Re: subjective reality

[Bruno Marchal]

On 30 Aug 2005, at 18:01, [EMAIL PROTECTED] wrote: [GK]  Speculation for me is not a pejorative term, to begin with. Yes, there is a sense in which all theories are speculative but  some have ceased to be purely so because either empirical or heuristic evidence was found in their favor. That is the sense  in which they are no longer considered speculative. So QM, for example, is no longer called a speculative theory, though  people do speculate a lot around it since it poses some serious intepretative problems. The Everett version of QM is either  an interpretation of QM or a better theory (let us call it EQM) depending on whom you ask, and that is actually another  item of speculation, btw. But the people who claim that EQM is a theory need to come up with feasible empirical tests for  which EQM gives predictions distinct from QM. Until these tests are proposed and are performed EQM remains a speculative theory!! My view, as addressed to physicist, is the following. I make it simpler for reason of clarity. Copenhagen QM:  SWE  Unintelligible dualist theory of measurement/observation Everett QM:  SWE  comp theory of observation/cognition Your servitor:  comp. The collapse is a speculation on a theory which does not exist, and which has been invented to make the (isolated, microscopic)  superposition non contagious on the environment. So if you want make the distinction between speculation and hypothesis, I would say the "collapse" is far more speculative. The problem of comp is that machine cannot know if they are supported by any computations and it is up to Everett Deutsch etc. to explain why the quantum computations wins the "observability conditions" on the (well defined by Church  Thesis) collection of all computations. This is not obvious at all and constitutes the first main result I got. For comp "philosophers of mind" (Alias theoretical cognitive scientists), the two main result I got can be seen as a "correction" of the "old" Lucas Penrose argument which try to refute comp by Godel's incompleteness. From this I see only a couple of ways out: Either  1) your derivation leads you not to QM but to a better physical theory with testable empirical predictions that falsify  those of QM, presumably including those that lead to the invalidation of YD. I would very much like to see that theory if you have it! On my web page you can find all the needed programs to run a theorem prover of that physics. With some time and training you could perhaps optimize it and ... refute or confirm comp (admitting quantum logic operates on nature). From what has been already derived, some non trivial quantum logical features did appeared.  2) you actually prove (by non-QM means, I assume) that YD is empirically implementable This is nonsense. Better: with comp it is provably nonsense. (G G* confusion, for those who knows). It is a key point: if comp is true YD will never be proved to be implementable. (It is of the type Dt, or equivalently ~B~t, its truth makes it unprovable). and that would only require  that you replace the experience of one human being (may I suggest yours?) by a digital computer version of the same. That is the act of faith needed for the comp practitionners. Recall that for many people such a question will be a weaker one at first, like should I accept an artificial hyppocampus instead of dying now. Well the real question will be: should I choose a mac, a pc, or what? The fact is that comp can justify by itself why it is a act of faith, and I am not sure it is entirely "comp-polite" to suggest such an operation to anyone but oneself.  (Of course you can always claim that it has already occurred, as you sometimes suggest and that is cute but just plain silly, too. ) I claim this in the context of comp + OCCAM. Amoeba's self-duplication, and even the high sexual reproduction of mammals involved rather clearly digital information processing. Bruno http://iridia.ulb.ac.be/~marchal/