2 Aristotle 2 · On Arguing. Handed down at the Lyceum, from his Sophistical Refutations and his Ethics
This book does not set out the forms of inference, nor where starting points come from. Those belong in a school, not in a life. What is kept is the three things a person needs among other people: how to see whether you are after the truth or after the win, how to hear a bad argument, and how far a thing needs proving before you stop.
2.1Bad reasoning comes in a few shapes, and men are caught by them every year. I set down the common ones here.
2.2First, the shifted word: one word means one thing in the first sentence and another in the second.
2.3"Everything natural is good; sickness is natural; therefore sickness is good." — the word natural was changed on the way through.
2.4Second, the whole and the parts: what is true joined may not be true apart, and what is true apart may not be true joined.
2.5"Every man in this troop is able, therefore this troop will get the thing done." — not necessarily. Able men may not work together.
2.6Third, taking what is in dispute: the sentence to be proved is already hidden in the premises.
2.7"This man is not to be believed, because everything he says is false." — that is the very thing you were to prove.
2.8Fourth, the false cause: two things come one after the other, and the earlier is taken for the cause.
2.9The cock crows before sunrise. The cock has never crowed up the sun.
2.10Fifth, two questions as one: two questions are sewn together, so that answering either end concedes the other.
2.11"Have you stopped beating your father?" — yes concedes it, and no concedes it. When you meet one of these, take it apart first.
2.12Sixth, the man for the matter: instead of answering the sentence, one turns and talks about the man.
2.13A bad man may be right about a thing. A good man may be wrong about a thing.
2.14A sentence is a sentence and a man is a man. To refute the sentence you have to come back to the sentence.
2.15Seventh, the part taken for the whole: what is true in a certain respect is taken as true without qualification.
2.16"This medicine is good for a sick man, therefore medicine is a good thing." — good for that man, at that time.
2.17Whenever you meet a claim stated without qualification, ask first: under what conditions?
2.18Learn these seven by heart. Once you have them, half of all nonsense you will hear as it is spoken.
2.19The other half will be new tricks. There are new tricks every year, but taken apart, most of them are these seven in fresh clothes.