And in some cases the name of the idea is not only attached to the idea in an eternal connection, but anything else which, not being the idea, exists only in the form of the idea, may also lay claim to it. I will try to make this clearer by an example:—The odd number is always called by the name of odd? Very true. But is this the only thing which is called odd? Are there not other things which have their own name, and yet are 104 called odd, because, although not the same as oddness, they are never without oddness?—that is what I mean to ask—whether numbers such as the number three are not of the class of odd. And there are many other examples: would you not say, for example, that three may be called by its proper name, and also be called odd, which is not the same with three? and this may be said not only of three but also of five, and of every alternate number—each of them without being oddness is odd; and in the same way two and four, and the other series of alternate numbers, has every number even, without being evenness. Do you agree? [Sidenote: _Essential opposites and things which admit opposites._] Of course. [Sidenote: Not only essential opposites, but some concrete things which contain opposites, exclude each other.] Then now mark the point at which I am aiming:—not only do essential opposites exclude one another, but also concrete things, which, although not in themselves opposed, contain opposites; these, I say, likewise reject the idea which is opposed to that which is contained in them, and when it approaches them they either perish or withdraw. For example; Will not the number three endure annihilation or anything sooner than be converted into an even number, while remaining three? Very true, said Cebes. And yet, he said, the number two is certainly not opposed to the number three? It is not. Then not only do opposite ideas repel the advance of one another, but also there are other natures which repel the approach of opposites. Very true, he said. Suppose, he said, that we endeavour, if possible, to determine what these are. By all means. [Sidenote: That is to say the opposites which give an impress to other things.] Are they not, Cebes, such as compel the things of which they have possession, not only to take their own form, but also the form of some opposite? What do you mean? I mean, as I was just now saying, and as I am sure that you know, that those things which are possessed by the number three must not only be three in number, but must also be odd. Quite true. And on this oddness, of which the number three has the impress, the opposite idea will never intrude? No. And this impress was given by the odd principle? Yes. And to the odd is opposed the even? True.