But their other propositions they defend by numerous and varied arguments, and they likewise are two in number. One is—“Of those things which appear, some are true and others false;” the other is—“Every perception which originates in the truth, is of such a character as it might be of, though originating in what is false.” And these two propositions they do not pass by, but they expand in such a manner as to show no slight degree of care and diligence. For they divide them into parts, and those also large parts; first of all into the senses, then into those things which are derived from the senses, and from universal custom, the authority of which they wish to invalidate. Then they come to the point of laying it down that nothing can be perceived even by reason and conjecture. And these universal propositions they cut up into more minute parts. For as in our yesterday’s discussion you saw that they acted with respect to the senses, so do they also act with respect to everything else. And in each separate thing which they divide into the most minute parts, they wish to make out that all these true perceptions have often false ones added to them, which are in no respect different from the true ones; and that, as they are of such a character, nothing can be comprehended. 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.