On Mon, Nov 11, 2019 at 8:18 PM Bruno Marchal <marc...@ulb.ac.be> wrote:
> On 10 Nov 2019, at 22:24, Bruce Kellett <bhkellet...@gmail.com> wrote: > > On Sun, Nov 10, 2019 at 11:22 PM Bruno Marchal <marc...@ulb.ac.be> wrote: > >> On 7 Nov 2019, at 22:58, Bruce Kellett <bhkellet...@gmail.com> wrote: >> >> On Fri, Nov 8, 2019 at 8:53 AM 'Brent Meeker' via Everything List < >> everything-list@googlegroups.com> wrote: >> >>> ISTM that creates problem for defining a point where one of the >>> probabilities becomes actualized. MWI tries to avoid this by supposing >>> that all probabilities are "actualized" in the sense of becoming orthogonal >>> subspaces. There are some problems with this too, but I see the attraction. >>> >> >> You can always find problems with any approach. What I particularly >> dislike about MW advocates (like Sean Carroll) is that they are dishonest >> about the number of assumptions they have to make to get the SWE to "fly". >> Particularly over the preferred basis problem and Born rule. Zurek comes >> closer, and he effectively dismisses the "other branches" as a convenient >> fiction. If these other branches play no effective role in explaining our >> experience, then why have them there? >> >> >> How could some terms in a wave expansion disappear without assuming some >> non unitary collapse of some sort? >> > > I did not say that they disappeared: merely that they do not play any role > in explaining our experience. > > > Then you agree with the, or some, form of the Many-Histories/World theory. > > If you can point to any such role, then fine. But I doubt that you can do > this. > > > That is the whole point of realism. To believe in things despite we can > not access to them. The belief that reality is bigger than the reality we > can personally observe. > That is not scientific realism -- that is metaphysical mysticism. > > >> There is no preferred basis, only personal basis to be able to interact >> locally in between us. >> > > Again you appear to ignore the primary role of science is in explaining > our experience. In our experience, there most certainly is a preferred > basis -- the world around us has not dissolved into the "mush" that > Schroedinger feared so much. If there is only a "personal basis", explain > to me why your personal basis does not include superpositions of live and > dead cats. > > > For exactly the same reason that when I am duplicated in Washington and > Moscow, I don’t feel personally to be in both cities at once. > So you are in the Washington/Moscow basis -- not the( W+/- M) basis. That is a preferred basis. > The linearity of the evolution of the wave + the linearity of the tensor > product entails that if a robot observe a cat in the state a + d, and this > with a ad-measuring device, he ends up into a robot observing the evolution > of a cat which is alive, and a robot observing the evolution of a cat which > is dead. > That is exactly the definition of a preferred basis -- which you appear to want to deny even exists. > Once we have a body, evolution has chosen the “preferred base”, but it > does not play a fundamental role in the fundamental equation. > Evolution has precisely nothing to do with it. The preferred basis is determined by quantum Darwinism acting on the normal physical interactions between quantum objects. Being human or sentient is totally irrelevant.. The preferred basis plays a fundamental role in the explanation of the world as we perceive it -- we do not directly perceive Hilbert space. And explaining our experience is the aim of science -- other things fall into the realm of metaphysics, which is not science. Bruce We need some base to have a perspective, like in Mechanist philosophy of > mind we need some universal machinery to be able to talk on all of them. > > Bruno > -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLS3Q0a0QJFNiv6NCh2zSrUxjzkTi5enj5u2o920XfMTbg%40mail.gmail.com.
