Or so they say--"they" being dead, though.
Hat tip: Heraclitus, known for, among other things, pointing out: "No man ever steps in the same river twice, for it is not the same river and he is not the same man." Or as Socrates/Plato nicely puts it in Cratylus, "Heraclitus is supposed to say that all things are in motion and nothing at rest; he compares them to the stream of a river, and says that you cannot go into the same water twice" (402a, Jowett translation).
That sounds about right, though notice how Plato leaves out the bit about "not the same man." Change was a real problem for the ancients. That still hasn't changed, I suppose. (Sorry for the clunky play on words.)
Let's step into the stream.