"A fallacy is an unsound or inconclusive argument; an argument supposed or alleged to prove a conclusion which it does not prove. The name is sometimes confined to sophisms, that is, unsound arguments used with the intention to deceive. But the intention is a point of secondary importance in the theory of fallacies; and, indeed, those fallacies in which the reasoner deceives himself are by far more dangerous than the others, because they are by far more common. The term Fallacy, it will thus be observed, is applicable to an argument taken as a whole, not to any of the propositions of which the argument is composed. The propositions severally must be true or false: the argument which they constitute must be correct or fallacious ; that is, its conclusion must either follow or not follow from the premises."