Now, if you are thinking along the same lines as Heraclitus ['You can't step into the same river twice'], you might say, 'Aha! But the body is never the same. Body cells are constantly dying off and being replaced, or just dying.' I once had a friend who wanted to use this as a central plank in his petition for divorce, on the grounds that he was no longer the same person as the one who married his wife several years ago. A little philosophy is a dangerous thing.
From Mark Rowlands's book The Philosopher at the End of the Universe: Philosophy Explained through Science Fiction Films.