Thanks for throwing in some neat ideas. Doesn't your Second Time Around Problem conclusively answer _every_ question with "there is no way to know," though? For

Thanks for throwing in some neat ideas. Doesn't your Second Time Around Problem conclusively answer _every_ question with "there is no way to know," though? For example: is there really gravity? Suppose there was a universe with gravity. We let that universe run for its lifetime and record everything that happens. Then we play back that recording in a universe where stuff (matter/energy/etc) is not affected by gravity, but instead behaves according to a recording. The two are identical. As another example: did I really write this comment? Perhaps there was another universe where this comment was written, but _this_ universe is just a second-time-around recording where playback was started right after alternate-me hit post. Anyway: the determinism question folks are talking about is, does the current state of the universe dictate the next state? In your playback universe, the answer is no -- you could edit any "frame" arbitrarily without affecting the frames that follow.