Contradiction and contention irritate a man into exaggerating his statement. By contradicting your opponent you may drive him into extending beyond its proper limits a statement which, at all events within those limits and in itself, is true; and when you refute this exaggerated form of it, you look as though you had also refuted his original statement. Contrarily, you must take care not to allow yourself to be misled by contradictions into exaggerating or extending a statement of your own. It will often happen that your opponent will himself directly try to extend your statement further than you meant it; here you must at once stop him, and bring him back to the limits which you set up; “That’s what I said, and no more.”
This trick consists in stating a false syllogism. Your opponent makes a proposition, and by false inference and distortion of his ideas you force from it other propositions which it does not contain and he does not in the least mean; nay, which are absurd or dangerous. It then looks as if his proposition gave rise to others which are inconsistent either with themselves or with some acknowledged truth, and so it appears to be indirectly refuted. This is the diversion, and it is another application of the fallacy non causae ut causae.
This is a case of the diversion by means of an instance to the contrary. With an induction ([Greek: epagogae]), a great number of particular instances are required in order to establish it as a universal proposition; but with the diversion ([Greek: apagogae]) a single instance, to which the proposition does not apply, is all that is necessary to overthrow it. This is a controversial method known as the instance—instantia, [Greek: enstasis]. For example, “all ruminants are horned” is a proposition which may be upset by the single instance of the camel. The instance is a case in which a universal truth is sought to be applied, and something is inserted in the fundamental definition of it which is not universally true, and by which it is upset. But there is room for mistake; and when this trick is employed by your opponent, you must observe (1) whether the example which he gives is really true; for there are problems of which the only true solution is that the case in point is not true—for example, many miracles, ghost stories, and so on; and (2) whether it really comes under the conception of the truth thus stated; for it may only appear to do so, and the matter is one to be settled by precise distinctions; and (3) whether it is really inconsistent with this conception; for this again may be only an apparent inconsistency.
A brilliant move is the retorsio argumenti, or turning of the tables, by which your opponent’s argument is turned against himself. He declares, for instance, “So-and-so is a child, you must make allowance for him.” You retort, “Just because he is a child, I must correct him; otherwise he will persist in his bad habits.”