Brent Meeker wrote:
I don't think the calculation has to be reversible in order to be the calculation of a reversible phenomena. We use irreversible computations all the time to calculate simple Newtonian processes which are certainly reversible.
I agree that a computation of a reversible phenomenon could make use of non-revsible computations, but the bigger question is: are any reversible physical processes that cannot be simulated using only reversible computations? I haven't been able to think of any such examples off hand, but if you are aware of any I would be interesting in seeing them.
They could simulate a smaller or simpler universe, which is what, for example, a computer game does. The irreversible computation just dumps entropy into the universe which is far below it's maximum entropy (thanks to inflation). This of course depends on a a coarse-grained view of entropy. At the microscopic level, if we could keep track of all the quantum entanglement we'd presumably see that the fine-grained entropy doesn't increase.
Even if the simulated universe was much smaller and simpler than their own, each time a non-reversible computation was performed it would decrease the amount of useful energy available to that civilization, and when that amount reached zero they would die. Note that I am also assuming that the minds of everyone in such a civilization are also being computed on this maximally efficient computer which is designed to run forever. Therefore those inside it would be averse to running any computations that would deplete useful energy, even if only a small amount. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~----------~----~----~----~------~----~------~--~---
