Hi Greg,

On 15 Jun 2008, at 10:40, Greg Egan wrote: >> >> My attributes (eg >> height, weight and so on) are all drawn from distributions of such >> attributes. Why not some hypothetical property like "observer class" >> as set up in this toy problem? > > Why is your height and weight drawn from a certain distribution? It's > because you've been exposed to certain statistical influences on those > attributes, and those influences are influences that you have in > common with a certain subset of the human population. But it would be > absurd to say that *your* height and weight is drawn from the > distribution of heights and weights of all living creatures in the > history of the universe. Equally, it would be absurd to say that your > observer class has been drawn from the distribution of all observers > in the history of the universe. I agree, and I think one half of the everything-list participants agree on this (cf our Relative versus Absolute Self-Sample Assumption debates). The probabilities are relatively conditioned on the "brain/ body" states *histories*, and things are not so different from Feynman integral formulation of QM. Now, the question is "why *quantum* histories". My point is that if we assume we are turing-emulable, then the probabilities have to be derived from a sum on *all* computations. Not just the quantum one. This means we can test the computationalist theory by comparing the sum on all quantum histories/computations (with its weird probability/ amplitude relation) and the sum on all histories/computations. At first sight the comp theory is false because it leads to many more white rabbits than the quantum, but by taking into account constraints related to incompleteness phenomena and logic of self-references, there are (rather technical alas) evidences that the third person white rabbits go away too. It remains abnormally too much first person white rabbits, and I am a bit stuck on that. QM, and physics in general, per se, does not even address those first person purely qualia rabbits (although Galileo, Einstein, Boscovitch, Everett, .Wheeler, Rossler, ... can be seen as a sequences of physicists converging to that. Assuming we are turing emulable, we have to "radicalize" Everett. We have to justify why, in appearance, the QM computations wins in the observable game. All the pieces of the puzzle are there. Greg, I have read and appreciate very much your "Permutation City" novel, but to be honest, I see you still believe "physics" study what there is. This seems to prevent you to follow your own logical line. See my Sane04 paper for an argument (in english) showing that IF we are turing emulable, THEN the observable is just what emerges from all possible local merging and differentiations of computational histories (= as seen as first person point of view, probably plural first person. Merging works through amnesia, and I don't explicitly tackle merging in my publications). In "Laws without Laws", or "It from bits" John Archibald Wheeler got that point: the physical laws emerges on something non-physical. Assuming we are digital machine, that non-physical stuff has not to be more than the additive and multiplicative properties of natural numbers. Poetically: what we take for being the physical reality is in fact the border of the ignorance of self-introspecting universal machine/number ("us"). That "Ignorance" is *very* big, and productive, almost "alive" when seen from inside. And mathematically tractable by computer science/recursion theory. To sum up in a Soccer way: Plato 1, Aristotle 0. (I don't pretend the match is over!) But I think a lot that QM confirms already the comp hypothesis, and the non-materiality of matter. To sum up in a Kronecker's way: God creates the natural numbers, all the rest are web of coherent (and less coherent) dreams by natural numbers. I think I have an argument showing that the comp hyp reduces the mind- body problem into a pure body problem. The problem now is that most physicist takes bodies from granted, and this prevents the understanding of the argument. But that is "religion". (For example, Vic Stenger in his "God, the failed hypothesis" identifies material with natural, and immaterial with supernatural, making math and logic, what? parapsychology? Theology perhaps. At least physicists like Penrose, Wheeler, Deutch, Tegmark are aware of the mathematical reality. Only logicians seems to be aware of (and familiar with) the intricacy of digital self-reference. It is pity that the gap between logicians, physicists and philosopher of mind/ theologian remain so wide. At more than one level, I'm afraid. I am quite opposed to creationism and any "authoritative" bible-god crackpot theology, but many scientists aggravate the hiatus by being a bit dogmatic on matter like if we would have solved the mind-body problem. My modest work, and our discussions here, just points toward a "scientific" formulation of that old problem. Some believe that science is ending. I believe that it has not yet begun (abstracting from -500 to +500 perhaps ...) Best regards, Bruno http://iridia.ulb.ac.be/~marchal/ --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~----------~----~----~----~------~----~------~--~---