Where an argument comes from is not supposed to be relevant to the logical credibility of the argument, and there are named fallacies that highlight just such errors. (I’m going to talk loosely here, at first, so take the immediately following with a grain of salt.) The genetic fallacy says that where an argument comes from – its origins or “genesis” – should not be treated as relevant to the cogency of that argument. A somewhat more specific version of the genetic fallacy is a variant on the argumentum ad hominem, known as the tu quoque fallacy. “Tu quoque” basically means “you too,” or “you’re another.” The idea with this latter is rejecting the advice or argument of a person on the grounds that that person is doing the very thing she or he is advising against.
However, such a rejection is clearly not only unfair, but unjustifiable. An alcoholic may not be able to stop drinking, but is certainly in a position to understand the evils of that drinking, and present cogent arguments against it. Similarly, the nicotine addict, slowly suffocating from emphysema may not be physically or psychologically able to stop smoking, but said person is certainly well placed to understand the viciousness of doing so, and can offer extremely valid arguments against ever picking up the habit. But there are times when the source of a claim really is important, and needs to be taken into account when evaluating a claim. The probative value of evidence which we are not able to check ourselves often rests on the credibility of the source. The superficial version of the genetic fallacy that I presented above says that the source of a claim should not be given any weight, and that the argument should be evaluated by itself and on its own terms. But when we do not have complete control and/or mastery over those terms, then that source must also be taken into account. Continue reading