Assume that your opponent is wrong, and explain his error, and the world will be at your feet.

You must show that a man is wrong before you start explaining why he is wrong. The modern method is to assume without discussion that he is wrong and then distract his attention from this (the only real issue) by busily explaining how he became so silly.

In the course of the last fifteen years I have found this vice so common that I have had to invent a name for it. I call it “Bulverism”. Some day I am going to write the biography of its imaginary inventor, Ezekiel Bulver, whose destiny was determined at the age of five when he heard his mother say to his father—who had been maintaining that two sides of a triangle were together greater than a third—”Oh you say that because you are a man.” “At that moment”, E. Bulver assures us, “there flashed across my opening mind the great truth that refutation is no necessary part of argument. Assume that your opponent is wrong, and explain his error, and the world will be at your feet. Attempt to prove that he is wrong or (worse still) try to find out whether he is wrong or right, and the national dynamism of our age will thrust you to the wall.” That is how Bulver became one of the makers of the Twentieth Century.

– from “Undeceptions”, by C.S. Lewis

Last Friday, my coworker reads a news announcement about Netflix claiming that they will be pushing back against sharing passwords. However, they don’t say how they would do it. My co-worker openly speculates that they might be bluffing. While this is a pure speculation on her part, the response catches my attention. Another coworker immediately says she is “projecting” because she doesn’t have a Netflix account.

In other words, since my coworker has no Netflix account, my other coworker assumes that my first coworker is wrong, and proceeds to say why she is wrong on the basis of my co-worker’s personal preference.

This all being said, I will admit that in this context the response is possibly meant in good humor. However, this logical fallacy is commonly used in contexts that are no laughing matter.

Bulverism is a variation of Ad Hominem, which dismisses arguments by discriminating on basis of the person making the argument. Ad Hominem tends to focus on who the person is (or was), Bulverism focuses on an attribute of the person.

Bulverism is often spotted when someone says something like “you just say that because you…”

A known political example is to say that men can’t have or voice an opinion on abortion. It presupposes the opinion to be already wrong (or wrong to express) on basis of sex.

The best way to avoid Bulverism is to consider the argument on its own merits, even if the person giving the argument is someone you dislike or disagree with.