Of the word ΕΙ engraven over the gate of Apollo's temple at Delphi (13)

Having here stopped a little, and made a small pause between, I said: What a fault, O Eustrophus, were we like to have committed, having almost passed by Homer, as if he were not the first that distributed the world into

five parts, who assigned the three which are in the midst to three Gods, and left the two extremes, Olympus and the Earth—of which one is the limit of things above, the other of things below—common and undistributed.[*] But we must, as Euripides says, return to our discourse. For those who magnify the quaternary, or number of four, teach not amiss, that every solid body had its generation by reason of this. For since every solid consists in length and breadth, having withal a depth; and since before length there is extant a point, answerable to unity, and length without breadth is called a line and consists of two; and the motion of a line towards breadth exhibits also the procreation of a superficies in the number three; and the argumentation of this, when depth is added to it, goes on to a solid in the number four; it is manifest to every one, that the quaternary, having carried on Nature hitherto, and even to the perfecting of a body and the exhibiting it tangible, massy, and solid, has yet at last left it wanting the greatest accomplishment. For that which is inanimate is, to speak sincerely, orphan-like, imperfect, and fit for nothing at all, unless there is some soul to use it; but the motion or disposition introducing a soul, being a change made by the number five, adds the consummation to Nature, and has a reason so much more excellent than the quaternary, as an animal differs in dignity from that which is inanimate. Moreover, the symmetry and power of this number five, having obtained greater force, has not permitted the animate body to proceed to infinite sorts, but has exhibited five species of all things that have life. For there are Gods, Genii, and heroes, and then after them the fourth sort is men, and the fifth and last the irrational and brutish animal. Furthermore, if you divide the soul itself according to its nature, its first and most obscure part or faculty is the vegetative, the second the sensitive, then the concupiscible, after that the irascible; and having brought on and perfected Nature in the faculty of the rational, it rests in this fifth, as in the top of all.