Theseus' Ship Changes and Yet Remains Theseus' Ship

IntroductionWelcome people of DDO! This debate is going to be about the famous Ship of Theseus. It is very nice to see a philosophy debate not concerned with God's existence. My opponent starts out with the following."I propose to solve the paradox of Theseus' Ship", therefore the onus is on him and I am merely going to show why his proposal does not work.The ParadoxThere are many compelling solutions, this one however is unfortunately not one of them. The reason for this is a misunderstanding of the paradox. Let's recap the paradox, shall we?"The ancient historian Plutarch recounts the story of the famous ship of Theseus, which was displayed in Athens for many centuries. Over time, the ship's planks wore down and were gradually replaced. [...] Suppose that a custodian collects the original planks as they are removed from the ship and later puts them back together in the original arrangement. In this version of the story, we are left with two seafaring vessels, one on display in Athens and one in the possession of the custodian. But where is the famous Ship of Theseus?"(1)This is a problem for identity, "self-sameness". It's about what criteria we have to say that something is the same over time.My Opponent's SolutionPro solution is at it's core the claim that what makes Theseus' ship, Theseus' ship is that he is the one claiming it as property. One can therefore change parts of the ship without breaking the ownership relation.I think there are two possible readings of my opponent's account.The first is that Theseus' ship is whatever is owned by Theseus and is a ship. This would miss the point entirely, since the paradox of Theseus' ship is not actually about Theseus' at all, it is about the identity of the ship itself.Leibniz’s law: the metaphysical principle that necessarily, if a and b are identical, then they must share all of the same properties.(2)But the ship Theseus' owns first is completely different from the ship he owns afterwards. 'Theseus' ship' is to be understood as an indexical.Indexical: a linguistic expression whose reference can shift from context to context. For example, the indexical ‘you’ may refer to one person in one context and to another person in another context.(3)E.g., "I like cats" when uttered by me is true, uttered by someone else it might be false.The second, rather interesting reading is, that the ownership relation is of some privileged metaphysical significance.I think there is much to say about this, however I am going to constrain myself to only one point, the claim that some relation like ownership is an essential property of an object.Consider me, Fkkize, having some friend, John. 'Fjf' describes the relation 'John is a friend of Fkkize'. Say we have been friends over the past ten years. Of course I am the same person as last year, I am still Fkkize and I am presumably going to be the same person next year.Now say our friendship ends tomorrow, and the relation 'Fjf' no longer holds, am I not Fkkize anymore? Of course I'm still Fkkize!Similarly when considering the ship of Theseus' we can ask ourselves, is ownership, which is not even a natural kind but a social one, really necessary for the ship's identity?Imagine Theseus' ship laying at anchor in some city. You, a super intelligent being, examine the ship in all its detail. The next day Theseus' dies and according to Pro Theseus' ship is no longer Theseus' ship anymore, but just some ship. You are unaware of this and examine the ship again, would find any differences? I think not.He then continues to give a somewhat convoluted definite description of a ship:"ShipD = (x+WB) + Ka + Mb + Wc + (y+S)"This seems to be attempted translation into first order logic, but it fails right from the start.Capital letters denote predicates ("...is a dog"), lower case letters from the denote subjects/ objects and lower case letters from the end of the alphabet denote variables.X and y are not in the scope of any quantifier (invalid) and most importantly, he uses a, b and c (objects) which means this is not a description of a ship in the general sense, it is a description of one single ship. This is not what he is going for, since his solution revolves around deciding which ship is Theseus' ship by means of an ownership relation.Here is a correct translation of the description of a ship made of wooden planks, a keel, a masthead, a wheel and a sail.Ax((Wx & Kx & Mx & Sx) & Ey (Ty & (x=y)))For all x, x is made of wooden planks & x has a keel & x has a masthead & x has a sail & there exists some y, such that y is a ship and x is identical to y.ConclusionMy opponent presents an interesting solution, however, it faces a multitude of problems and is ultimately not what the paradox asks for.The resolution is negated.Sources(1) http://plato.stanford.edu...(2) Alyssa Ney, An Introduction to Metaphysics, p. 95(3) http://plato.stanford.edu...