The Science of Conjecture: Evidence and Probability Before Pascal

by James Franklin

The argument about the young man is a clearer example than anything in Aristotle of the proportional syllogism, that is, the argument from a proportion in a reference class to a particular case: Young men generally act thus, so this particular young man probably acts thus. The author helpfully adds something on how to reply to such arguments. “If you have never done anything of the kind, but some of your friends do happen to have done such things, you must say that it is not just that you should be discredited because of them, and must show that others of your associates are honest men; you will thus throw doubt on the accusation. If they show that other people who resemble you have done the same things, declare it to be absurd if the fact that certain others can be shown to have done wrong is to be a proof that you too have committed the offences alleged against you. That is how you must make your defence from likelihood (eikoton) if you are denying that you have done the thing alleged, because this will make the charge improbable (apithanon).”