I just finished reading, Why Good Arguments Fail, by James W. Sire. I really enjoyed it. I was reminded how often I hear logical fallacies in everyday conversation. I even use them every once in a while. Sire offered some really clear examples of common fallacies and so I thought I’d share some of his info. Enjoy!
1) Exercise is good. Therefore everybody should exercise.[i]
2) You can’t speak German. I can’t speak German. Classmate Jim can’t speak German. I must therefore conclude that nobody at Gordon-Conwell Theological Seminary can speak German.[ii]
3) If God can do anything , he can make a stone so heavy he can’t lift it.[iii]
4) A man applies for a job. When the boss asks him what his qualifications are, he replies that he has a wife with 6 children, his wife is a helpless cripple, the children have nothing to eat, no clothes to wear, no shoes on their feet, no coal in the cellar and winter is coming. [iv]
5) Students should be allowed to look at textbooks during their tests. After all, surgeons have X rays to guide them during an operation. Lawyers have briefs to guide them during the trials, carpenters use blueprints when they build a house. So why can’t students use textbooks during their tests?[v]
6) If Madame Curie had not happened to leave a photographic plate in a drawer with a chunk of pitchblende, the world today would not know about radium.[vi]
7) Two men are having a debate. The first one gets up and says, “My opponent is a notorious liar. You can’t believe a word he is going to say.”[vii]
How did you do? I may follow up this post with examples that are more “spiritual.” Maybe ones Christians commonly hear and even (gasp) use.
[i] This is an argument based on an unqualified generalization. Formally named a Dicto Simpliciter. “Exercise is good” needs to be qualified. For example, if you have heart disease, exercise is bad, not good. Many people are ordered by their doctors NOT to exercise. It should be said, “exercise is usually good” or “exercise is good for most people.”
[ii] This is a fallacy because it is a hasty generalization. There are too few instances to sufficiently and reasonably prove the point.
[iii] Here, the premises of the argument contradict each other. Logicians would call this “Contradictory Premises.” When the premises of an argument contradict each other, there can be no argument.
[iv] Formally, an Ad Misericordiam. It isn’t an argument, the man never actually answered the boss’ question. He simply appealed to the boss’ sympathy (emotions).
[v] Here, the speaker is using False Analogy. Doctors, Lawyers and Carpenters aren’t taking a test to see how much they have learned, but students are. The situations are necessarily different. Thus it isn’t fair to make an analogy between them.
[vi] Maybe Madame Curie would have discovered radium at some later date. Maybe somebody else would have discovered it. Maybe any number of things would have happened. You can’t start with a hypothesis that is not true and then draw any supportable conclusions from it. This would be labeled, “Hypothesis Contrary to Fact.”
[vii] Here, the man is doing what is called, “Poisoning the Well.” It isn’t fair. He has poisoned the well before anyone could drink from it. He has hamstrung his opponent before his opponent could defend himself. Neither respectable nor respectful, don’t do it!