“Ship of Theseus”? It’s in reference to a ship which was used to row out to Delos every year for a ritual, but it was very specific that it had to be the same boat that Theseus used. So, as the pieces broke and had to be replaced, eventually every original plank, nail and line would have been replaced. After all of those replacements, which occurred one at a time over decades, is it still the same boat? If you collected all of the old replaced bits of the original boat, then put them together into a boat, would that be the original ship? At what point does it stop being the “ship of Theseus”?