Re: Computational irreducibility and the simulability of worlds

From: Hal Finney <>
Date: Sat, 17 Apr 2004 01:03:03 -0700

Eric Hawthorne writes:
> So does that mean we just say "think of the substrate of the universe as
> being a turing machine equivalent",
> any old turing machine equivalent. Ok, but still, you have to admit that
> every "easy to think of" instantiation
> of a turing machine (e.g. a PC with a lot of time on its hands) is a
> terribly implausible universe substrate.
> For heavens sake, the PC with a lot of time on its hands presupposes
> time (and space (i.e. different localities,
> with notions of adjacency), in which to write the tape). Classic
> chicken and egg problem.
> Does anyone know the way out of that particular conceptual pickle?

How about Tegmark's idea that all mathematical structures exist, and we're
living in one of them? Or does that require an elderly mathematician,
a piece of parchment, an ink quill, and some scribbled lines on paper in
order for us to be here?

It seems to me that mathematics exists without the mathematician.
And since computer science is a branch of mathematics, programs and
program runs exist as well without computers.

Hal Finney
Received on Sat Apr 17 2004 - 04:05:40 PDT

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