates is a human. (Premise)
• Therefore, Socrates is mortal.  (Conclusion)

Inductive reasoning

Inductive reasoning attempts to show that the conclusion is probably true, with each premise making the case for the conclusion stronger or weaker. For example:

• Three independent witnesses saw Max climb in through the window of the house. (Premise)
• Max’s fingerprints are on the window frame and several stolen items. (Premise)
• Max confessed to the burglary. (Premise)
• Therefore, Max committed the burglary. (Conclusion)

Do note that in either case, straight assertions, explanations or conditional sentences are not arguments.

How do I assess a critical thinking argument?

You can evaluate whether an argument is valid or invalid, sound or unsound, strong or weak .

If an argument is said to be ‘valid’, it means that it is impossible for the conclusion to be false if the premises are true. If an argument is ‘invalid’, it is possible for the premises to be true and the conclusion false.

An argument is ‘sound’ if it is both valid and contains only true premises. If either of these conditions isn’t met then the argument is ‘unsound’.

A deductively ‘strong’ argument is both valid and it is reasonable for the person in question to believe the premises are true. In a deductively weak argument , the person considering the premises may have good reason to doubt them.

When an argument is inductively strong, the truth of the premises makes the the truth of the conclusion probable. In contrast, in an inductively ‘weak’ argument, the truth of the premises do not make the truth of the conclusion probable.

Counterexamples

A ‘counterexample’ is a consistent story which shows that an argument can have true premises but a false conclusion, rendering it invalid.

NB A valid argument is not necessarily true, and a weak argument is not necessarily false.

All of these fundamentals can be applied both to simple practice arguments and then to more complex problems of the type you might encounter in real life.

For example:

• All unicorns are Swedish (Premise)
• My new pet is a unicorn (Premise)
• Therefore,  my new pet is Swedish (Conclusion)

The premises here are both false – unicorns do not exist, and I therefore cannot own one as a pet. However, if they were true, then the conclusion would be true. What we have here is a valid argument, but not a sound one, nor a strong one.

How can I practice critical thinking arguments for beginners?

Now that you have the basic tools and concepts for putting together a critical thinking argument, you can look  out for real life examples to practice with.

News stories

Look at the headlines covering stories in TV,  online or paper news. Do you agree that the facts of the story are credible and constitute premises strong enough to justify the headline drawn from them?

Social media

Critically examine stories and claims shared by friends and contacts online. Ask yourself whether the evidence presented is credible and justifies the claims being made.

Corporate statements

Evaluate claims made by big corporations in public statements and annual reports alongside their actions and impacts. For example, if a major oil company claims that it is working to combat climate change, how strong, valid and sound are their arguments?

Conclusion…

Whatever your starting point, we hope this article has set you on the road to becoming a critical thinker, and that these developing skills might open new doors at school, at work or in other areas of life. The world needs more critical thinking at all levels and your contribution might one day be valuable.

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2.7: Validity and Soundness

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The idea of a valid argument is one of the most important concepts in critical thinking, so you should make sure you fully understand this topic. Basically, a valid argument is one where the premises entail the conclusion. What this means is that if the premises are true, the conclusion must also be true. So here is a valid argument with two premises and a conclusion:

• Moby Dick is a whale.
• All whales have fins.
• So, Moby Dick has fins.

This is another argument with just one premise and a conclusion:

• Barbie is 90 years old.
• So Barbie is older than 20.

In both of these arguments, if the premises are all true, there is no way that the conclusion will be false. So the arguments are indeed valid. Notice that the validity of the argument does not depend on whether the premise is in fact true. Consider the second argument above. Even if Barbie is actually only a ten-year-old, the argument is still valid. Validity only requires that when the premises are true, so is the conclusion. It depends only on the logical connection between the premises and the conclusion. It does not depend on their actual truth or falsity. A valid argument can have false premises and a false conclusion. A valid argument can also have a false premise but a true conclusion, as when Barbie is 30 years old.

This, however, is not a valid argument. It is invalid:

• Barbie is older than 20.
• So, Barbie is over 90 years old.

The argument is not valid because it is possible that the premise is true and the conclusion is false. For example, Barbie could be 21. Or she could be 80. These situations are counterexamples to the argument. Basically, a valid argument is an argument with no possible counterexamples.To sharpen your skills in evaluating arguments, it is important that you are able to discover and construct counterexamples. Giving a counterexample can help you convince other people that a certain argument is mistaken.

There are a few important points worth remembering:

• An invalid argument can have true premises and a true conclusion. In the previous argument, both the premise and the conclusion are true if Barbie is 99 years old. But remember that true premises and a true conclusion are not sufficient for validity, because the logical connection between them is missing. This means that an argument with true premises and conclusion can still be a bad argument.
• Notice that we are making a distinction between truth and validity. Statements (the premises and the conclusion) can be true or false, but they are not valid or invalid. Arguments might be valid or invalid, but they should never be described as true or false.
• It is possible to have a valid argument where the premises are false but the conclusion is true. Validity only guarantees that when you start with true premises, you end up with a conclusion that is true. So we should never say things like your assumptions are false, so even if you reasoning is logical your conclusion cannot be true.

Given a valid argument, all we know is that if the premises are true, so is the conclusion. But validity does not tell us whether the premises or the conclusion are true or not. If an argument is valid, and all the premises are true, then it is a sound argument. Of course, it follows from such a definition that a sound argument must also have a true conclusion.

In discussion, it would be nice if we can provide sound arguments to support an opinion. This means showing that our argument is valid, and that all the premises are true. Anyone who disagree would have to show that not all the premises are true, or the argument is not valid, or both.

To improve critical thinking, these are good habits to cultivate when it comes to argument analysis:

• Identify clearly the premises of an argument. Can we state the assumptions clearly?
• Check whether the assumptions are true or not.
• Evaluate the validity of the argument. Even if the premises are true, the logical reasoning of the argument can still be quite bad. The evaluation of the premises and the reasoning are two separate tasks.
• When arguing for a certain conclusion, always see if you can find more than one argument to support it. This would make your case more convincing. Being able to count the number of arguments in support of a position is an important thinking skill.

Hidden assumptions

When people give arguments sometimes certain assumptions are left implicit. Example:

• It is wrong to create animals with human DNA because it is unnatural.

This argument as it stands is not valid. Someone who gives such an argument presumably has in mind the hidden assumption that whatever that is unnatural is wrong. It is only when this assumption is added that the argument becomes valid.

Once this is pointed out, we can ask whether it is justified. We might argue for example,that there are plenty of things that are unnatural but are not usually regarded as wrong (e.g.cosmetic surgery, going to the Moon, contraception, etc). Pointing out the hidden assumption in an argument can help resolve or clarify the issues involved in a dispute.

In everyday life, many arguments have important hidden assumptions which have not been made explicit. It is part of good critical thinking to be able to identify these assumptions. One way to do this is to see what additional premises are needed to add to an argument to make it valid.

Bad Critical Thinking Examples: 14 Tips for Better Decisions

Critical thinking is the ability to analyze and evaluate information logically and unbiasedly. It is a skill that can help us make better decisions, solve problems, and avoid fallacies. However, not everyone has good critical thinking skills, and some people may even have bad critical thinking habits that hinder their reasoning. But your Life may full of opportunities and challenges. You can choose to focus on the positive aspects of your life and appreciate what you have. Rather than being a poor reasoner.

Sanju Pradeepa

Thinking critically is essential for success in life, yet it’s not always easy. That’s why so many of us fall back on less effective thinking patterns. But what exactly are these poor critical thinking examples?

In this article, we’ll outline some of the most common examples of poor critical thinking and explain why they don’t hold up to rigorous scrutiny. We’ll also share an actionable approach to help you start thinking more critically and be more successful in your daily life.

So, whether you’re struggling with the idea of critical thinking or have already embraced the concept, read on to find what are bad critical thinking examples, learn some useful tips and insights that can help you become a better thinker.

Table of Contents

What is critical thinking.

Critical thinking is the process of actively and skillfully gathering, evaluating, and discussing information to reach an informed decision or conclusion. It involves analyzing evidence, addressing different perspectives, making connections between ideas, and creating arguments and conclusions.

However, there are some common pitfalls to critical thinking that can prevent you from arriving at the best conclusions.

For example, using overly simplistic solutions to complex problems, such as basing decisions solely on emotions rather than facts and logical reasoning, making assumptions without considering the evidence, or not questioning your own biases,

Ultimately, poor critical thinking skills can lead to rushed decisions that do not fully consider all of the available information or evidence.

As a result, it is important to practice critical thinking regularly to develop strong analytical skills that are necessary for any decision-making process.

Do you know there are some types of Critical Thinking Skills – 7 Types of Critical Thinking: A Guide to Analyzing Problems

Bad Critical Thinking Examples

These examples highlight just how easy it is to get caught up in our own biases rather than relying on facts and data to reach conclusions. So, if you want to practice better critical thinking skills, try to identify these traps before they ensnare your reasoning skills.

1. Substituting Emotion for Reason

Have you ever found yourself substituting emotion for reason? It’s a common mistake. But what does that mean exactly?

It is when you make important decisions based purely on your feelings, rather than on facts and logic. Your emotions may tell you something’s wrong, but if you don’t use facts to back up your feelings, chances are you’re making an ill-informed decision.

One example of substituting emotion for reason is forming an opinion about someone else’s choices without considering their point of view. In this situation, you may have a strongly held belief about how certain scenarios “should” turn out, but if you don’t consider the other person’s reason for making their decision, you could be missing key information.

This might look like deciding something before considering all of the evidence or relying on assumptions instead of facts.

Tip – The best way to avoid substituting emotion for reason is to take a step back and ask yourself, “Am I looking at the whole picture?” If not, use critical thinking skills like fact-checking or asking questions to gain a more complete understanding of the situation.

With an open mind and an objective approach, it’s possible to make decisions based on facts instead of feelings.

2. Jumping to Conclusions Without Evaluating Evidence

It’s easy to come to a conclusion based on assumptions rather than facts and reasoning.

Let’s say someone told you that Bob always arrives late for work. Without looking into the evidence, you might assume he’s lazy and not a team player. But after looking at the evidence, for example, if Bob was in a car accident or his commute was particularly long that week, you’d realize there were other factors at play here.

So what can we learn from this? Well, it comes down to seeing things from multiple perspectives and understanding there may be more than one explanation for something. Before concluding,

Tip – It’s important to evaluate the evidence surrounding it and consider all possible factors influencing the situation. This way, you can get closer to the truth rather than making assumptions based on an incomplete picture.

3. Ignoring Information and Facts

You might not know this, but one of the most common examples is ignoring information and facts. It’s like you have blinders on and you’re determined to stick to your own opinion no matter what, even though there is evidence that contradicts it.

Ignoring important information and facts is bad news because facts are the foundation of critical thinking. If you don’t consider relevant data when reaching a conclusion, then you can’t have an accurate opinion; it will just be based on assumptions and your own biases. 

Tip – So, here are some things to look out for when it comes to avoiding this mistake:

• Don’t dismiss facts that are presented by people who present them in an unfamiliar way, even if the information seems overwhelming or confusing at first glance.
• Consider all angles of a situation before making an opinion or forming an argument.
• Don’t take things at face value; check sources, view multiple perspectives, and try to find reliable sources for your beliefs.
• Don’t be afraid to ask questions or seek out people with different perspectives to better understand the issue at hand.

“The unexamined life is not worth living.”  Socrates

4. Not Considering Other Perspectives

Another thing to consider when it comes to poor critical thinking is failing to consider other perspectives. After all, if you’re not taking the time to look at things from different angles, then you are limiting yourself .

For example, say you’re trying to come up with solutions for a problem at work. You might think that the first solution you come up with is the best one. But if you take the time to really brainstorm and consider other perspectives and options, then you might find a better solution.

Assumptions: It’s easy when dissecting an issue to assume that other people’s ideas apply only to them and not necessarily to everyone. Not considering other perspectives oftentimes results in making false assumptions about someone else’s ideas or beliefs. These assumptions can lead to miscommunication or worse.

Ignorance: Not listening and attempting to understand other perspectives can also lead to ignorance. Rather than trying hard to understand how someone else thinks or believes, we can stick with our narrow view of the world and be closed off from new information and experiences that could benefit us in some way. 

By not taking the step of trying to engage with different points of view, we risk missing out on important insights and valuable context that can help us make more informed decisions or form a deeper understanding of an issue or situation.

Tip – So next time you’re approaching an issue or problem critically, try zooming out and looking at things from multiple angles. You’ll soon see why it pays off.

5. Overgeneralizing

This is when you take a single experience or observation and use it to draw conclusions about an entire group or situation. People might do this when they oversimplify their views instead of looking at all the evidence and weighing it up objectively first.

Let’s look at this with an example: You see a tourist asking for directions, and the person who helps them gives some very helpful advice. You might think that all tourists are friendly, but this isn’t necessarily true; you don’t have enough evidence to make such a broad assumption.

Tip – The next time you think of making a snap judgment call about something, consider taking the time to look at all sides of the story first before coming to any conclusions.

6. Neglecting Creative Thinking

Poor critical thinking examples can also include neglecting to come up with creative ideas or solutions. It’s great to be able to analyze a situation and make decisions based on facts, but sometimes it’s just as important to challenge the status quo and come up with new, innovative solutions.

Creative thinking is about being able to blend facts and existing ideas together in a way that produces something new, is more effective, or increases efficiency. Neglecting this form of critical thinking can lead to missed opportunities as well as poor decision-making.

It helps you assess a situation from different angles and perspectives. It’s not enough to just identify the problem; you have to find a solution that works best for everyone involved. 

Tip – Here are some ways you can start incorporating creative thinking into your problem-solving:

• Brainstorming: Give yourself time to think of different approaches and techniques.
• Incorporating input from others: Get feedback from others who are knowledgeable about the issue.
• Identifying trends: look for patterns that could inform your approach.
• Re-framing the problem : ask yourself if there is another way you could interpret the issue.
• Experimenting: Try different methods until you find one that works best.

7. Listening to Biased Sources

When it comes to critical thinking, one of the biggest mistakes you can make is listening to biased sources. They are ones that already have an agenda when it comes to your opinion. They want you to believe a certain way, and they’re going to do whatever they can to make that happen.

This kind of source will often present “facts” in a way that skews your perspective, and even if they’re telling the truth, they’ll leave out important context. This is why it’s always important to find multiple sources and look at the information objectively.

Here are some red flags that might tip you off when someone is being biased:

• They use inflammatory language or negative stereotypes .
• They cherry-pick data and leave out essential context.
• Their arguments rely more on personal attacks than on facts.
• They bring up irrelevant topics just to distract from the facts.

Tip – If you start seeing any of these signs, it’s time to take a step back, recognize what’s happening, and look for more reliable sources instead. Remember: critical thinking requires an open mind and plenty of research.

8. Confirmation Bias: Seeking Data That Confirms Your Own Beliefs

Another critical thinking error is confirmation bias. This typically happens when you’re trying to prove a point you already believe in and only seek out or interpret data that confirms what you already think.

For example, if you happen to be a firm believer in the benefits of the keto diet but are presented with evidence that shows the diet is bad for your health, chances are your confirmation bias will kick in. You’ll ignore or discount the evidence and instead look for data that confirms your own beliefs .

Tip – Confirmation bias can happen through a deliberate attempt to ignore contradictory information. The result is that you end up creating a false illusion. All the information out there supports your beliefs. So be aware of every step when making decisions and act accordingly.

9. False Dilemma

This is when someone presents two options as if there were no other alternatives, but usually there are more options than just those two.

For example, say a member of your team tells you that you have to either choose her idea or put the project on hold. This is a false dilemma; in reality, the project could move forward using some combination of ideas from all members of the team.

Tip – False dilemmas are sometimes used to manipulate people into making decisions they wouldn’t otherwise make. If someone ever presents you with only two options and claims that it’s an either/or situation, be sure to stop and think critically about whether or not there are truly any other possibilities.

10. Straw Man Argument

A straw man argument is a logical fallacy that involves misrepresenting or distorting an opponent’s position to make it easier to refute. It’s a common tactic used to make an argument look stronger than it is.

It’s important to remember that using straw man arguments does not help support an argument; rather, it detracts from its validity and damages its credibility. 

Tip – The best way to win an argument is to focus on the facts and present well-thought-out evidence in support of your positions rather than resorting to logical fallacies like the straw man argument.

11. Slippery Slope Fallacy

The slippery slope fallacy is a particularly dangerous one to make in critical thinking. It’s an attempt to predict a seemingly inevitable outcome from a supposed “first step.” When you use this fallacy, you might find yourself saying something like, “If A happens, then it’s only a matter of time before Z happens; obviously, A must be prevented.”

This type of reasoning is usually flawed because it ignores reality. For example, if someone argues that legalizing marijuana will inevitably lead to addiction and economic ruin, they are ignoring the fact that there are several factors at play, not just the legalization.

Tip – It’s important to avoid this fallacy when critically examining an argument because it can often lead people astray or cloud their judgment. Make sure to check your premises carefully and ask yourself if what you’re saying is based on reality or just speculation.

12. Expecting Perfection or the Impossible

A common mistake people make when trying to think critically is expecting perfection or the impossible. This occurs when a person outlines a goal that is either unattainable or not completely realistic.

For example, someone might set out to solve a complicated problem in one day, even though it requires time and effort to build up the skills or resources needed to get the job done. Instead of setting themselves up for failure from the beginning, they should break down the problem into smaller, more attainable tasks.

It’s important to recognize that critical thinking isn’t about being perfect; it’s about understanding your limitations and working within them to come up with creative solutions.

Letting go of expectations that are unrealistic or unattainable will help you become a better problem solver and critical thinker.

13. Misinterpreting Data and Statistics

When it comes to critical thinking, data, and statistics, they don’t lie, or do they? Unfortunately, many times people misinterpret data and statistics, which can be a major critical thinking mistake.

Take the example of a study that claims eating pizza is healthier than eating chicken. Sure, that could be true based on this particular study. But without looking further into the details of the study, such as the number of participants or sample size, you can’t form an accurate opinion.

Drawing Conclusions Too Quickly: It’s important to analyze background information and other data points in order to draw more meaningful conclusions. Without looking at the complete picture, you could come away with a conclusion based solely on surface-level information that just isn’t accurate.

Drawing the Wrong Conclusions: Critical thinking is key here. While one might conclude that pizza is healthier than chicken from the first example, it’s possible that there were elements of bias in the study. well-rounded.

Tip – Do not jump to conclusions or accept claims without evidence. Look for patterns, trends and outliers in the data. Ask questions and seek explanations. Evaluate the arguments and evidence from different perspectives.

14. Circular Reasoning

If you’re not familiar, this is a logical fallacy where the argument doesn’t have any actual basis or supporting evidence.

Instead, it just keeps going around in circles, with the conclusion supporting the same premise that was already established in the original statement. It’s an assumption masquerading as an argument.

So how can you recognize this fallacy when you see it? Here are some common examples:

• “People should obey the law because it is the law.” This statement presumes that people should accept and obey laws simply because they exist. There is no further explanation or evidence provided as to why they exist or why they should be obeyed.
• Circular reasoning provides a false sense of security. It might sound convincing at first, but when you look at it, you’ll quickly see that there’s no real evidence or supporting facts behind it. Critical thinkers recognize this practice for what it is: an invalid argument that’s desperately trying to pass itself off as convincing logic.

Tip – To avoid circular reasoning, one should provide independent evidence or reasons to support the conclusion, and avoid restating the conclusion in different words.

Examples of Poor Reasoning

Critical thinking doesn’t always get the best press, and that’s probably because it gets abused. Poor critical thinking is littered with fallacies, confirmation biases, and leaps of logic that make it a frustrating affair.

We often see Bad critical thinking in everyday life. Here are some examples:

• jumping to conclusions and reaching a decision too quickly without considering all of the evidence.
• overgeneralizing and drawing broad conclusions from a single event or data point
• Selective Thinking Focus on selected pieces of evidence that support your position and ignore other information.
• Emotional reasoning: making decisions based on how you feel rather than facts and logic.
• Ad hominem attacks attack someone personally to invalidate their arguments instead of focusing on the argument itself.
• False dilemma: assuming there are only two possible sides to an issue or two possible outcomes when in reality there are more options or scenarios.

In conclusion, examples of bad critical thinking can be found in many aspects of our lives, such as politics, media, education, and personal decisions. They can lead to faulty reasoning, biased arguments, fallacious claims, and poor judgment.

To avoid bad critical thinking, we should always question our assumptions, seek evidence, consider alternative perspectives, and evaluate the consequences of our actions. By doing so, we can improve our thinking skills and make better choices for ourselves and others.

• When Critical Thinking goes wrong – There is a fragile line between Critical thinking and Overthinking. by Hoang Nguyen Published in Prototypr
• No Such Thing as ‘Good’ Critical Thinking – A process outline of what it means to be a critical thinker. by Christopher Dwyer Ph.D. (2018) published in Psychology Today (https://www.psychologytoday.com/)
• Risks Associated with Weak Critical Thinkers from Insight Assessment (https://www.insightassessment.com/)

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17 Generalizing

Dale hample and yiwen dai, 1. preliminaries [1].

Arguments manage meanings. Normally an argument begins with something that is already known or agreed upon, and then proceeds to a conclusion that is “new” in some sense. This movement from given to new is characteristic of all social arguments. The only exception might be perfectly deductive arguments, where all the information is already understood to be contained somehow in the premises. Informal (or social) arguments involve some sort of inference, a going-beyond what is strictly expressed in the premises. By moving to a new proposition or thought, the argument can create a new meaning for someone, or reinforce an old meaning, or refute an inappropriate meaning. Arguments manage meanings.

One particularly valuable sort of meaning is a generalization. A generalization summarizes or characterizes material that is more singular than it is. If the singular things are few and straightforward, the generalization isn’t especially useful (e.g., “My parents both like fruit pies” isn’t much more convenient than “Mom and Dad both like fruit pies”). But the real value (and threat, but we will come to that when we discuss stereotypes) of a generalization is when it does a lot of work by summarizing too many things to think about at once (e.g., “Some thoughtful adults in nearly every human generation and culture have complained that younger people are lazy and self-centered”).

Generalizations are often involved in arguments, and we can distinguish several kinds of such arguments. Some arguments move from singular premises to a more general conclusion. This involves arguing from examples or doing some approximation of scientific induction. For example, “In my survey, most people who were high on dogmatism were also high in authoritarianism; so dogmatism and authoritarianism are positively associated.” We will call these generalization-establishing arguments. Other arguments have a generalization in the premises, but still move to a singular conclusion (you know one famous example like this: “All men are mortal; Socrates is a man; so Socrates is mortal”). We will call these generalization-using arguments. Finally, some arguments contain nothing but generalizations. For example, “everyone acts from self-interest; all self-interested actions damage social cohesion; therefore everyone damages social cohesion.” We will call these generalization-saturated arguments. We will discuss all these, but will have the most to say (by far) about generalization-establishing arguments.

As for other social arguments, we have four measures of evaluation available to us. These are criteria that one can use to evaluate the argument’s strength or cogency. The first three are the ARS considerations, originated by Anthony Blair and Ralph Johnson. The argument’s premises must be acceptable (A). They must be true, or probable, or plausible, or agreeable in some respectable way. If at least one key premise fails this test, the argument is poor. The conclusion might still be true by accident, but that argument will not have supported it. Second, the premises must be relevant (R) to the conclusion. Relevance is a little hard to define precisely, but the idea is that premises must bear on the conclusion, so that if the premises are true a reasonable person becomes more comfortable with the conclusion. Relevant premises assert something that is an element of the conclusion or that implies something about the likelihood of the conclusion. S stands for sufficiency . The idea here is that all the premises together are enough to prove the conclusion. One can have what is called a convergent argument that contains perhaps four individually flawed reasons for the conclusion. One at a time each reason could be set aside, but when they are combined they make a jointly suitable case for the conclusion. Sufficiency and necessity are different, by the way, and they are sometimes confused. Sufficient premises are enough to prove a conclusion. Necessary premises are required for a conclusion to be so. A premise can be necessary without being sufficient (“You have to study a lot in order to graduate”). A premise can also be sufficient without being necessary (“People lucky enough to win the lottery end up being rich”). Sufficiency is the third criterion, not necessity.

The fourth criterion is what Ralph Johnson called the dialectical tier of argument. Acceptability, relevance, and sufficiency are all internal to the argument. They are about the premises and the argument scheme. The dialectical tier is external to it. “Dialectic” describes an exchange between two ideal arguers who marshal their reasoning skills, commitment to the truth, and their knowledge of the world to come to a conclusion. When thinking about the dialectical level of argument evaluation, we ask ourselves what else in the world—external to these premises—might bear on the conclusion. So someone might present us with an argument for Western European military intervention into Turkey. Even if the premises about Western Europe and Turkey seemed acceptable, we would be entitled to object to the argument if it didn’t take Russia into account at all. Refutative arguments, exceptions, and counter-examples take their place on the dialectical tier.

We will be using these four standards—acceptability, relevance, sufficiency, and dialectical quality—as we work through the various ways generalizations fit into arguments. Generalization arguments are as likely to go bad as any other kind of argument, but these also hold out the special danger of stereotyping. So as we move along we will pause to give particular attention to the possibility that arguments contain racism, sexism, religious intolerance, damaging views about other people’s identities, and similar sorts of things. Stereotypes and generalizations can be hard to distinguish in a technical way. We will loosely say that stereotypes are generalizations that express unjustified hate, offense, or devaluing of some group of people, and not pursue definitions any further than that. (Actually, some stereotypes can be positive, as with a favorable view of everyone representing your political party, but we will neglect that possibility here.) As the United States Supreme Court ended up saying about pornography in the 1964 case Jacobellis v. Ohio , “I know it when I see it.” We will organize the rest of the chapter by reference to the ideas of generalization-generating, generalization-using, and generalization-saturated arguments.

2. Generalization-establishing arguments

We begin with arguments that move from premises about specific cases to a summative conclusion that groups the cases together and offers some statement about the group. For example, “Uncle Ed is a schmuck; Aunt Raby is dumb; cousin Edward can’t count yet and he is 8 years old; cousin Edie won’t read a book unless you pay her; these are most of my relatives on my father’s side; so my father’s family is pretty hopeless.” This argument moves from specifics (Uncle Ed, Aunt Raby, etc.) to a group (my father’s family) and makes a remark about the group. Notice that the example also collects various descriptions (schmuck, dumb, can’t count, won’t read) and composes them into a summary (pretty hopeless) that is an idea that not only collects but also extends the implications of the specific descriptions. So there are actually two sorts of generalizing going on here. The first is like induction, where individual cases are examined and a probabilistic conclusion is drawn about the class of cases. The second is a kind of argument by composition, where attributes of some more general characteristic are sampled and a conclusion is drawn about the general characteristic. These two sorts of generalization don’t always have to be present together, but they often are. They are quite likely to be involved in evidence offered for stereotypes.

Just by using common sense, we can immediately see opportunities to criticize this argument. We might think along these lines:

A cceptability : Are these attributes (schmuck, etc.) really true about each case (Uncle Ed, etc.)? Or are they perhaps just a series of poorly supported impressions? What’s the evidence? Does everyone (or informed people, or smart people, etc.) see these people this way?

R elevance : Do these attributes (schmuck, etc.) really bear on the conclusion about the group (pretty hopeless)? Are these four people really “most of” the people in the group mentioned in the conclusion? Are these four people typical of everyone in your father’s family? You are in your father’s family, too, for instance.

S ufficiency : Is it possible for the attributes to be true and relevant, but the conclusion to be wrong? That is, does more need to be known before the conclusion can be fairly drawn? Are the named attributes (can’t count, etc.) keys to the conclusion (pretty hopeless)? That is, do they “add up” to the conclusion?

D ialecti cal T ier : Do these people have other, more wonderful, attributes? Or even more awful characteristics? Is “pretty hopeless” too strong a characterization? Too weak? As a matter of fact, what could “hopeless” mean in this sort of context, and can we define and defend the core idea of “pretty hopeless?”

Perhaps you can immediately see the usefulness of our little system of four criteria for evaluating an argument. We had some trouble deciding where to put the question about what “pretty hopeless” means, by the way. The component meanings in an argument need to be clear before you can really think about any of the ARSD standards, so the question of clarity actually appears at any time you are trying to evaluate anything that bears on the term. We put it in Dialectical Tier mainly because it seemed a little philosophical. You don’t need to do the ARSD thinking in any particular order anyway.

We started with what we thought might be a recognizable sort of example so that you can see where we are going with all this. But now we want to get a little bit more sterile in order to clarify some of the standards for this sort of argument. By looking at the most formally developed ways to establish a generalization, we should see the principles at work in more ordinary arguments too. We are going to abandon the argument-by-composition feature and just concentrate on induction-like sorts of generalization. You will encounter many examples of this when you read about public opinion or scientific investigation.

Let’s begin with public opinion polling. If you are interested in public affairs, nearly every week you will read about some poll that summarizes (i.e., makes a generalization about) public views of a politician or policy. Some of these polls are now labeled “unscientific” by the media that report them. Often the media also report that results have a “margin of error,” perhaps plus or minus 5%. We will explain these things as we go. Younger readers may not appreciate that neither of these things—acknowledgement that a poll is unscientific, notice that the results are not precisely accurate—used to be done, and that these are improvements in journalism during the last half century. Even now, however, the media do not always report the exact question they are summarizing, which is really essential to evaluating their generalization.

Two of the key preliminary steps in conducting a poll are to write the questions and select the sample. The question needs to be such that it will get the pollster an accurate answer, and that means that it must address the subject matter without any imbalance. For example, you will get different answers to these pairs of questions:

• “Do you think that women have a right to choose what happens within their own bodies? / Do you think that women have a right to abort their fetuses?”
• “If a drug would save 200 lives out of 600 very sick people, should we administer it? / If a drug would kill 400 people out of 600 very sick people, should we administer it?”
• “Do you think that everyone, regardless of race or other identity, should have an equal chance to succeed in life? / Do you think that affirmative action programs are justified?”

It’s possible that a particular person might think that the first question in each pair has the same meaning as the second one. (It’s also possible that someone is trying to rig a poll to mislead the public into committing the bandwagon fallacy, or is actually using the poll as a persuasive device by getting people to agree to certain things out loud.) But the questions are probably going to register differently with people, emphasizing one element of the issue more than another or using some vague but hard to question phrase (“right to live,” “equal chance,” etc.). When the media report the question, viewers are better positioned to evaluate the poll. But often the media will “summarize” the question for their audience, reporting either half of the first pair as “attitudes toward abortion,” or either half of the third pair as “approval ratings for affirmative action programs.” Professional political pollsters have quietly decided to use the same question phrasing from poll to poll and from political party to political party, so that their clients can actually compare themselves to opponents and past results. Even if the standard question is flawed, at least the same flaw will be propagating through everyone’s data, and that makes the results more useful. Data doesn’t have to be perfect to be valuable: it merely has to have a known level of accuracy.

Oddly, that brings us to the second preliminary matter, selecting a sample. A perfect statement about what the citizens of Mexico think about Mexican tax rates would be to ask every single Mexican citizen, and report the answer. This would be a census, not a sample. Samples are used because they are cheaper and faster than taking a census. A sample of Mexican citizens imperfectly represents the whole population of Mexican citizens, but the degree of imperfection is known—provided that the sample is done in a particular way. This is where the “margin of error” comes from. To get a known margin of error, the pollster needs to collect a random sample of the population. A “random sample” means that every person in the population has an exactly equal chance to be in the sample. To assure this (well, to approximate it, really), polling firms might use lists of people (perhaps everyone who voted in the last Republican primary, or everyone living in an apartment building, or everyone with a driver’s license in a particular state or province, depending on the population one wants to generalize to) and choose people for the sample by using a random number generator. If the random number generator’s first result is 546, the 546 th person on the list is contacted, and so on. The list is the population (technically, it is the “sampling frame”), and the sample result is intended to generalize to that population. Sometimes pollsters will just randomly generate telephone numbers within particular area codes so that they can cover cell phones and unlisted numbers. The size of the population is known, either from the list of voters or the number of possible phone numbers, and the size of the sample is also known. Provided that the sample was drawn randomly , we can calculate or just look up the margin of error.

On the next page is a standard table [2] that shows some benchmark values. The population size is the total number of people on the list, in the country, etc. It is how many people would be in a census of that sort of person. The sample size is the number of people who were actually polled. The margin of error is the plus or minus estimate of how accurate the poll’s answer would be (e.g., “54% of people approved, plus or minus 5%”). The confidence in the margin of error is how sure you are that the true answer will actually be within 5% or whatever the margin of error is. (Technically the confidence statistic is not a summary of people’s subjective feelings. It is a statistical calculation of how often the percentage of results would be within the margin of error if an infinite number of samples of that size were drawn from a population of that size.) Media aren’t to the point of reporting this fourth thing yet, but as more people become better educated, perhaps they will start.

The table’s information is interesting, and runs counter to many people’s intuitions. Sometimes people will hear about some poll (inevitably, one whose result is annoying), and will dismiss it, saying something like, “How can 400 answers tell us what two million people think?” The table is right and that intuition is wrong. With small populations (the example in the table is 100), you really do need to survey nearly everyone to get very close to an accurate answer. Just to get within an error margin of 5% (with 95% confidence in that 5% margin), you need to get 80 out of 100 people in your sample. If you wanted 99% confidence in a 3.5% margin of error, you would need 93 people. This is where people’s intuitions come from, we suppose. But with larger populations, you need much smaller percentages. You would only need 384 people out of a million to have 95% confidence in a 5% margin of error (that’s about .04% of the population). And with a population of 300 million (almost the whole population of the U.S.A.), you don’t need any more people in your sample than you did for a one million population. So there are enormous economies of scale in doing this sort of sampling.

But we emphasize: the results in the table only apply to perfectly random sampling. We tend not to worry very much about tiny imperfections, like missing people who lost their cell phone that day or other little flukes of everyday life. Those are technical violations of random sampling but they probably have negligible effects on the results, because they are non-systematic. That is, we can assume for instance that an equal number of Republicans and Democrats probably lost their cell phone that day. But when the violations are systematic, that is when the media have to call the poll “unscientific.” For example (this is the usual one), a TV network might put a poll up on the Internet during the newscast and invite people to respond. The only people who respond are those who are watching that network at that particular time, who have Internet access at that moment, and who are highly motivated. If the poll result is accurate that is purely by accident, and there is no way to calculate things like margin of error—because all the statistical theory requires random sampling to have been done.

So random sampling is the gold standard for knowing how much inaccuracy there is . It isn’t necessarily the gold standard for getting the most accurate results or getting them most efficiently. At least two other sorts of sampling are common in scientific investigations and both should be respected provided that they are done properly. Strat i fied random sampling is done when the population is divided into strata (or subgroups), and each stratum is then sampled randomly. Suppose that your population was all the children in your community playing a youth sport. Your strata might be 6-9 year olds, 10-12 year olds, and 13-16 year olds, because that’s how the sports are organized, and you know that these age groups of kids are very different in many ways. Within each age group you would sample randomly. The advantage of this is that, because you assume that the children’s age will be important to their answer, you have made sure that each age group is properly represented in your sample. That makes your overall result more accurate. However, it sacrifices your ability to say that your overall result has a specific margin of error, because it is not a random sample of the whole population. Cluster random sampling is another high quality sampling procedure. This time instead of dividing your sample into some interesting strata, you divide them up, usually geographically. So you might get a map of your city, mark off and number all the city blocks, and then randomly choose a certain number of blocks. That makes it efficient to gather your data: you simply drive to one block, park your car, and go home to home (or you could randomly sample within each block), and then drive to the next block on your list. This efficiency is paid for by some possible sacrifice of accuracy, because you might miss some interesting city blocks this way (maybe many of the elderly people live in one section of the city that has retirement homes or some minority is clustered, and you under- or over-represent them). These two kinds of sampling are rarely mentioned in the media, and you are mainly likely to encounter them if you are reading original research papers. For public use, most of what is done and reported is simple random sampling, and you should pay attention for any indications that it has been done inappropriately.

Polls, as we said, are intended to produce some generalization about what the public thinks. They move from individual answers to a generalized summary. Let us consider some of the ways one might argue for such a generalized summary.

• You could ask your best friend, who says taxes should be lowered, and then announce that the public thinks taxes should be lowered. This can actually happen if you were talking to someone you really respect, like a parent or professor, and you don’t stop to think about what you’re doing. It is a pretty bad argument. It might be called anecdotal evidence or overgeneralization. The problem is that the evidence in the premises isn’t sufficient to support the conclusion.
• You could interview a hundred people in the shopping mall, average their answers, and announce that 62% of all citizens think taxes should be lowered. This is “unscientific” because it isn’t a random sample. You don’t have any way to estimate margin of error. And you misstated your conclusion: you have no right to say anything about “all citizens” because your population was “people in the mall on Thursday night.” And you didn’t even randomly sample them. Your data is barely relevant to a conclusion about “all citizens,” and certainly not sufficient to support any answer as specific as 62%.
• You can do (or hire) a professional survey that starts with a good population list, samples it randomly, and obtains a large enough sample to report that 55% of the citizens think taxes should be lowered, plus or minus 4%. If the scientific procedures are followed properly, we really only need to worry about whether the question was neutrally worded.

To this point, we have been discussing public opinion polling, which is a way to generalize views (or habits, or intentions, etc.) of people. This is very common in political affairs and even has some prominence in economic news (consumer confidence, wholesale orders, etc.). It is also the source of many conclusions about correlations, for example, that extroversion is positively correlated with a satisfying social life. Polling—or to be more general, surveying—involves observation of what is naturally happening. Experiments, in contrast, intervene into what is naturally happening and make generalizations about what happens as a result.

4. Experiments

In the past decades we have seen more and more media reports about experiments, especially about medical things. As people have become more sensitive to the sources of medical and nutritional advice, they have wanted to know something about the research basis of recommendations about whether they should use butter or margarine, whether coffee is healthy or deadly, what pills to take for arthritis, and so forth. The media have obliged by summarizing experimental research and conveying its generalizations to us. As practicing social scientists who actually conduct and publish experiments, we are often upset at what gets left out of these journalistic reports and what phrasing is used to replace the scientists’ careful statements. You should learn to read the original reports for yourself if you are truly interested in the topic. Here, let us outline some basic ideas that will help you evaluate the generalizations that are drawn from experiments. These are issues that you should deal with yourself when you are reading the original reports, or suspicions that you should have when you are reading a summary of the reports that does not mention these matters.

An experiment differs from a poll in several fundamental ways because an experiment is straightforwardly designed to discover causality. In polls and surveys, everything co-occurs: causes, effects, and epiphenomena are mixed together; one cannot discern what things changed first and what things changed later; and one can only see the detritus of causal processes but not the causal processes themselves.

Experiments address these issues with several design features. (1) There is always at least one comparison group. Two or more groups with different histories (histories that are hypothesized to differ in a causal-process-relevant way) can be compared on a key outcome measure. The outcome measure is often called the dependent variable because its value depends on earlier causal dynamics. Sometimes it is called the criterion variable. (2) The timing of events is known. This is because the experimenter initiates a key change for the “experimental” group. (3) This change is the experimental manipulation. The experimenter interferes with the usual order of events by changing something artificially. In most social sciences this is called the manipulation because the researcher manipulates the value of the causal (independent or predictor) variable. In economics this would be called a shock to the system, which is a nice metaphor for what the experimenter does to the otherwise stable causal field. (4) Membership in the two (or more) groups to be compared is determined by random assignment. Random assignment is different than random sampling. In random sampling, everyone in the population has an exactly equal chance to be in the sample. In random assignment , everyone in the sample has an exactly equal chance to be in group 1 or group 2, and so forth. Even if the sample was not drawn at random, a study can still have random assignment. So out of a group of volunteers (not a random sample of the population) an experimenter could randomly assign some to eat from one diet and the others to eat from another diet. Many descriptions of experimentation only emphasize two of these elements, manipulation and random assignment, but it is just as well to spell out the other items in order to appreciate how experiments generate generalizations.

For a simple design, an experimenter’s argument goes like this. “I originally had two groups that were originally comparable in every important respect. I did not measure ‘every important respect’ because no one can think of all of them. Instead, I relied on random assignment to equalize the groups. With large enough sample sizes, random assignment will even out everything between the groups, even the things that aren’t actually relevant. Then I intervened into the natural order of things by manipulating one of the groups’ drug regimen (or their internet access, or the amount of sugar they ate, etc.). I then waited a scientifically justifiable length of time and accurately measured their health (or weight, or level of depression, etc.). I detected a difference between the two groups’ average level of health (or weight, or depression, etc.) and applied proper statistical procedures to judge whether the difference was either dependable or so small that it might have occurred by chance. It was ‘statistically significant,’ meaning that it was large enough that it was unlikely to have happened by chance (this is the p < .05 standard). Since the difference between the two groups was statistically significant, I went on to calculate the effect size of this difference. This leads me to conclude that in this study, the experimental group (the one that got the manipulation) had X% better health. Therefore the manipulation causes better health to X degree.”

In evaluating a study like this one, there are two categories of concern. These are internal and external validity. The classic treatment of these matters was written by Donald Campbell and Julian Stanley. These validity matters can be broken down into ARSD issues, and this would be an interesting exercise. But since there are well developed vocabularies for these two kinds of study validity, we will use those. Pure experiments are actually not vulnerable to internal validity problems because they were designed to avoid such critiques. But since every real-world experiment has some approximations and corner-cutting, we will cover those issues anyway.

For internal validity, the basic question is, “Are we sure that we understand the causal dynamics within the experiment?” In other words, if we observed a difference between the two groups, are we sure that the difference was due only to the experimental manipulation? Setting aside obvious impurities such as we see in movies (e.g., an evil doctor messing with the medicines, an unscrupulous Senator getting his daughter into the treatment group, etc.), here are the standard internal validity issues: history, maturation, testing, instrumentation, statistical regression, selection biases, experimental mortality, and selection-maturation interaction. History refers to outside events that might have affected results. For instance, during World War II sugar was not ordinarily available in England and that would have affected a diabetes experiment that began in 1935 and ended in 1945. Maturation refers to the natural growth and development of study participants due to time passage and time passage alone. For instance, in a long-term study of adolescent drug usage the participants would get older and perhaps wiser. Maturation could also happen in relatively short-term studies. For example, participants might become tired or hungry during a two-hour experiment. Testing refers to the possible effect of taking a test once on taking it again. For instance, if students are given the same math test at the end of every week they might eventually learn to answer those exact questions. Instrumentation has to do with inadvertent changes in the measurements. For instance, a new set of counselors might be brought in partway through a study to evaluate depression levels, and they could use different standards. Statistical regression happens when groups with extreme characteristics move toward more ordinary values. For instance, if a group of extremely obese people were in a weight-loss study, some of them might naturally lose some weight over time because there is not much room to gain more weight. Selection biases have to do with who gets assigned to the groups. In other words, participants in the experimental group may differ from those in the control group to begin with. For instance, if study administrators make sure their friends get into the treatment group, this would make the two groups incomparable. Experimental mortality refers to differing levels of dropout in the two groups. For instance, if everyone stays in the control group but half the people in the experimental group resign from the study, the groups are no longer comparable. And finally, selection-maturation interaction is the possibility that people selected for the two groups have different maturation experiences. For instance, if the control group had normally sized people but the experimental group were composed of people with dietary issues, the second group might get hungrier and react differently in the experiment. What all of these internal validity threats have in common is that each one of them points to a different causal explanation of why the two groups might have had different results in the study. Random assignment, perfectly executed, should protect against all of these threats. That is why the “gold standard” for medical research designs requires random assignment (and also that both participants and experimenters are blind to each person’s assignment to one or the other group).

Assuming that these internal validity threats can be argumentatively nullified (or measured and accounted for), then we move to the question of external validity: “Given that we understand what happened within the study, can we be confident that it will also happen out in the real world?” In other words, external validity is concerned with the extent to which a study result can be generalized to a different population, a different context, and a different time. The issues here are reactive testing, interaction of the manipulation and selection, reactivity of the experimental circumstances, and multiple-treatment interference. Reactive testing refers to the possibility that the actual testing makes the participants unrepresentative of the general population. For instance, if people in the study have to weigh themselves every morning, that might make them more focused on their weight than the general population. Interaction of the manipulation and selection is the possibility that the people selected for participation in the study react differently to the manipulation than the population would. For instance, if the study consisted of people who are allergic to the ordinary medicine for some condition, their reaction to the new drug might not generalize to people who aren’t allergic to the standard treatment. Reactive effects of the experimental circumstances is the chance that people act differently in the experiment than they would in ordinary life. For instance, if participants in a depression study were brought to a lab full of scientific equipment and were attended by considerate professional personnel, they might be so taken with their general treatment that they became more optimistic than they would ordinarily have been, and therefore reacted better to the drug or counseling than people in a non-experimental setting will. Finally, multiple-treatment interference happens when multiple treatments are used in the study. For instance, if people are first counseled and then given a drug, we could not be sure that the drug alone would have had the same effects. These external validity issues point to arguments that might justify setting aside the experiment’s results when trying to understand how the overall population would react to the manipulation.

These issues summarize what might well be most of a course in study design, but what little we have said here should illustrate the kind of critical thinking that can be done about a study announcing some new generalization about diet, medicines, counseling, exercise, sleep patterns, or the many other things that journalists and bloggers are now reporting. These issues are likely to have been explicitly addressed in the original research report if the experimenters themselves were worried about the issue. Most experimenters are happy to do this because it justifies someone funding them for the next study. Corporations, however, might like their drug studies or other products never to be questioned so that they can persuade people to request the product. Therefore it is well to pay attention to who did the study, where it was published, whether there were conflicts of interest, whether the results can be replicated, and perhaps to wonder how that study out of all the studies on the topic was put in a journalist’s hands to report on.

We do not mean to be encouraging cynicism about scientific experiments. Cynicism is when things are rejected out of hand (“All politicians lie all the time, so ignore anything Senator Smith says”). Skepticism, which we do encourage, is withholding judgment until the evidence and arguments have been carefully examined.

As with surveys, people can do little approximate experiments themselves. You can set out a piece of fruit and a piece of pie to see which one your nephew will take first. You can make hints for your boyfriend to see how he will react. You can organize a group of fellow students to laugh at an instructor’s jokes only when she or he is looking at the ceiling. In each of these cases, you will have done a manipulation but you will be implicitly comparing your results to what you would have expected based on your experience, you will have a tiny sample size, you will not have a randomly assigned control group, and you will have taken many other huge shortcuts that would not be allowed in a real experiment. This doesn’t mean that your results are useless, but you should have great reserve about trusting or generalizing them too far.

5. Meta-analyses

In the early 1970s, one of us was taught in graduate school that “One study never proves anything.” By itself, this is an over-generalization. But as a guiding principle for reading individual studies it is a good impulse because it encourages reserve and proper skepticism. When evidence cumulates over many studies, generalizations from that data become increasingly reliable.

A meta-analysis is an “analysis of analyses.” A standard survey or experiment gets its data from individual respondents. A meta-analysis gathers its data from the results of previous surveys or experiments. The outcomes of those studies are averaged and analyzed to produce conclusions that are based on many studies and large groups of respondents.

Meta-analyses became increasingly common in the last quarter of the 20 th century. At first they were mainly offered as summaries of large research traditions and their merit was that they damped out the effects of occasional statistical flukes. But in the 21 st century additional analytic methods have been developed to critique whole lines of research. We have recently become aware of “replication crises” in medical and psychological research. The problem is that certain results don’t replicate—that is, that they can’t be reproduced by studies that had a good chance to generate the original findings. The new techniques can detect if failed research has been withheld from the public record, so that only the glittery results-revealing studies are published. The likelihood of missing studies can now be detected by examining the patterns of studies that do make it into print. If—and this is sadly not rare—the meta-analysis discovers that the big effects are reported with small-sample studies and that large-sample studies show lesser (or no) effects, the meta-analysis will now show this clearly. In other words, statistical scrutiny of the research record can now predict pretty well whether results will replicate or not. The techniques for doing this are complex and the scientific community is still in the process of choosing which ones deserve to be standard.

Meta-analyses are not yet reported in the media as commonly as dramatic single studies, but we can hope that this will change. A good meta-analysis is more trustworthy than a good survey or experiment. You can even do informal meta-analyses yourself. Perhaps you notice that most of your friends believe in some generalization, and then take on that generalization yourself. Although this can be an instance of the bandwagon fallacy, it may also be more reliable than trusting only your own impressions, especially if you have some reason to respect the views of the people who are influencing you.

6. Summary about Generalization-establishing arguments

And that brings us to a key point about generalizations generated by arguments, whether the argument takes the form of a survey, an experiment, a meta-analysis, or some less disciplined real-life activity (such as noticing a couple of examples of something or feeding your dog weird food for a day). Unless your reasoning was just irredeemably ridiculous, the generalization you came to should have some argumentative value. The question is how much. Generalizations, like other conclusions, need to be qualified so that they fit the strength of their argumentative support. A generalization can be “maybe true,” “occasionally true,” “possible, at least for people with histories of psychiatric upset,” “often true for men in Western cultures,” or something along those lines. The worst reasoning about generalizations happens when people let the generalization get loose from the argument that produced it. The best thing you can do when thinking in general terms is to keep in mind the nature of the generalization’s support and the inevitable flaws in those underlying arguments. Weigh the flaws properly and carry that weighing forward to the generalization.

So what about stereotypes? The nasty ones—remember, we are only claiming “to know them when we see them”—are based on terrible arguments. Often the evidence is biased. Perhaps you notice and remember every flaw in a postmodernist philosopher’s life but ignore or forget the very same flaws in a logician’s life. Or maybe there was no evidence at all. Perhaps your mother warned you against postmodernists before you set off for college, and you completely absorbed her warning that they are all pernicious, immoral youth-corrupters, without exception. Or perhaps you swallowed an unqualified generalization from your news feed without inquiring about the evidence that generated it. No one can investigate the basis for every opinion they hold—life is too short for that—but we are each responsible for what we believe and say. If you expose your generalizations to a good sample of the rest of the world, the world will let you know which of your opinions might actually be stereotypes, and those are the ones you need to investigate further. That is the nice thing about living in a civilly argumentative environment, rather than being completely self-enclosed or restricted to only like-minded familiars.

7. Generalization-using and Generalization-saturated arguments

To this point, we have been mainly considering arguments that conclude in a generalization. However, generalizations can appear elsewhere in an argument. An argument can use a generalization in its premises: Politicians say false self-serving things all the time; Prime Minister Cobbler says he is innocent of taking bribes; so Prime Minister Cobbler is lying. An argument can also be completely saturated with generalizations: Professors are all brilliant; brilliant people are all excellent friends; so professors all make excellent friends.

As far as we can tell, generalization-using and generalization-saturated arguments can take just about any form. They can be deductive, or causal, or practical, or many other things. Each of these other things is an argumentation scheme of its own. Every known argumentation scheme has its own form and its own associated critical questions. Douglas Walton, Chris Reed, and Fabrizio Macagno have written a book that details dozens of these schemes and lists their individual critical questions. All those critical questions, along with those you might generate if you were looking at an argument that didn’t quite fit their typology, come down to the ARSD standards, one way or the other.

Our message about such arguments has to do with A, the acceptability standard. Every premise that expresses a generalization ought to have been established by some prior argument. Perhaps it is based on scientific methods such as those we have discussed. More probably, it is based on some informal approximation of those scientific forms of reasoning: intuition, impressions, life experience, something you tried once with success, and so forth. Scientific method and statistics are basically just codifications of the best and most reliable kinds of informal reasoning. After investigation of a generalization, you should be able to connect its basis to what the best possible standards for the argument that established that generalization ought to have been.

A flaw in an argument’s premises interrupts the argument’s movement toward its conclusion. However, “flaw” is a matter of degree. A premise would have to be astonishingly awful to have no value at all. Just as we have tried to show you how to weigh and qualify the generalized conclusions to arguments, you should be able to apply that advice to the premises of other arguments. If you encounter a generalization-using or saturated argument that contains generalizations that are unqualified, all or nothing, black or white, you should try to figure out what the qualification should have been. That qualification should propagate throughout the argument, so that a qualification attached to a premise should reappear somehow in the conclusion. An exaggeration in the premises should be edited so that the conclusion isn’t exaggerated as well.

8. Conclusions

Generalizations are an inevitable and useful element of human thought and argument. It simply isn’t possible to store every individual bit of data in our heads or list them all in an argument. Even if it were possible it would be boring and overwhelming. We need generalizations. By summing things up, generalizations allow us to estimate what is likely to happen, to appreciate what might be going on now, and to understand what occurred before.

Like other kinds of thought and expression, generalizations can be imperfect. We can have over-generalizations that lack proper qualifying, we can have under-generalizations that don’t take proper account of important evidence, and we can have generalizations that are so poorly founded that they might as well be fictional. The essential way to evaluate and correct a generalization is to know where it came from, and to be able to evaluate its origins. Knowing the evidence for or against a generalization and the means that were used to generate that evidence, are essential to improving our own thought and our public discourse. The standards of acceptability, relevance, sufficiency, and dialectical quality can all be complex and challenging to apply, but they are essential in one form or another if we are to make and receive arguments as best we can.

Suggested Readings

Blair, J. A., & Johnson, R. H. (Eds.) (1980). Informal logic: The first inte r national symposium . Inverness CA: EdgePress.

Campbell, D. T., & Stanley, J. C. (1966). Experimental and quasi-experimental designs for research . Chicago: Rand McNally.

Cooper, H., Hedges, L. V., & Valentine, J. C. (Eds.) (2009). The handbook of research synthesis and meta-analysis (2d. ed.). New York: Sage.

Johnson, R. H. (2000). Manifest rationality: A pragmatic theory of arg u ment . Mahwah NJ: Erlbaum.

Walton, D., Reed, C., & Macagno, F. (2008). Argumentation schemes . Cambridge: Cambridge University Press.

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Critical Thinking: Investigating Arguments

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