And again, if it does not occur to a man’s mind what his duty is, he will actually never do anything, he will never be excited to any action, he will never be moved. But if he ever is about to do anything, then it is necessary that that which occurs to him must appear to him to be true. What! But if those things are true, is the whole of reason, which is, as it were, the light and illumination of life, put an end to? And still will you persist in that wrong-headedness? For it is reason which has brought men the beginning of inquiry, which has perfected virtue, after reason herself had been confirmed by inquiry. But inquiry is the desire of knowledge; and the end of inquiry is discovery. But no one can discover what is false; nor can those things which continue uncertain be discovered. But when those things which have, as it were, been under a veil, are laid open, then they are said to be discovered; and so reason contains the beginning of inquiry, and the end of perceiving and comprehending. Therefore the conclusion of an argument, which in Greek is called ἀπόδειξις, is thus defined:—Reason, which leads one from facts which are perceived, to that which was not perceived. IX. But if all things which are seen were of that sort that those men say they are, so that they either could possibly be false, or that no discernment could distinguish whether they were false or not, then how could we say that any one had either formed any conclusion, or discovered anything? Or what trust could be placed in an argument when brought to a conclusion? And what end will philosophy itself have, which is bound to proceed according to reason? And what will become of wisdom? which ought not to doubt about its own character, nor about its decrees, which philosophers call δόγματα; none of which can be betrayed without wickedness. For when a decree is betrayed, the law of truth and right is betrayed too. From which fault betrayals of friendships and of republics often originate. It cannot, therefore be doubted, that no rule of wisdom can possibly be false; and it ought not to be enough for the wise man that it is not false, but it ought also to be steady, durable, and lasting; such as no arguments can shake. But none can either be, or appear such, according to the principle of those men who deny that those perceptions in which all rules originate are in any respect different from false ones; and from this assertion arose the demand which was repeated by Hortensius, that you would at least allow that the fact that nothing can be perceived has been perceived by the wise man. But when Antipater made the same demand, and argued that it was unavoidable that the man who affirmed that nothing could be perceived should nevertheless admit that this one thing could be perceived,—namely, that nothing else could,—Carneades resisted him with great shrewdness. For he said that this admission was so far from being consistent with the doctrine asserted, that it was above all others