[schiffern]

>if those decisions are identical to yours, isn't that entity "you" in some sense?

If by "decisions" you mean every single nerve impulse in response to every possible set of stimuli, then that's pretty exacting. Every wobble while standing, every mouth movement answering any possible question, etc.

Also, how do you determine if the responses are "identical?" It's not like we can rewind reality and play it back, substituting yourself for an AI. And due to quantum nondeterminism, even if you played it back with no substitution your actions will diverge over time! If you're not considered identical to yourself, how is that a useful definition/test of "identicality"?

At the required fidelity, this thought-experiment is problematic both in theory and in practice. It obscures more than it illuminates imo.