RE: Are we simulated by some massive computer?

From: Bruno Marchal <>
Date: Wed, 14 Apr 2004 16:13:46 +0200

At 09:58 13/04/04 -0400, Ben Goertzel wrote:

> > 6) This shows that if we are in a massive computer running in
> > a universe, then (supposing we know it or believe it) to
> > predict the future of any experiment we decide to carry one
> > (for example testing A or B) we need to take into account all
> > reconstitutions at any time of the computer (in the relevant
> > state) in that universe, and actually also in any other
> > universes (from our first person perspective we could not be
> > aware of the difference of universes from inside the computer).
>Yes, but this is just a fancy version of the good old-fashioned Humean
>problem of induction, isn't it?

That would be the case if there were no measure on the computations.

>Indeed, predicting the future on a sound "a priori" basis is not
>possible. One must make arbitrary assumptions in order to guide
>This is a limitation, not of the "comp" hypothesis specifically, but of
>the notion of prediction itself.
>You cannot solve the problem of induction with or without "comp", so I
>don't think you should use problem-of-induction related difficulties as
>an argument against "comp."

I was not arguing against comp! (nor for).

>In fact, "comp" comes with a kind of workaround to the problem of
>induction, which is: To justify induction, make an arbitrary assumption
>of a certain universal computer, use this to gauge simplicity, and then
>judge predictions based on their simplicity (to use a verbal shorthand
>for a lot of math a la Solomonoff, Levin, Hutter, etc.). This is not a
>solution to the problem of induction (which is that one must make
>arbitrary assumptions to do induction), just an elegant way of
>introducing the arbitrary assumptions.

This can help for explaining what intelligence is, but cannot help
for the mind body problem where *all* computations must be taken into

>So, in my view, we are faced with a couple different ways of introducing
>the arbitrary assumptions needed to justify induction:
>1) make an arbitrary assumption that the apparently real physical
>universe is real
>2) make an arbitrary assumption that simpler hypotheses are better,
>where simplicity is judged by some fixed universal computing system
>There is no scientific (i.e. inductive or deductive) way to choose
>between these. From a human perspective, the choice lies outside the
>domain of science and math; it's a metaphysical or even ethical choice.

I am not convinced. I don't really understand 1), and the interest of 2)
relies, I think, in the fact that simplicity should not (and does not, I'm sure
Schmidhuber would agree) on the choice of the universal computing

Received on Wed Apr 14 2004 - 11:14:39 PDT

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