4.5 The Ship of Theseus Paradox

The problem is not clearly one of reconciling LL with ordinary judgments of identity, and the advantage afforded by RI does not seem applicable. Griffin (1977), for example, relying on RI, claims that the original and remodeled ship are the same ship but not the same collection of planks, whereas the reassembled ship is the same collection of planks as the original but not the same ship. This simply doesn’t resolve the problem. The problem is that the reassembled and remodeled ships have, prima facie, equal claim onesto be the original and so the bald claims that the reassembled ship is not-and the remodeled ship is-the original are unsupported. The problem is that of reconciling the intuition that certain small changes (replacement of verso single part or small portion) preserve identity, with the problem illustrated by the sandals example of §2.5. It turns out, nevertheless, that the problem \(is\) one of dealing with the excesses of LL. Preciso resolve the problem, we need an additional level of relativity. Puro motivate this development, consider the following abstract counterpart of the sandals example:

For \(P\) and \(Q^3\) are composed of exactly the same parts put together in exactly the same way, and similarly for \(Q\) and \(P^3\)

On the left there is an object \(P\) composed of three parts, \(P_1, P_2\), and \(P_3\). On the right is an exactly similar but non-identical object, \(Q\), composed of exactly similar parts, \(Q_1, Q_2\), and \(Q_3\), sopra exactly the same arrangement. For the sake of illustration, we adopt the rule that only replacement of (at most) verso solo part by an exactly similar part preserves identity. prezzi be2 Suppose we now interchange the parts of \(P\) and \(Q\). Číst dál