When a thing — like the persisting Ship of Theseus — is a logical construction out of more fundamental entities, questions of identity through time become somewhat conventional. Thus Theseus 2 can be identical with Theseus 1 only in a “loose and popular” sense of ‘identical’. In the “strict and philosophical” sense a collection of parts, C1, can be identical with a collection of parts, C2, only if C1 and C2 contain exactly the same parts. In this strict sense, Theseus 2 is not identical with Theseus 1.