# Ship of Theseus Logical Paradox Is a famous thought experiment about a fictional Ship of Theseus. The ship departs on a long journey with a cargo full of spare parts and as each of the ship’s parts is damaged the part is replaced. By the time of arrival, the ship does not use any of its original parts. The thought experiment examines the following questions: - Is the ship that arrived the same ship that left the home port? - If not, what happened to the original ship? At what point did it cease to exist? When replacing parts, at what point does the ship stop being the ‘same’ ship? It’s a semantics problem as the concept of ‘sameness’ (equality) is ambiguous. According to the *mereological theory of identity*, an object’s identity is composed of the sum of identities of its component parts and so the original ship ceased to exist as soon as the first plank is replaced. On the other hand, according to the *spatiotemporal continuity theory*, the identity stays the same as long as all changes are gradual. In the case of the Ship of Theseus, the spatiotemporal theory argument seems to make much more sense, until examined further. Suppose the ship is ancient and is currently in a museum. If art thieves connived a plan to steal it by replacing one part a day with a replacement and then reassembled the ship later, who would truly be in possession of the original ship, the thieves or the museum? As with any paradox, there is no simple answer to this one. Any real world questions of the similar nature need to be examined with the context in mind, and the most pragmatic answer chosen for the specific scenario.