To think clearly is thinking critically. All of us have the natural instincts to think critically but we seldom use it. Critical thinking examines the arguments by which we try to evaluate claims or settle issues. To initiate critical thinking we need to understand: its value, its purpose and its subject matter.

1. Critical thinking is the process of assessing opinions.

We all might be entitled to our opinions, but some opinions are more reasonable than others.
Critical thinking consists of examining the views that you and others hold and the reasons for them.
Its main purpose is not to make you either more persuasive or a better contestant against others, but to improve your ability to understand and evaluate what you believe.

2. Critical thinking is clear thinking about issues.

Clear thinking about an issue involves identifying the issue, recognizing what positions people are taking on that issue, and understanding the arguments for and against those positions.
1. All these steps can be quickly defined, but they cannot always be learned that quickly.
2. The ultimate goal of the entire process is a decision: What are the best reasons to accept a claim, reject it, or suspend judgment?
An issue is any point being discussed or thought about.
1. An issue may also be thought of as a question: Some assertion has to be decided on.
2. Issues can usually be stated so that they begin with “whether”: Whether you should buy this car, or whether you should buy any car at all.
3. A psychological problem or hang-up is commonly called an “issue”; not here.
4. Nor is an issue something as broad as a topic of conversation, for a topic does not always call for a question to be answered, and an issue does.
An argument is an attempt to support a claim by giving reasons for believing it.
1. The claim being argued for is the argument’s conclusion, while the claim or claims given as reasons for accepting the conclusion are premises.
2. Arguments are often confused with attempts to persuade.
  1. It is true that good arguments can persuade people. But not all arguments are made for the purpose of persuading, and without a doubt not all attempts to persuade are arguments.
  2. Talk about arguments and persuasion muddies the waters. Rather than worrying about whether an argument can make someone else believe what you say, focus on its purpose of proving or supporting a claim.
3. Another confusion comes when people think of arguments as explanations.
  1. This confusion is more honest but can still lead you into trouble. In later chapters the difference between arguments and explanations should become clear.
  2. Briefly, an argument tries to show that some sentence is true; an explanation tries to say why something happens or how it happens.
4. To identify an argument you need to identify its conclusion and its premises (or in some cases its single premise).
  1. Very often certain words or phrases, conclusion indicators, point to the coming conclusion: “therefore,” “hence,” “we may conclude,” and so on.
  2. Premise indicators likewise alert you to the appearance of a premise: “since,” “because,” “given that,” etc.
  3. These indicators are only a first clue to the parts of an argument; but though they are not always present, there are other techniques for spotting the parts of arguments.
  4. What complicates things even more is that an argument’s conclusion or one or more of its premises may never be stated explicitly.

3. The first step in thinking clearly about an issue is the identification of that issue.

In a conversation, a newspaper editorial, or a book, more than one issue might be under consideration; or the issue may go unstated; so it often takes work to identify the issue in question.
One method begins by spotting the argument being given.
1. Every argument addresses an issue.
2. So if you can find an argument’s conclusion, you can immediately identify at least one of the issues at stake: just put the word “whether” before the conclusion.
3. Bear in mind that more than one issue comes up in a conversation or piece of writing. Look for as many as you can and don’t worry too much about whether you have found them all.

4. The second step in thinking about an issue requires telling the difference between factual and nonfactual issues or questions.

Factual issues are about factual claims. A factual claim does not have to be true. But if it is true it states a fact.
1. “Beyond Pluto there is another planet” is a factual claim even if we never find out the truth of it.
2. “‘Eggplant’ is a funnier word than ‘broccoli’” is a nonfactual claim.
Before discussing an issue you need to tell if it is a factual one.
1. One method: if two people disagree and at least one of them has to be mistaken, the issue is factual. “Eggplant” may make you chuckle while “broccoli” amuses me much more deeply, but neither of us has to be wrong about anything.
2. Another method: If established methods exist for settling a question, it is a factual question. Astronomers have definitions of planets and know how to look for them; hence the question of a tenth planet is a factual one.
3. Even when methods exist for settling an issue, that issue might still be controversial: “factual” does not mean “uncontroversial.”
Sometimes this distinction leads to the belief that all opinions about nonfactual issues are equally good.
1. Remember that an argument tries to support one position on a given issue. One argument about a nonfactual matter may still be stronger or weaker than another one, more or less relevant, grounded on firmer or sketchier premises.
2. So even when the conversation turns to nonfactual issues it is vitally important to produce and evaluate arguments with the same care you devote to arguments about factual issues.
3. Questions of moral decisions and aesthetic judgments raise very important types of nonfactual issues. In discussions of those issues it is especially important to insist on good arguments. See Chapter 13 for more.
Sometimes however people ignore the distinction between factual and nonfactual issues, with grave and undesirable consequences.
1. Subjectivism is the view that two people can disagree about a factual issue and both of them still be “right.”
2. Relativism, a subjectivism about different cultures, claims that two cultures can disagree about a factual issue while, again, both of them are “right.”
3. Both of these doctrines are at best confused about what “right” means and what a factual issue is. Critical thinking is thinking that avoids falling into the pothole of subjectivism.

5. As a final preparation to clear thinking, watch out for the factors that might influence your decision about a claim but are in fact irrelevant to that decision.

Human beings are commonly influenced by considerations that strictly speaking do not have to do with the truth of a claim
1. We take friends’ and relatives’ opinions more seriously than those of strangers; we feel more like agreeing with people who present themselves attractively or speak well.
2. Likewise, a clumsy and shy delivery can make us reject what a speaker is saying.
3. Some words are more persuasive than others: two sentences may convey exactly the same claim, one of them in neutral terms and the other in vivid language.
Being influenced in these and similar ways is natural but needs to be watched out for.
1. The purpose of critical thinking is not to bleach all the emotion out of you; nor to make you ignore your family members’ opinions. (“I’m not going to pay any special attention to what you say, Grandpa, to me you are just one more person.”)
2. From the specific point of view of assessing arguments, however, such considerations need to be separated from considerations of the merits of arguments themselves.
3. Compare critical thinking to auto mechanics. A mechanic at work on a car ignores the color, shape, and design of the car, not out of insensitivity but because those features do not bear on how well the car runs or what might be wrong with it. Many mechanics are car lovers; as human beings they are fascinated by the looks of a car. As mechanics however they keep those irrelevant features separated from what they are doing. Likewise: As an emotional person you might find yourself very strongly moved by the language of a statement, or the circumstances of who made a certain claim; but as a critical thinker you set those matters aside and focus on what is relevant to the statement’s truth.