On Sat, Oct 29, 2022 at 11:37 AM Brent Meeker <[email protected]> wrote:
> > On 10/28/2022 5:28 PM, Bruce Kellett wrote: > > On Sat, Oct 29, 2022 at 10:54 AM Brent Meeker <[email protected]> > wrote: > >> >> On 10/28/2022 4:38 PM, Bruce Kellett wrote: >> >> On Sat, Oct 29, 2022 at 10:27 AM Brent Meeker <[email protected]> >> wrote: >> >>> >>> On 10/28/2022 3:06 PM, Bruce Kellett wrote: >>> >>> >>> Simply saying that QM as traditionally formulated considers measurement >>>> as a special process that os irreversible, doesn't cut it, because >>>> measurement is then not treated in terms of the fundamental dynamics >>>> of >>>> the theory, it is put in in an ad hoc way. >>>> >>> >>> Lots of things are put into physics in an ad hoc way. The Born rule is a >>> prime example -- it is just >>> imposed on the quantum wave function in an ad hoc way -- it cannot be >>> derived from the fundamental theory. >>> >>> >>> But by Gleason's theorem it's the only consistent way to put a >>> probability measure on Hilbert space. >>> >> >> Who said we need a probability measure? >> >> >> Because we observe that the same initial condition results in different >> later conditions, but with predictable probability distributions. >> > > That is what is known as an ad hoc adjustment of the theory -- anything > that is required for the theory to agree with observation. Let's face it, > all of physics is ad hoc! > >> That is as ad hoc as anything else; besides, unitary QM does not allow >> for a probabilistic interpretation. >> >> >> Not if you insist that all evolution is unitary, but that's why Born >> added the projection postulate to connect the unitary evolution to >> observation. >> > > But Saibal and his ilk are insisting that all physics is unitary. That is > why the addition of probability (and the Born Rule) is just an ad hoc > adjustment so that their theory agrees with observation. Gleason's theorem > does not change this fact. > > > It's not "ad hoc" when it's part of a theory that applies to everything. > That is just an arbitrary stipulation. > Without the projection postulate and the probability interpretation how > would we compare QM to experimental data? > We couldn't, so we would have to conclude that the theory was useless. That is why we add ad hoc postulates.....to compare to experiment. Bruce -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLRDm_jadtv_G-XK8-PDfC3c5FpexZhTAzSYQaLR-TQEoQ%40mail.gmail.com.
