On Sat, Jun 24, 2017 at 03:59:56PM +1000, Bruce Kellett wrote: > > Well, I have just taken a quick look. What strikes me is that the > first paragraph of Appendix D defines "Observer moments psi(t) are > sets of possibilities consistent with what is known at that point in > time, providing variation upon which anthropic selection acts. ... > We wish to determine the probability of outcome a being observed." > So you assume a probabilistic model from the outcome. Why would you > do that? Why not a deterministic model?
I do spend over a hundred pages prior to the chapter on QM going into the reasons! But to try to signpost this, and maybe save you the effort of reading my book, the basic reason is that our 1p view must be the result of evolution - not biological evolution, per se, but anthropic evolution - the result of variation of possible futures, and anthropic selection from those possible futures to the actual result seen. Along with heredity (which in QM gives rise to unitarity), we have the three pillars of evolution as espoused by Lewontin. Consequently, the probabilistic model needs to be there right from the start to provide the variation on which anthropic selection acts. > > So you know about QM from the start, and devise a strategy to get > you there. One of the problems that many-worlders face in their > attempts to derive the Born rule from within MWI is that they cannot > independently justify a probabilistic model. Yes, but I don't start with the MWI (namely, I don't start with a Hilbert space and unitary equation of motion - ie Schroedinger's equation). I start with evolution in a generic multiverse. > If you have a > probabilistic model in 3 or more dimensions, Gleason's theorem tells > you that the Born rule is the only consistent model for > probabilities. My arguments go through in fewer than 3 dimensions as well, AFAIK, although that would a relatively uninteresting world - very black and white :). Which is why I suspect it is independent of Gleason. > But you have to say why you want a probabilistic > interpretation in the first place. Deutsch's attempts founder on the > fact that he has to assume that small amplitudes have small > probabilities, even to get started, so his argument is manifestly > circular. > Yes - I think the problem with those approaches is that they start with a Hilbert space and unitary equation of motion (ie a classic MWI), and then fail to generate the Born rule because there is no observer in their mechanics. > > As I said, you build a probabilistic model in at the start, so > Gleason's theorem is going to get you the Born rule automatically. > Or if you don't assume Gleason, you have an equivalent result by > another route. Assuming a probabilistic model is a very powerful > starting point...... Sure - but it is necessary. If evolution did not work the way it did, we could only ever be Boltzmann brains, isolated observers existing fleetingly, barely having time to consider what to have for lunch, let alone figuring out the meaning of the universe. Fortunately for us, evolution does work to generate complex worlds from simple beginnings, meaning an evolved world is overwhelming more likely to occur in the Multiverse of Everything than Boltzmann brain existences. -- ---------------------------------------------------------------------------- Dr Russell Standish Phone 0425 253119 (mobile) Principal, High Performance Coders Visiting Senior Research Fellow hpco...@hpcoders.com.au Economics, Kingston University http://www.hpcoders.com.au ---------------------------------------------------------------------------- -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
