Re: [agi] A difficulty with AI reflectivity

From: Wei Dai (weidai@weidai.com)
Date: Fri Oct 22 2004 - 05:04:46 MDT


On Thu, Oct 21, 2004 at 04:10:57AM -0400, Eliezer Yudkowsky wrote:
> One way that might succeed in salvaging the Godel-Machine formalism would
> be to isolate the rewriting of the theorem verifier from the rewriting of
> the rest of the Godel Machine. [...]

I don't think this is necessary. Everything you describe can be
accomplished by carefully choosing the axioms built into the initial
theorem verifier, without changing the formalism itself. The utility
function would be built into the axioms. The verifier will only accept a
proposed rewrite if it comes with a proof that expected utility is
increased, and the axioms could be chosen so that the only way to prove
that a rewrite of the verifier increases expected utility is to prove that
the new verifier accepts exactly the same set of proofs that the old
verifier does, but faster. Even the claim that the verifier can be
rewritten out is correct -- it will do that when a proof appears that no
further self-optimization is likely to be found, therefore a verifier is
no longer needed. At that point the AI will rewrite itself to remove the
proof searcher/verifier and disallow any further modifications.

Such a system will likely miss a lot of opportunities for improvement
(i.e., those that can't be proved using the built-in axioms). I think
Schmidhuber acknowledged this in his paper. The axioms might also have
bugs leading to unintended consequences, which the AI would not be able to
fix. For example the utility function could be defined carelessly. (And
for a general AI I don't see how it could be defined safely.) This is a
problem inherited from AIXI which Schmidhuber doesn't seem to address.



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