Do you agree with Clifford?
MORAL REASONING
’ You might be surprised to learn that some philoso- phers consider reasoning itself a moral issue. That is, they think that believing a claim without good reasons (an unsupported statement) is immoral. Probably the most famous exposition of this point comes from the philosopher and mathematician W. K. Clifford (1845–79). He has this to say on the subject:
It is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence. If a man, holding a belief which he was taught in childhood or persuaded of afterwards, keeps down and pushes away any doubts which arise about it in his mind . . . and regards as impious
those questions which cannot easily be asked without disturbing it—the life of that man is one long sin against mankind.*
Do you agree with Clifford? Can you think of a counterexample to his argument—that is, instances in which believing without evidence would be morally permissible? Suppose the power of reason is a gift from God to be used to help you live a good life. If so, would believing without evidence (failing to use critical thinking) be immoral?
*W. K. Clifford, “The Ethics of Belief,” in The Rationality of Belief in God, ed. George I. Mavrodes (Englewood Cliffs, NJ: Prentice-Hall, 1970), 159–60.
CRITICAL THOUGHT: The Morality of Critical Thinking
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Now let us turn to inductive arguments. Exam- ine this one:
Almost all the men at this college have high SAT scores.
Therefore, Julio (a male student at the college) probably has high SAT scores.
This argument is inductive because it is intended to provide probable, not decisive, sup- port to the conclusion. That is, the argument is intended to show only that, at best, the conclu- sion is probably true. With any inductive argu- ment, it is possible for the premises to be true and the conclusion false. An inductive argument that manages to actually give probable support to the conclusion is said to be strong. In a strong argu- ment, if the premises are true, the conclusion is probably true (more likely to be true than not). The SAT argument is strong. An inductive argu- ment that does not give probable support to the conclusion is said to be weak. In a weak argu- ment, if the premises are true, the conclusion is not probable (not more likely to be true than not true). If we change the first premise in the SAT argument to “Twenty percent of the men at this college have high SAT scores,” the argument would be weak.
Like deductive arguments, inductive ones are often accompanied by indicator words. These terms include probably, likely, in all probability, it is reasonable to suppose that, odds are, and chances are.
Good arguments provide you with good reasons for believing their conclusions. You now know that good arguments must be valid or strong. But they must also have true premises. Good arguments must both have the right form (be valid or strong) and have reliable content (have true premises). Any argument that fails in either of these respects is a bad argument. A valid argument with true premises is said to be sound; a strong argument with true premises is said to be cogent.
To evaluate an argument is to determine whether it is good or not, and establishing that
requires you to check the argument’s form and the truth of its premises. You can check the truth of premises in many different ways. Sometimes you can see immediately that a premise is true (or false). At other times you may need to examine a premise more closely or even do some research. Assessing an argument’s form is also usually a very straightforward process. With inductive arguments, sometimes common sense is all that’s required to see whether they are strong or weak (whether the conclusions follow from the premises). With deductive arguments, just thinking about how the premises are related to the conclusion is often suf- ficient. In all cases the key to correctly and effi- ciently determining the validity or strength of arguments is practice.
Fortunately, there are some techniques that can improve your ability to check the validity of deductive arguments. Some deductive forms are so common that just being familiar with them can give you a big advantage. Let’s look at some of them.
To begin, understand that you can easily indi- cate an argument’s form by using a kind of standard shorthand, with letters standing for statements. Consider, for example, this argument:
If Maria walks to work, then she will be late.
She is walking to work.
Therefore, she will be late.
Here’s how we symbolize this argument’s form:
If p, then q.
p.
Therefore, q.
We represent each statement with a letter, thereby laying bare the argument’s skeletal form. The first premise is a compound statement, con- sisting of two constituent statements, p and q. This particular argument form is known as a condi- tional. A conditional argument has at least one conditional premise—a premise in an if-then pat- tern (If p, then q). The two parts of a conditional