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Nominal Fallacy

Not everything that sounds like an explanation is a useful one. Some explanations are really examples of the nominal fallacy (nominal ~ naming; fallacy ~error). I will call it the naming-explaining fallacy, because that's easier to remember. You commit the naming-explaining fallacy when you apply a label (or name) to something and think you have explained it.

For example, her friends say that Rachelle is an intelligent person to explain why she gets high grades without seeming to work very hard. How do they know Rachelle is an intelligent person? She gets high grades without seeming to work very hard. If her high grades provide the only reason they say Rachelle is intelligent, her friends are committing the naming-explaining fallacy: The label "intelligent" is based on the fact Rachelle gets high grades, which is exactly what the label is supposed to explain.

Now if her friends say Rachelle is intelligent because she has a large vocabulary, then saying she gets high grades because she is intelligent begins to be an explanation for the high grades. The label "intelligent" now adds something to what we know about Rachelle, besides the fact that she gets high grades. Her friends used something else than high grades to apply the label "intelligent" to Rachelle, so they add something to the fact they explain.

In the early part of the 20th century, some psychologists "explained" many behaviors by saying they were "instincts." If Reggie fought with others a lot, his fighting was "explained" by saying he had a strong aggressive instinct, based only on the fact that he fought a lot. Partly because of such misuse, instinct was more or less banned from the psychological vocabulary for at least a half century.


The Post Hoc Fallacy. A post hoc (after the fact) explanation is another "explanation" that isn't an explanation. Post hoc means that after something happens, you pull out an explanation which is based entirely on already knowing what happens. Something happens, and you pull out an explanation that fits, without any evidence that it's correct.

For example, Jane starts dating Joe, who is very much like her. Jane's friends "explain" this pairing by saying, "Birds of a feather flock together" or "People want to be with people like themselves." But the only evidence they have that this is Jane's motivation for dating Joe is the fact that she is dating him. But when Jane and Joe break up, and Jane starts dating Damien, who is very different, her friends "explain" this new pairing by saying "Opposites attract" or "She was looking for someone different after breaking up with Joe." Again, the only evidence they have that this is Jane's motivation for dating Damien is the fact that she is dating him. Another common example of a post hoc explanation is the kind stock market analysts give to explain why the market is up (or down) after it happens.