Diogenes Laertius Vitae philosophorum 3.1.11

at least of the things which we are thus talking about now; on the contrary, they existed from all eternity. . . .

A.

But suppose some one chooses to add a single pebble to a heap containing either an odd or an even number, whichever you please, or to take away one of those already there; do you think the number of pebbles would remain the same?

B.

Not I.

A.

Nor yet, if one chooses to add to a cubit-measure another length, ¹ or cut off some of what was there already, would the original measure still exist?

B.

Of course not.

A.

Now consider mankind in this same way. One man grows, and another again shrinks; and they are all undergoing change the whole time. But a thing which naturally changes and never remains in the same state must ever be different from that which has thus changed. And even so you and I were one pair of men yesterday, are another to-day, and again will be another to-morrow, and will never remain ourselves, by this same argument.