Bulverism


Bulverism is a logical fallacy. The method of Bulverism is to "assume that your opponent is wrong, and explain his error." The Bulverist assumes a speaker's argument is invalid or false and then explains the speaker came to make that mistake, attacking the speaker or the speaker's motive. The term Bulverism was coined by C. S. Lewis to poke fun at a very serious error in thinking that, he alleges, recurs often in a variety of religious, political, and philosophical debates.
Similar to Antony Flew's "subject/motive shift", Bulverism is a fallacy of irrelevance. One accuses an argument of being wrong on the basis of the arguer's identity or motive, but these are strictly speaking irrelevant to the argument's validity or truth.

Threat and remedy

The special threat of this fallacy lies in that it applies equally to the person who errs as to that person's opponent. Taken to its logical consequence, it implies that all arguments are unreliable and hence undermines all rational thought. Lewis says, "Until Bulverism is crushed, reason can play no effective part in human affairs. Each side snatches it early as a weapon against the other; but between the two reason itself is discredited."
The remedy, according to Lewis, is to accept that some reasoning is not tainted by the reasoner. Some arguments are valid and some conclusions true, regardless of the identity and motives of the one who argues them.