[drudman]

Free will doesn't really enter into it, although in retrospect my analysis made it seem like it did. On the quantum level, there are a large number of possibilities, but as we, the observers, "observe" the actual outcomes of quantum events, we shrink the number of possibilities down to zero. The idea is that if you travelled back, the possibilities have already shrunk to zero, because you have already observed them so there would be no alternatives.

Now, say you were to go into absolute isolation, observing virtually nothing but the inside of a darkened room. If you then went back, there would, in theory, be a large number of possibilities once again, because you would have observed none of the outcomes.

The view that is presented in the first post of this thread is flawed, IMHO. It is avoidable completely if you subscribe to many-worlds hypothesis.