----- Original Message ----- From: "Hal Finney" <[EMAIL PROTECTED]> To: <firstname.lastname@example.org> Sent: 09 January 2005 16:21 Subject: Re: Belief Statements > Alastair Malcolm writes: > > For my own part, I give strong credibility (>50%) to the existence of many > > worlds in some guise or other, and in particular to the existence of all > > logically possible(*) worlds (alpw). For me the existence of one world > > (ours) so conveniently life-suited - sufficiently spatio-temporally extended > > and quiescent but with particular properties enabling wide diversity in > > chemistry etc - demands a specific explanation, and the only other candidate > > final explanation - a Creator (say a God, or a 'higher' civilisation) - > > suffers (at least) the problem of requiring an explanation for *it*. > > That's a great question. I agree that assuming that this is the only > world is quite problematic. On the other hand it does not necessarily > follow that all possible or conceivable worlds exist. From hearing > some physicists speak, I get the impression that they are being "dragged > kicking and screaming" towards many worlds and anthropic ideas, but are > resisting. They still hope to come up with some kind of mathematical or > philosophical reason to at least restrict the number of possible worlds.
I would be interested to know if anyone could think of any possible mathematical or philosophical restriction that that could be, other than deductive logic itself. > At a minimum they are looking for dependencies among many superficially > independent aspects of the observable universe. In fact, you could > describe that as the fundamental goal of physics. They might accept > that certain physical constants have a certain accidental or contingent > aspect, that there is no fundamental reason why they have those values; > but they want to minimize the number of constants for which this is > true, and find ways to show that other constants and properties depend > on these few arbitrary ones. Unfortunately all the basic physical principles that frame any minimisation of the number of arbitrary constants are themselves based solely on what happens to occur in our particular universe. > I also think that AUH (all universe hypothesis) admits too many > alternative formulations which may not all be consistent. That would seem > to force the metaverse to choose between, say, Schmidhuber and Tegmark. > Yet how can that be? It doesn't seem to make sense that there are two > inconsisent ways that all universes can exist. One must be careful that the mode-of-representation tail doesn't wag the physical dog: the neutrality of not giving preference to any particular complete entity itself (both in terms of number, or just existence) implies that it is what the representation *refers to* that is crucial, so any inconsistencies in, say, measure between modes of representation merely reflect the fact that different codes within a mode (bit strings, mathematical forms etc) can in certain circumstances refer to the same entity. (This is not to devalue their potential role, when used carefully, as a guide in overall relative measure estimates.) Alastair