The relevant posts are Identity Isn’t In Specific Atoms, which uses MWI, and Timeless Identity, which uses MWI and timeless physics. Timeless physics is also mentioned in this post of the free will sequence, but I never really got the impression that it’s essential to the reduction of free will—the parts about possibility and levels of description when talking about minds seemed more important.
The relevant posts are Identity Isn’t In Specific Atoms, which uses MWI, and Timeless Identity, which uses MWI and timeless physics. Timeless physics is also mentioned in this post of the free will sequence, but I never really got the impression that it’s essential to the reduction of free will—the parts about possibility and levels of description when talking about minds seemed more important.