Re: Maximizing vs proving friendliness

From: Matt Mahoney (
Date: Fri May 02 2008 - 09:29:58 MDT

--- Tim Freeman <> wrote:

> >A faster algorithm (only 2^818 steps*) would
> >be to enumerate all laws of physics until a universe supporting
> >intelligent life is found.
> Where's the connection with humanity in that scheme? You might get a
> connection with some imagined form of intelligent life, but there's
> no reason to expect us to be like them.
> I don't know how to write code that even in principle could test for
> the presence of intelligent life in a simulated universe, so I
> wouldn't know how to get started with that.

You could test each planet at one year intervals in each candidate
universe for a signal that is unlikely to be generated anywhere except
on Earth in this universe in 2008. Then use the human utility function
generated by that model.

The signal does not have to be very large. There are 2^409 candidate
universes, about 2^100 Earth masses in the current universe, and a time
span of 2^34 years. If you can tolerate a probability of error of p,
then your signal only needs an algorithmic complexity of
409+100+34+log2(1/p) = 543+log2(1/p) bits, although for safety it
should be a little larger because algorithmic complexity is hard to
compute. I think a JPEG image of a debate between Clinton and Obama
would be sufficient for an astronomically low probability of modeling
the wrong species.

-- Matt Mahoney,

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