Causal Reasoning

　　Of the three types of inductive reasoning we will discuss， causal reasoning

　　is both the weakest and the most prone¹ to fallacy. Nevertheless， it is a us

　　eful and common method of thought.

　　To argue by causation is to claim that one thing causes another. A causal ar

　　gument can be either weak or strong depending on the context. For example， t

　　o claim that you won the lottery² because you saw a shooting star the night b

　　efore is clearly fallacious. However， most people believe that smoking cause

　　s cancer because cancer often strikes those with a history of cigarette use.

　　Although the connection between smoking and cancer is virtually certain， as

　　with all inductive arguments it can never be 100 percent certain. Cigarette

　　companies have claimed that there may be a genetic³ predisposition in some p

　　eople to both develop cancer and crave⁴ nicotine⁵. Although this claim is high

　　ly improbable， it is conceivable.

　　There are two common fallacies associated with causal reasoning：

　　1. Confusing Correlation⁶ with Causation.

　　To claim that A caused B merely because A occurred immediately before B is c

　　learly questionable⁷. It may be only coincidental that they occurred together

　　， or something else may have caused them to occur together. For example， the

　　fact that insomnia⁸ and lack of appetite often occur together does not mean

　　that one necessarily causes the other. They may both be symptoms of an under

　　lying condition.

　　2. Confusing Necessary Conditions with Sufficient Conditions.

　　A is necessary for B means “B cannot occur without A.” A is sufficient for B

　　means “A causes B to occur， but B can still occur without A.” For example，

　　a small tax base is sufficient to cause a budget deficit⁹， but excessive spen

　　ding can cause a deficit even with a large tax base. A common fallacy is to

　　assume that a necessary condition is sufficient to cause a situation. For ex

　　ample， to win a modern war it is necessary to have modern， high-tech¹⁰ equipme

　　nt， but it is not sufficient， as Iraq discovered in the Persian Gulf¹¹ War.

　　SEVEN COMMON FALLACIES

Contradiction

　　A Contradiction is committed when two opposing statements are simultaneously¹²

　　asserted. For example， saying “it is raining and it is not raining” is a co

　　ntradiction. Typically， however， the arguer obscures the contradiction to th

　　e point that the argument can be quite compelling. Take， for instance， the f

　　ollowing argument：

　　“We cannot know anything， because we intuitively realize that our thoughts a

　　re unreliable.“

　　This argument has an air of reasonableness to it. But “intuitively realize”

　　means “to know.” Thus the arguer is in essence saying that we know that we d

　　on't know anything. This is self-contradictory.

　　Equivocation¹³

　　Equivocation is the use of a word in more than one sense during an argument.

　　This technique is often used by politicians to leave themselves an “out.” I

　　f someone objects to a particular statement， the politician can simply claim

　　the other meaning.

　　Example：

　　Individual rights must be championed by the government. It is right for one

　　to believe in God. So government should promote the belief in God.

　　In this argument， right is used ambiguously. In the phrase “individual right

　　s“ it is used in the sense of a privilege， whereas in the second sentence ri

　　ght is used to mean proper or moral. The questionable conclusion is possible

　　only if the arguer is allowed to play with the meaning of the critical word

　　right.

　　Circular Reasoning

　　Circular reasoning involves assuming as a premise¹⁴ that which you are trying

　　to prove. Intuitively， it may seem that no one would fall for such an argume

　　nt. However， the conclusion may appear to state something additional， or the

　　argument may be so long that the reader may forget that the conclusion was

　　stated as a premise

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