In general, a source of unlimited negentropy buys you only a small polynomial increase in the available time and space. So negentropy does matter, but the total amount of computation you can do is dominated by the available space and time rather than the available negentropy.
In the limit where you have exponentially more time than space (say, the universe turns out to be some arbitrary reversible bounded cellular automaton) then entropy does no good at all.
In the limit where you have exponentially more time than space (say, the universe turns out to be some arbitrary reversible bounded cellular automaton) then entropy does no good at all.
Ok, I see, but this assumes that once you’ve completed a computation, a second execution of it has no moral value, right? (Because more negentropy would allow you to drive the reversible computation forward faster and complete more executions in the same available time.)
Yes—if over the course of your computation you explore on a fraction X of all possible states of the computer, a supply of infinite negentropy would allow you to run the computation something like 1/X faster.
In general, a source of unlimited negentropy buys you only a small polynomial increase in the available time and space. So negentropy does matter, but the total amount of computation you can do is dominated by the available space and time rather than the available negentropy.
In the limit where you have exponentially more time than space (say, the universe turns out to be some arbitrary reversible bounded cellular automaton) then entropy does no good at all.
Ok, I see, but this assumes that once you’ve completed a computation, a second execution of it has no moral value, right? (Because more negentropy would allow you to drive the reversible computation forward faster and complete more executions in the same available time.)
Yes—if over the course of your computation you explore on a fraction X of all possible states of the computer, a supply of infinite negentropy would allow you to run the computation something like 1/X faster.