On Sunday, May 28, 2017 at 12:24:32 PM UTC+10, Jason wrote: > > > > On Saturday, May 27, 2017, Russell Standish <[email protected] > <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 [email protected] >> 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 [email protected]. >> To post to this group, send email to [email protected]. >> 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
