XIV. Now all this subtlety I consider indeed thoroughly worthy of philosophy, but still wholly unconnected with the case which they advocate who argue thus. For definitions, and divisions, and a discourse which employs these ornaments, and also similarities and dissimilarities, and the subtle and fine-drawn distinctions between them, belong to men who are confident that those arguments which they are upholding are true, and firm, and certain; and not to men who assert loudly that those things are no more true than false. For what would they do if, after they had defined anything, some one were to ask them whether that definition could be transferred to something else? If they said it could, then what reason could they give why it should be a true definition? If they said no,—then it must be confessed, since that definition of what is true cannot be transferred to what is false, that that which is explained by that definition can be perceived; which is the last thing they mean.
The same thing may be said on every article of the division. For if they say that they see clearly the things about which they are arguing, and they cannot be hindered by any similarity of appearance, then they will confess that they are able to comprehend those things. But if they affirm that true perceptions cannot be distinguished from false ones, how can they go any further? For the same objections will be made to them which have been made already; for an argument cannot be concluded, unless the premises which are taken to deduce the conclusion from are so established that nothing of the same kind can be false.
Therefore, if reason, relying on things comprehended and perceived, and advancing in reliance on them, establishes the point that nothing can be comprehended, what can be found which can be more inconsistent with itself? And as the very nature of an accurate discourse professes that it will develop something which is not apparent, and that, in order the more easily to succeed in its object, it will employ the senses and those things which are evident, what sort of discourse is that which is uttered by those men who insist upon it that everything has not so much an existence as a mere appearance?
But they are convicted most of all when they assume, as consistent with each other, these two propositions which are
