 ST2 relies on two seemingly innocuous inferences: (a) from its being indeterminate whether Theseus II is identical to the mended ship to Theseus II’s being indeterminately identical to the mended ship and (b) from there to Theseus II’s having the property of being indeterminately identical to the mended ship. ST3 seems trivial as well: the mended ship is definitely self-identical, so it does not itself have this property. ST4 looks to be an immediate consequence of Leibniz’s Law: if Theseus II and the mended ship differ with respect to even one property, then they are distinct. ST5 is trivial: if they’re not identical, then it isn’t indeterminate whether they are  identical.[29] 