Fallacies
The straight road on which sound reasoning proceeds gives little latitude for cruising about. I
ationality, carelessness, passionate attachment to one’s unexamined beliefs, and the sheer complexity of some issues occasionally spoil the reasoning of even the best of us. Although in this book we reprint many varied voices and arguments, we hope we’ve reprinted no readings that exhibit the most flagrant e
ors or commit the graver abuses against the canons of good reasoning. Nevertheless, an inventory of those abuses and their close examination can be an instructive (as well as an amusing) exercise — instructive because the diagnosis and repair of e
or help to fix more clearly the principles of sound reasoning on which such remedial labors depend; amusing because we are so constituted that our perception of the nonsense of others can stimulate our minds, warm our hearts, and give us comforting feelings of superiority.
The discussion that follows, then, is a quick tour through the twisting lanes, mudflats, forests, and quicksands of the faults that one sometimes encounters in reading arguments that stray from the highway of clear thinking.
FALLACIES OF AMBIGUITY
Ambiguity Near the center of the town of Concord, Massachusetts, is an empty field with a sign reading “Old Calf Pasture.” Hmm. A pasture in former times in which calves grazed? A pasture now in use for old calves? An erstwhile pasture for old calves? These alternative readings arise because of ambiguity;
evity in the sign has produced a group of words that give rise to more than one possible interpretation, confusing the reader and (presumably) frustrating the sign writer’s intentions.
Consider a more complex example. Suppose someone asserts People have equal rights and also Everyone has a right to property. Many people believe both these claims, but their combination involves an ambiguity. According to one interpretation, the two claims entail that everyone has an equal right to property. (That is, you and I each have an equal right to whatever property we have.) But the two claims can also be interpreted to mean that everyone has a right to equal property. (That is, whatever property you have a right to, I have a right to the same, or at least equivalent, property.) The latter interpretation is revolutionary, whereas the former is not. Arguments over equal rights often involve this ambiguity.
Division In the Bible, we read that the apostles of Jesus were twelve and that Matthew was an apostle. Does it follow that Matthew was twelve years old? No. To argue in this way from a property of a group to a property of a member of that group is to commit the fallacy of division.The example of the apostles may not be a very tempting instance of this e
or; here is a classic version that is a bit more interesting: If it is true that the average American family has 1.8 children, does it follow that your
other and sister-in-law are likely to have 1.8 children? If you think it does, you have committed the fallacy of division.
Composition Could an all-star team of professional basketball players beat the Boston Celtics in their heyday — say, the team of 1985–1986? Perhaps in one game or two, but probably not in seven out of a dozen games in a row. As students of the game know, teamwork is an indispensable part of outstanding performance, and the 1985–1986 Celtics were famous for their self-sacrificing style of play.
The fallacy of composition can be convincingly illustrated, therefore, in this argument: A team of five NBA all-stars is the best team in basketball if each of the five players is the best at his position. The fallacy is called composition because the reasoning commits the e
or of arguing from the true premise that each member of a group has a certain property to the not necessarily true conclusion that the group (the composition) itself has the property. (That is, because A is the best player at forward, Bis the best center, and so on, therefore, the team of A, B, … is the best team.)
Equivocation In a delightful passage in Lewis Ca
oll’s Through the Looking-Glass, the king asks his messenger, “Who did you pass on the road?” and the messenger replies, “Nobody.” This prompts the king to observe, “Of course, Nobody walks slower than you,” provoking the messenger’s sullen response: “I do my best. I’m sure nobody walks much faster than I do.” At this the king remarks with surprise, “He can’t do that or else he’d have been here first!” (This, by the way, is the classic predecessor of the famous comic dialogue “Who’s on First?” between the comedians Bud A
ott and Lou Costello.) The king and the messenger are equivocating on the term nobody. The messenger uses it in the normal way as an indefinite pronoun equivalent to “not anyone.” But the king uses the word as though it were a proper noun, Nobody, the rather odd name of some person. No wonder the king and the messenger talk right past each other.
Equivocation (from the Latin for “equal voice” — i.e., giving utterance to two meanings at the same time in one word or phrase) can ruin otherwise good reasoning, as in this example: Euthanasia is a good death; one dies a good death when one dies peacefully in old age; therefore, euthanasia is dying peacefully in old age. The etymology of euthanasia is literally “a good death,” so the first premise is true. And the second premise is certainly plausible. But the conclusion of this syllogism is false. Euthanasia cannot be defined as a peaceful death in one’s old age, for two reasons. First, euthanasia requires the intervention of another person who kills someone (or lets the person die); second, even a very young person can be euthanized. The problem arises because “a good death” works in the second premise in a manner that does not apply to euthanasia. Both meanings of “a good death” are legitimate, but when used together, they constitute an equivocation that spoils the argument.
The fallacy of equivocation takes us from the discussion of confusions in individual claims or grounds to the more troublesome fallacies that infect the linkages between the claims we make and the grounds (or reasons) for them. These are the fallacies that occur in statements that, following the vocabulary of the Toulmin method, are called the wa
ant of reasoning. Each fallacy is an example of reasoning that involves a non sequitur (Latin for “It does not follow”). That is, the claim (the conclusion) does not follow from the grounds (the premises).
For a start, here is an obvious non sequitur: “He went to the movies on three consecutive nights, so he must love movies.” Why doesn’t the claim (“He must love movies”) follow from the grounds (“He went to the movies on three consecutive nights”)? Perhaps the person was just fulfilling an assignment in a film course (maybe he even hated movies so much that he had postponed three assignments to see films and now had to see them all in quick succession), or maybe he went with a girlfriend who was a movie buff, or maybe … — well, there are any number of other possible reasons.
Questions Exercise: Fallacies — or Not?
Here, for diversion and practice, are some fallacies in action. Some of these statements, however, are not fallacies. Can you tell which is which? Can you detect what has gone wrong in the cases where something has gone wrong? Please explain your reasoning.
1. Abortion is murder — and it doesn’t matter whether we’re talking about killing a human em
yo or a human fetus.
2. Euthanasia is not a good thing, it’s murder — and it doesn’t matter how painful one’s dying may be.
3. Never loan a tool to a friend. I did once and never got it back.
4. If the neighbors don’t like our loud music, that’s just too bad. After all, we have a right to listen to the music we like when and where we want to play it.
5. The Good Samaritan in the Bible was pretty foolish; he was taking grave risks with no benefits for him in sight.
6. “Shoot first and ask questions afterward” is a good epigram for the kind of foreign policy we need.
7. “You can fool some of the people all of the time, and you can fool all the people some of the time, but you can’t fool all the people all of the time.” That’s what A
aham Lincoln said, and he was right.
8. It doesn’t matter whether Shakespeare wrote the plays attributed to him. What matters is whether the plays are any good.
9. The Golden Gate Bridge in San Francisco ought to be closed down. After all, just look at all the suicides that have occu
ed there.
10. Reparations for African Americans are way overdue; it’s just another version of the reparations eventually paid to the Japanese Americans who were wrongly interned in 1942 during World War II.
11. Animals don’t have rights any more than do trees or stones. They don’t have desires, either. What they have are feelings and needs.
12. The average American family is said to have 2.1 children. This is absurd — did you ever meet 2.1 children?
13. My ma
iage was a failure, which just proves my point: Don’t ever get ma
ied in the first place.
14. The Red Queen in Alice in Wonderland was right: Verdict first, evidence later.
15. Not until astronauts sailed through space around the moon and could see its back side for themselves did we have adequate reason to believe that the moon even had a back side.
16. If you start out with a bottle of beer a day and then go on to a glass or two of wine on the weekends, you’re well on your way to becoming a hopeless drunk.
17. Two Indians are sitting on a fence. The small Indian is the son of the big Indian, but the big Indian is not the small Indian’s father. How is that possible?
18. If you toss a coin five times and each time it comes up heads, is it more likely than not that on the sixth throw you’ll come up heads again — or is it more likely that you’ll come up tails? Or is neither more likely?
19. Going to church on a regular basis is bad for your health. Instead of sitting in a pew for an hour each Sunday, you’d be better off taking an hour’s
isk walk.
20. You can’t trust anything he says. When he was young, he was an avid Communist.
21. Since 9/11 we’ve tried and convicted few te
orists, so our defense systems must be working.
22. We can trust the White House in its press releases because it’s a reliable source of information.
23. Intelligent design must be true because the theory of evolution can’t explain how life began.
24. Andreas Se
ano’s notorious photograph called Piss Christ (1989), showing a small plastic crucifix submerged in a glass of urine, never should have been put on