“Ad hominem” is Latin for “against the man”. The ad hominem fallacy is the fallacy of attacking the person offering an argument rather than the argument itself.

Ad hominems can simply take the form of abuse: e.g. “don’t listen to him, he’s a jerk”. Any attack on irrelevant biographical details of the arguer rather than on his argument counts as an ad hominem, however: e.g. “that article must be rubbish as it wasn’t published in a peer-reveiwed journal”; “his claim must be false as he has no relevant expertise”; “he says that we should get more exercise but he could stand to lose a few pounds himself”.

Links