Critical thinking is reasonable and reflective thinking aimed at deciding what to believe or what to do. It is reflective in part because it requires us to think about our reasons as reasons, and so to ask whether they are acceptable and sufficient. It is reasonable in part because it requires us to look for reasons for our decisions. Throughout this book we have identified strategies and tricks that can help us to be more reflective and reasonable in our thinking. Here are some of them, organized into different categories.
The rule of Threes. The rule of threes has such broad application that it is difficult to state simply. Here are some applications of it. Find three alternative courses of action when trying to decide what to do. Look for three objections to a view you are defending. Think about a problem from three different perspectives before trying to solve it. Look for three examples when trying to define a concept. Looking for three—or, even better, five!—will help you become more reflective in your thinking by forcing you to think “outside the box.” Usually, finding one or two of the things you are looking for is relatively easy; trying to find more may force you to think harder, which is almost always good.
Do Not Personalize Reasons. Reasons and evidence do not belong to anyone; they are universal. And whether they are good has nothing to do with who accepts them; they are objective. To avoid personalizing reasons, replace the following:
with the following impersonal ones:
Think Twice; Decide Once. To paraphrase the old carpenter's motto (measure twice and cut once), it is best to think twice and decide once. We know from psychological experiments that people are reluctant to change their minds. Once our opinions are set, it seems to take a lot of doing to revise them. For one thing, people tend to privilege evidence that confirms their already existing beliefs over evidence that conflicts with it. They assume that evidence that conflicts with what they already believe is probably not reliable. For another thing, people tend to prefer the evidence they have to evidence they would have to do something to get. To protect against these built-in obstacles to critical thinking, it is better to make sure that one has enough of the right kind of evidence before one makes a decision. It is better to think twice and decide once, than to have to go back and revise one's own decisions.
Withhold Disagreement and Agreement. We all know what it feels like to explain our opinions and views to people we know disagree with us. It puts additional pressure on us, pressure that is not really helpful if the goal is to get clear on the truth of the matter. For this reason, it is best to withhold disagreement until the speaker has had a full opportunity to explain, defend, and support her view. If she feels rushed into explaining it, she might leave out some crucial distinctions, and this might have the effect of weakening what might in fact be a fairly plausible position. Or she might skip over some of the premises or fail to mention a response to an objection. Your goal as a critical thinker in a discussion is to help the other people make a case for their views that is as clear, as strong, and as complete as possible.
Keep Emotional Distance. Being a critical thinker means that our beliefs should be based on epistemic reasons, and not on emotional or pragmatic ones. Basing one's beliefs on emotions rather than on epistemic reasons is a mistake, since how a claim or proposal makes one feel emotionally is not a reliable guide to whether the claim is true or the proposal is good. Emotions can also make it difficult to collect the evidence we need, or even from investigating further. Emotions get in the way when we identify too much with our own opinions and beliefs or with our own methods for collecting or evaluating evidence. If I become too emotionally attached to my beliefs and opinions, then I may react negatively when someone asks me for my reasons, or when they raise objections to my belief, or when they state their own alternative beliefs. I might feel that they are criticizing me and not just my beliefs. The same is true if I am asked to defend my assessment of the evidence or my use of different methods for collecting evidence. If I come to identify too closely with these particular methods for assessing and collecting evidence, if I come to think of my value as a researcher as tied into their value, then I will react to criticisms of them as if they were criticisms of me and my judgment. This feeling of being under attack might make me feel defensive, and this can prevent me from thinking critically about the issue at hand. The same is true when I ask someone for his or her reasons. This sort of question is easily taken as aggressive or combative, even when the intention is simply to consider the issue from all sides as thoroughly as possible.
Trust, But (Be Prepared to) Verify. Most critical thinking theorists agree that it would be asking too much to require that before the evidence from some source can be accepted we must first know that the source is reliable. Instead, they recommend the following: evidence from some source is acceptable; unless one has reason to think the source is not reliable. Trusting our sources is a default right, as it were. But we should not let ourselves get carried away. For we know that some apparent sources are not reliable at all, and others even ones that are reliable can still yield mistaken evidence. To borrow Ronald Reagan's remark about the proper attitude to take to enemy superpowers: trust, but be prepared to verify.
Testing for Conceptual Independence. It is good to know how to test for conceptual independence. In Chapter 1, we considered Robert Ennis' definition of critical thinking as reasonable, reflective thinking aimed at deciding what to believe or what to. We also considered the standard philosophical definition of knowledge as justified, true belief. When an idea or concept is analyzed into several parts or elements, it is always a good idea to ask whether those parts or elements are conceptually independent of one another. To do this, simply ask yourself whether you can think of an example of something that has some of the elements but not others. For instance, we noticed that simple arithmetical calculations are a kind of thinking aimed at deciding what to believe but are not reflective because they do not require thinking about the method one uses. This example shows that being reflective thinking and being thinking that is aimed at deciding what to believe or do are conceptually independent. In one of the chapter's exercises, you discovered that in the case of knowledge, a belief's being true is conceptually independent of its being justified. Whenever a concept or problem has elements or parts, ask: how are those parts related to one another?
Look for Counterexamples. Looking for counterexamples is an important step in constructing or evaluating a proposed definition or in assessing the truth of a conditional. A counterexample is a case that shows that the definition is either too broad (includes things that it should not) or too narrow (excludes things that it should include). The case could be an actual one, or it could simply be a fictional one. If you think that a proposed definition is too broad or too narrow, then you need to present a counterexample and argue that it shows that the proposed definition is mistaken. If, on the other hand, you respond to an alleged counterexample to your proposed definition, then you have to either show that it is not a genuine counterexample to the definition or else revise the definition to include or exclude examples of that kind.
SEEC Definition Method. A definition should state the meaning as clearly as possible and in as short a sentence as possible. This statement can usually take the form of a slogan. A definition should expand on that statement by filling in some of the detail that inevitably will get left out of a succinct statement. Among other things, the elaboration might say something about how the different elements in the statement are related one to another. This should take no more than a few sentences. A definition should provide an example or two, depending on the complexity of what is being defined. The example could be from real life or it could be fictional, so long as it is clear and uncontroversial. Finally, a definition should identify some contrasting cases with which the thing being defined might easily be confused.
Ask open-ended Clarification Questions. When discussing topics with other people, ask them open-ended questions, not questions that allow an “Yes” or “No” answer. This will reduce the risk that superficial agreement will mask interesting and deep differences. Instead of asking:
Ask:
Be Charitable. When reconstructing someone's reasons, it is best to try to turn it into a valid argument. This may require adding a missing premise. The reason to reconstruct arguments so that they are valid is that this focuses the discussion on whether the premises (including the ones that you added) are true, as opposed to the question of whether the premises are sufficient. As we know, adding a premise can make any argument valid. But this alone will not make an argument a good one: its premises must be true or acceptable as well.
The Assertion Test. The premises in an argument are always assertions. But it is not always easy to tell in a passage or text just what the assertions are. To tell whether some proposition is asserted in a sentence of some text, ask whether the sentence as a whole could be true even if that proposition were false.
Identifying Dependent Reasons. It is important when analyzing a piece of reasoning to know whether the premises are working together (i.e., dependently) or whether they provide independent reason to accept the conclusion. There are two very useful strategies for deciding when the premises in an argument are dependent.
One is the Words Test: If the conclusion of an argument contains important words that occur only in one premise and important words that occur only in another premise, then those premises are probably dependent.
Another is the False Premise Test: If a premise would provide some reason to accept the conclusion even if another premise were false, then those premises are independent. So, to test whether premises are dependent, suppose that one is false, and ask whether the other one would still provide some support for the conclusion. If it would, then the premises are independent. If not, then they are dependent.
Testing for Logical Strength. To test the logical strength of an argument, suppose that the premises were true. Then ask: how likely is that the conclusion would be true too? The higher the likelihood, the more logical support the premises provide.