"The Ship of Theseus, also known as Theseus' paradox is a paradox that raises the question of whether an object which has had all its component parts replaced remains fundamentally the same object.
The paradox was first raised in Greek legend as reported by Plutarch,
"The ship wherein Theseus and the youth of Athens returned [from Crete] had thirty oars, and was preserved by the Athenians down even to the time of Demetrius Phalereus, for they took away the old planks as they decayed, putting in new and stronger timber in their place, insomuch that this ship became a standing example among the philosophers, for the logical question of things that grow; one side holding that the ship remained the same, and the other contending that it was not the same."
Plutarch thus questions whether the ship would remain the same if it were entirely replaced, piece by piece. Centuries later, the philosopher Thomas Hobbes introduced a further puzzle, wondering: what would happen if the original planks were gathered up after they were replaced, and used to build a second ship. Which ship, if either, is the original Ship of Theseus?
Another early variation involves a scenario in which Socrates and Plato exchange the parts of their carriages piece by piece until, finally, Socrates's carriage is made up of all the parts of Plato's original carriage and vice versa. The question is presented if or when they exchanged their carriages."
-> The human body constantly creates new cells as old cells die. The average age of non-bone cells in an adult body may be less than 10 years. The body is analogous to Heraclitus' river in that it consumes and expels a steady flow of nutrients, gas and water, all of it processed by cell bodies and enzymes that are themselves destroyed and remade.
-> Ghost in the Shell cyclically returns to this paradox of a "human" whose body is replaced by artificial parts.