Parmenides (155)

Then that which came into being later, becomes older in relation to the older, which came into being earlier; yet it never is older, but is always becoming older; for the latter always tends towards being younger, and the former towards being older. And conversely the older becomes in the same way younger than the younger. For as they are moving in opposite directions, they are becoming the opposites of one another, the younger older than the older, and the older younger than the younger; but they cannot finish the process of becoming; for if they finished the process of becoming, they would no longer be becoming, they would be. But as the case is, they become older and younger than one another—the one becomes younger than the others, because, as we saw, it is older and came into being earlier, and the others are becoming older than the one, because they came into being later. By the same reasoning the others stand in the same relation to the one, since they were seen to be older than the one and to have come into being earlier.

Yes, that is clear.

Then from the point of view that no one thing becomes older or younger than another, inasmuch as they always differ by an equal number, the one cannot become older or younger than the others, nor the others than the one; but in so far as that which comes into being earlier must always differ by a different proportional part from that which comes into being later, and vice versa—from this point of view the one and the others must necessarily become both older and younger than one another, must they not?

Certainly.

For all these reasons, then, the one both is and becomes both older and younger than both itself and the others, and neither is nor becomes either older or younger than either itself or the others.

Perfectly true.

But since the one partakes of time and can become older and younger, must it not also partake of the past, the future, and the present?

It must.

Then the one was and is and will be and was becoming and is becoming and will become.

Certainly.

And there would be and was and is and will be something which is in relation to it and belongs to it?

Certainly.

And there would be knowledge and opinion and perception of it; there must be, if we are now carrying on all this discussion about it.

You are right.

And it has a name and definition, is named and defined, and all the similar attributes which pertain to other things pertain also to the one.

That is perfectly true.

Let us discuss the matter once more and for the third time. If the one is such as we have described it, being both one and many and neither one nor many, and partakes of time, must it not, because one is, sometimes partake of being, and again because one is not, sometimes not partake of being?

Yes, it must.

And can one, when it partakes of being, not partake of it, or partake of it when it does not partake of it?

No, it cannot.

Then it partakes at one time and does not partake at another; for that is the only way in which it can partake and not partake of the same thing.