On 30 Aug 2005, at 18:55, [EMAIL PROTECTED] (GK, Godfrey) wrote:



[BM]
As Russell point out to Godfrey, it is important to distinguish sort of constructive physicalism a-la-Schmidhuber, where the physical universe is a computational object and comp where there is no physical universe at all. from this I can conclude you are not reading the posts (still less my papers), and you are fighting an idea you have build from comp.

[GK]
Since you referred me to John Preskill's delightful lectures on quantum computation I figured I may quote you a little jewel I found in there which, though obviously mistaken in terminology, is quite relevant to this point and others you have raised.

About the Measurement Problem (chapt3, pg.50) Preskill points out that "There are at least two schools of thought:

"Platonic": Physics describes reality. In quantum theory "the wave function of the universe" is a complete description
of physical reality"

"Positivist": Physics describes our perceptions. The wave function encodes our state of knowledge, and the task of quantum theory is to make the best possible predictions about the future, given our current state of knowledge. "

The he goes on to defend his choice of the first school:
"I believe in reality. My reason, I think, is a pragmatic one. As a physicist I seek the most economical model that
explains what I perceive. etc..." (you can read the rest...)

Platonists and positivists would certainly scream at this description of their views but I think it shows is that even the staunchest defenders of the Everett interpretation think that by embracing it they are embracing "reality" by which they mean the Physical Reality that, you claim, does not exist ! To me this suggests again that you have a very crooked view of MWI if you think it supports you in any way...



Of course, Everett still postulates EQM, and interpret it in a physicalist way. I have clear that I don't follow him in the sense that, once comp is assumed, my theorem shows that SWE is either redundant or false. Now I am a realist. reality is independent of me, but with comp it just cannot be "physical", unless you redefined "physical" by "observable", but then you need a theory of observation, which is what comp provides freely (with and without YD); and then the physical emerges "logically" from the number theoretical true relations.

Bruno

http://iridia.ulb.ac.be/~marchal/




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