At 1/18/02, you wrote:
>I'm not convinced about the models of computation involving GTMs and
>such in Juergen Schmidhuber's paper. Basically these kinds of TMs can
>change their mind about the output, and the machine doesn't know when
>it is through changing its mind. So there is never any time you can
>point to the output or even a prefix and say that part is done. It is
>questionable to me whether this ought to count as computation.
I am currently somewhat in accord with this view. My model of the ensemble
of universes which is just approaching a "finished" condition is not a
computational one. However, without regard to the application of
"computation" to the comprehension of this ensemble I do not see an
external difference between any of Juergen's machines and the usual
UTM. Whenever a prefix is indeed done that is just the same as any
external output of a UTM with the computation activity spread over a long
section of tape internally IMO.
As to the discussions of measure and probability re the likelihood of a
particular sort of universe I do not see the point. The core idea for a
founding postulate that seems most appealing is that no information
exists. So the entire discussion re measure IMO is just an effort to
extract a factual(s) from an ensemble of counterfactuals.