I comment last posts by Russell, Alasdair, George. I am very glad with the fact that people here are aware of the flying white rabbit appearance problem in Tegmark/Schmidhuber-like approach.
I really think that it is not possible to solve the rabbit problem with Tegmark hypothesis (that all mathematical structures exist), because it makes the indeterminism domain to big. The more we make Tegmark's hypothesis precise, the more will it be likely that we should seen white rabbit flying ... I agree with Russell Standish when he says that the anthropic principle per se cannot solve the rabbit problem. I agree with George Levy when he says that <<The ultimate anthropic principle is relative... or relativistic with respect to the observer and pushes the anthropic concept to its ultimate conclusion: The Self.>> With the computationalist hypothesis we can replace the "anthropos" by the Universal Turing Machine, i.e. we can work with the computational self, and the logic of self-reference. In that case it becomes more easy to tackle the rabbit issue. The set of all computations is well defined thanks to Church's thesis. And there is no infinite chain of turtle problem because there is no need for an actual implementation of the universal dovetailer as we discuss it before. There is a "feeling of actualness" for any relative, arithmetically well defined, self. The rabbit issue is thus linked to the measure definition issue. Of course with comp we can no more distinguih in an absolute way dream from "reality" and we must explain why some dreams seems to be stable and coherent (without flying rabbit). So, of course, we are push back in the "Wei Dai" question: should we follow the RELATIVE SSSA or the STRONG SSSA here ? What George call rightly the crux of the matter. To sum up : The immortality question is not linked to the measure problem ; The white rabbit problem is definitely linked to the measure problem (and to what I like to call the REVERSAL between "physics" and "psychology" : with comp, it is the physical NON-WEIRDNESS which is weird!). Bruno
