According to Wikipedia, the Ship of Theseus problem questions whether an object that has had all of its components replaced is still fundamentally the same object.
<pedantry> If each part is replaced in series, and the identity of the object remains the same after each step, then clearly the object remains the same. For humans identity is thus based on recognizing what you have seen before; it acknowledges mutable state. In this case, if you consider the brand as a mutable property of the object, then yes, the identity of PLT-Scheme and Racket are the same. </pedantry>
Yeah, sorry I didn't make that clear :) PLT Scheme has become Racket... even though its still Scheme.
It looks to me like a lot of the core PLT guys were involved in the R6RS debacle, and didn't like what came out of the process so decided maybe they aren't quite an official "Scheme" anymore per R6RS. Oh the drama...