I agree with you on unpredictability not being important for agency, but I don’t understand the last third of this comment. What is the point that you are trying to make about bi-directional determinism? Specifically, could you restate the mistake you think Aaronson is making in the “our choices today might play a role” quote?
Sorry, I was unclear. I don’t think that’s a mistake at all! The only “problem” is that it may be an understatement. On a bi-directional determinist picture, our choices today utterly decisively select one past, in a logical sense. That is, statements specifically describing a single past follow logically from statements describing our choices today plus other facts of today’s universe. The present still doesn’t cause the past, but that’s a mere tautology: we call the later event the “effect” and the earlier one the “cause”.
our choices today utterly decisively select one past, in a logical sense
That’s not necessarily true if multiple pasts are consistent with the state of the present, right? In other words, if there is information loss as you move forward in time.
Indeed. Those wouldn’t be bi-directional determinist theories, though. Interestingly, QM gets portrayed a lot like a bi-directional determinist theory in the wiki article on the black hole information paradox. (I don’t know enough QM to know how accurate that is.)
I agree with you on unpredictability not being important for agency, but I don’t understand the last third of this comment. What is the point that you are trying to make about bi-directional determinism? Specifically, could you restate the mistake you think Aaronson is making in the “our choices today might play a role” quote?
Sorry, I was unclear. I don’t think that’s a mistake at all! The only “problem” is that it may be an understatement. On a bi-directional determinist picture, our choices today utterly decisively select one past, in a logical sense. That is, statements specifically describing a single past follow logically from statements describing our choices today plus other facts of today’s universe. The present still doesn’t cause the past, but that’s a mere tautology: we call the later event the “effect” and the earlier one the “cause”.
That’s not necessarily true if multiple pasts are consistent with the state of the present, right? In other words, if there is information loss as you move forward in time.
Indeed. Those wouldn’t be bi-directional determinist theories, though. Interestingly, QM gets portrayed a lot like a bi-directional determinist theory in the wiki article on the black hole information paradox. (I don’t know enough QM to know how accurate that is.)