Surely QM + collapse makes the prediction that there is a mechanism that causes the collapse (e.g. Penrose's idea about it being gravitational) and therefore predicts that at some point that mechanism will kick in, so we can only have superpositions up to a particular size? While QM on its own (i.e. Everett) predicts that there is no collapse threshold - that if you can keep a system from decohering, it will remain in a superposition regardless of how large it is.
So at some point QM+Collapse has to come up with a mechanism for collapse, and at that point it becomes testable, at least in theory (depending on our level of technology, I mean). On 10 March 2014 13:17, chris peck <[email protected]> wrote: > Hi Bruno > > > > > > > > > > > > * >> With respect to the UDA, graves and me are just using different > vocabulary. Really? the last time I quoted her: "What ... should > Alice expect to see? Here I invoke the following premise: whatever she > knows she will see, she should expect (with certainty!) to see. So, she > should (with certainty) expect to see spin-up, and she should (with > certainty) expect to see spin-down."But that can only be a 3-1 description. > She handles the 1p by a maximization of the interests of the copies, and > that is equivalent with the FPI, without naming it.* > > > Funnily enough Bruno, if I was opportunistic I would just about accept > that. I mean personally, I would argue that the vocabulary used is > identical between you and Greaves and she explicitly denies your > probability distribution from the first person perspective. But a bigger > problem for you raises its head if I put that to one side. > > if, as you claim, there is no substantive difference between your theory > and Greaves' just because she has some other mechanism of deriving the bare > quantities you want, then you may as well say that there is only a > difference in terminology between your theory and any other interpretation > of QM. After all they all deliver 0.5 by some now irrelevant metric too. > You've just relugated your theory to the purely metaphysical. You're > tacitly admitting that all these theories are just re-skins of the same > underlying engine with bugger all to choose between them. > > In a way that is something that I have felt for a while. Everettian QM > does not improve upon QM + collapse in the way say relativity improves on > Newtonian physics. There is no concomitant improvement in predictive > capability on offer. Its a purely theoretical change intended to smooth out > conceptual difficulties but it can only do that by delivering further > difficulties of its own. All your theories are scientifically irrelevant. > > ------------------------------ > Date: Sun, 9 Mar 2014 11:32:08 -0700 > From: [email protected] > To: [email protected] > > Subject: Re: Tegmark and UDA step 3 > > On 3/9/2014 12:47 AM, Bruno Marchal wrote: > > > On 08 Mar 2014, at 06:16, meekerdb wrote: > > On 3/7/2014 8:26 PM, LizR wrote: > > On 8 March 2014 08:14, meekerdb <[email protected]> wrote: > > On 3/7/2014 1:24 AM, LizR wrote: > > On 7 March 2014 18:29, meekerdb <[email protected]> wrote: > > On 3/6/2014 9:15 PM, Jason Resch wrote: > > A related question is, is there any such thing as true randomness at all? > Or is every case of true randomness an instance of FPI? > > > *Or is FPI just a convoluted way to pretend there isn't true randomness? * > > > If one assumes QM and the MWI are correct then it isn't pretending, > > True; but I don't assume that. > > > Since your original statement above only makes sense in some context - > which you haven't revealed, as far as I can tell - perhaps you could tell > us what you *are* assuming? > > > I'm not assuming anything, I'm just pointing out that one could assume > something different than QM and MWI. For instance, start with MWI but then > suppose that at each "branching" only one instance of you continues. > Doesn't that accord with all experience? > > > Like Ptolemeaus epicycles. The point is to accord with the simplest > theories we have for most if not all experiences, like QM, or > computationalism. > > At each "branching" only one instance of you continue, you say, but that > does not accord well with the simplest explanation of the two slits > experience. You will have to explain why the superpositions act in the > micro and not the macro, and this needs big changes in QM (= SWE), or even > bigger to computationalism. > > > But you have to explain this anyway; except the question is transformed > into why do I only experience one reality. Presumably the answer is in > decoherence and the off-diagonal terms of the density matrix becoming very > small (or maybe even zero). Once you have this answer then you can look at > the density matrix, as Omnes does, and say, "QM is a probabilistic theory, > so it predicts probabilities. What did you expect?" > > My point is that these sharp questions are asked of QM because it is a > mature theory with lots of very accurate predictions, but "comp" as a new > speculative theory kind of gets a free ride on the very same questions, > e.g. why do we not experience superpositions? Why isn't there a > superposition of the M-guy and the W-guy according to comp. How can > consciousness be instantiated by physical processes? Most people on this > list just assume it can't and dismiss the very idea as mere physicalism. > But they don't ask how can consciousness be instantiated by infinite > threads of computation - that's mysterious and consciousness is mysterious, > so it's OK. > > > If not, you can always consistently assume everything is done by a God > to fit your favorite philosophical expectations. You can do that, > *logically*, but this is no more truth research, but wishful thinking. > > > But you know that is not what is done. QM predicts probability > distributions that are confirmed to many decimal places. QFT predicts some > measured values to 11 decimal places. And you rely on QM to explain the > world in in you theory of comp. Your approach is to explain QM and then > let QM do the rest of the work - which is fine. But my point is that QM > can still do the work even if it's a probabilistic theory. So unless comp > can make some better predictions than comp it's just an interpretation and > it's trading off a distaste for randomness (a very restricted and well > defined randomness) for a love of everythingism. Which is why I hope comp > can predict something about consciousness; where it may offer something > beyond just interpretation. > > Brent > > > > Bruno > > > > http://iridia.ulb.ac.be/~marchal/ > > > > -- > 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 [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > > > > -- > 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 [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > > -- > 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 [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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