Heraclitus on Rivers

Nobody steps into the same river twice.
The same river is never the same
Because that is the nature of water.
Similarly your changing metabolism
Means that you are no longer you.
The cells die, and the precise
Configuration of the heavenly bodies
When she told you she loved you
Will not come again in this lifetime.

You will tell me that you have executed
A monument more lasting than bronze;
But even bronze is perishable.
Your best poem, you know the one I mean,
The very language in which the poem
Was written, and the idea of language,
All these things will pass away in time.

~Derek Mahon