Since reason is the faculty which analyses and perfects the rest, and it ought itself not to be unanalysed, by what should it be analysed? for it is plain that this should be done either by itself or by another thing. Either, then, this other thing also is reason, or something else superior to reason; which is impossible. But if it is reason, again who shall analyse that reason? For if that reason does this for itself, our reason also can do it. But we shall require something else, the thing, will go on to infinity and have no end. Reason therefore is analysed by itself. “Yes: but it is more urgent to cure (our opinions) and the like.” Will you then hear about those things? Hear. But if you should say, “I know not whether you are arguing truly or falsely,” and if I should express myself in any way ambiguously, and you should say to me, “ Distinguish,” I will bear with you no longer, and I shall say to “It is more urgent.” This is the reason, I suppose, why they place the logical art first, as in the measuring of corn we place first the examination of the measure. But if we do not determine first what is a modius, and what is a balance, how shall we be able to measure or weigh anything?

In this case, then, if we have not fully learned and accurately examined the criterion of all other things, by which the other things are learned, shall we be able to examine accurately and to learn fully anything else? “Yes; but the modius is only wood, and a thing which produces no fruit.” But it is a thing which can measure corn. “Logic also produces no fruit.” As to this indeed we shall see: but then even if a man should rant this, it is enough that logic has the power of distinguishing and examining other things, and, as we may say, of measuring and weighing them. Who says this? Is it only Chrysippus, and Zeno, and Cleanthes? And does not Antisthenes say so? And who is it that has written that the examination of names is the beginning of education? And does not Socrates say so? And of whom does Xenophon write, that he began with the examination of names, what each name signified? Is this then the great and wondrous thing to understand or interpret Chrysippus? Who says this? What then is the wondrous thing? To understand the will of nature. Well then do you apprehend it yourself by your own power? and what more have you need of? For if it is true that all men err involuntarily, and you have learned the truth, of necessity you must act right. “But in truth I do not apprehend the will of nature.” Who then tells us what it is? They say that it is Chrysippus. I proceed, and I inquire what this interpreter of nature............