Re:Accidentally Turing-Complete
by charcircuit on Saturday February 05, 2022 @09:16AM
(#30221177)
>1. All physical systems must eventually halt.
In terms of physical computers I don't agree with must, but I will say there is a very high chance that it will. In terms of an arbitrary physical system something like gravity doesn't just halt.
>In many cases physical systems correspond to formal computational systems.
It is possible to model physical systems. It can also be useful to reason about a simplified model of something.
>So then because the system is deterministic, we know that if it returns to a previous state it must keep returning to this state forever?
Assuming it's deterministic then yes. Depending on how complicated your model is it may be hard to go back to a state you were in before.
In terms of physical computers I don't agree with must, but I will say there is a very high chance that it will. In terms of an arbitrary physical system something like gravity doesn't just halt.
>In many cases physical systems correspond to formal computational systems.
It is possible to model physical systems. It can also be useful to reason about a simplified model of something.
>So then because the system is deterministic, we know that if it returns to a previous state it must keep returning to this state forever?
Assuming it's deterministic then yes. Depending on how complicated your model is it may be hard to go back to a state you were in before.
>Maybe, a period of time with no end?
Sure.