Tolerance and Counterpart Theory

Many philosophers have thought that Tolerance Puzzles can be easily dissolved by adopting some form of counterpart theory, which is roughly the view that being possibly a certain way is having a counterpart that is that way. This chapter shows how standard versions of counterpart theory involve radical departures from standard modal logic (going far beyond Iteration-denial) which we claim are unacceptable, and argues that once counterpart theory is developed in such a way as to avoid such logical revisionism, it has no special capacity to resolve the puzzles.