On Sunday, May 28, 2017 at 12:24:32 PM UTC+10, Jason wrote: > > > > On Saturday, May 27, 2017, Russell Standish <li...@hpcoders.com.au > <javascript:>> wrote: > >> On Thu, May 25, 2017 at 06:30:07PM -0700, Pierz wrote: >> > Recently I've been studying a lot of history, and I've often thought >> about >> > how, according to special relativity, you can translate time into space >> and >> > vice versa, and therefore how from a different perspective we can think >> of >> > the past as distant in space rather than time: my childhood being 40 >> light >> > years away, rather than 40 years for instance. I can visualise my own >> body >> > as a sort of long, four dimensional tendril through spacetime, of which >> I >> > only ever see a three-dimensional cross-section. This is the block >> universe >> > idea of course. What occurred to me recently was that the past, in any >> > physical theory I know of, is "locked down". There is only a single >> history >> > consistent with the present (ignoring the microscopic ambiguities of >> > quantum interference effects), but the present is consistent with >> multiple >> > futures. >> >> This assumption is wrong. There are many histories (pasts) consistent >> with our present. If we don't know some fact about the past (eg >> T. Rex's colour), then pasts with different colours of T.Rexes are all >> compatible with our present. Only when we make a measurement that >> distinguishes between different facts about the past, do we eliminate >> some of those pasts from the compatibility list. >> >> There are, however, arrows of time - past and future are asymmetric, >> the future is more uncertain than the past. But I don't see how you >> can leverage that into support for the MWI. >> >> >> > > I agree, there are multiple pasts compatible with our future. Some if > these can't be ruled out with any possible measurements, like in the case > if the quantum erasure. >
To be truly compatible, they would need to unable to be distinguished by an observation even in theory - as you say like the quantum eraser. I acknowledged that when I said "ignoring the microscopic ambiguities of quantum interference effects". But that such interference effects can occur on a macroscopic scale, extending up to multiple dinosaur histories with different coloured T.Rexes - that is a huge leap. One single bit of physical information difference destroys quantum interference effects, so I seriously doubt that two universes with such different information that their dinosaurs are different colours could ever come to interfere with one another. > > That entropy increases does mean there are more futures than pasts. > > Regarding special relatively and collapse, I think the point is that two > observers in different reference frames can have different presents. Two > humans walking past each other on the sidewalk may have presents that > include the Andromeda Galaxy hours apart in time. (See "Andromeda > Paradox"). So if something on Earth collspses the wave everywhere and > instantly (in the present) which present is it collapsed in? > Well collapse really only happens at the time-space location that the measurement interaction occurs (if I believed in collapse!). I wouldn't say the collapse theories are *incompatible* with SR, because mathematically there is no problem - any paradox comes out in the wash. Conceptually though, it is certainly weird that the wave somehow "knows" to collapse everywhere at once, especially when "at once" doesn't have a single meaning, as you point out. > > I think this even more clearly shows the incompatibility between collapse > theories and special relatively, beyond just pointing to the FTL influences > as violations; this shows now we have to somehow use an objective reference > frame which relatively tells us does not exist. And this leads to collapse > events happening in different times/places for different observers, even > ones walking past each other on a sidewalk. > > Jason > > > > >> >> -- >> >> >> ---------------------------------------------------------------------------- >> 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. >> > -- 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.
