The Science of Conjecture: Evidence and Probability Before Pascal

by James Franklin

Aristotle explains the nature of such arguments and expresses the general disapproval later felt for the whole immoral business. “It is of this line of argument that Corax’s Art of Rhetoric is composed,” he says. “If the accused is not open to the charge, for instance if a weakling is being tried for assault, the defence is that he was not likely (eikos) to do such a thing. But if he is open to the charge—if he is a strong man— the defence is still that he was not likely to do such a thing, since he could be sure that people would think he was likely to do it. And so with any other charge: the accused must be either open or not open to it: there is in either case an appearance of likely innocence, but whereas in the latter case the likelihood is genuine, in the former it is only in the special sense mentioned. This sort of argument illustrates what is meant by making the worse argument seem the better. Hence people were right in objecting to the training Protagoras undertook to give them. It was a fraud; its likelihood was not genuine but an appearance, and has a place in no art except rhetoric and eristic.”