Of the word ΕΙ engraven over the gate of Apollo's temple at Delphi (18)

For we indeed do not at all essentially partake of being; but every mortal nature, being in the midst between generation and corruption, exhibits an appearance, and an obscure and weak opinion of itself. And if you fix your thought, desiring to comprehend it,—as the hard grasping of water, by the pressing and squeezing together that which is fluid, loses that which is held,—so when reason pursues too evident a perception of any one of the things subject to passion and change, it is deceived and led away, partly towards its generation and partly towards its corruption, being able to apprehend nothing either remaining

or really subsisting. For we cannot, as Heraclitus says, step twice into the same river, or twice find any perishable substance in the same state; but by the suddenness and swiftness of the change, it disperses and again gathers together, comes and goes. Whence what is generated of it reaches not to the perfection of being, because the generation never ceases nor is at an end; but always changing, of seed it makes an embryo, next an infant, then a child, then a stripling, after that a young man, then a full-grown man, an elderly man, and lastly, a decrepit old man, corrupting the former generations and statues by the latter. But we ridiculously fear one death, having already so often died and still dying. For not only, as Heraclitus said, is the death of fire the generation of air, and the death of air the generation of water; but you may see this more plainly in men themselves; for the full-grown man perishes when the old man comes, as the youth terminated in the full-grown man, the child in the youth, the infant in the child. So yesterday died in to-day, and to-day dies in to-morrow; so that none remains nor is one, but we are generated many, according as matter glides and turns about one phantasm and common mould. For how do we, if we remain the same, delight now in other things than we delighted in before? How do we love, hate, admire, and contemn things contrary to the former? How do we use other words and other passions, not having the same form, figure, or understanding? For neither is it probable we should be thus differently affected without change, neither is he who changes the same. And if he is not the same, neither is he at all; but changing from the same, he changes also his being, being made one from another. But the sense is deceived through the ignorance of being, supposing that to be which appears.