Subject: "That would kill my idea"
Date: Thu, 03 Jul 2003 14:50:02 +0300 From: Dimi Chakalov <dchakalov@surfeu.at> To: H Dieter Zeh <zeh@urz.uniheidelberg.de> CC: William G Unruh <unruh@physics.ubc.ca>, Rafael A Porto <rafael@fisica.edu.uy>, Rodolfo Gambini <rgambini@fisica.edu.uy>, Jorge Pullin <pullin@rouge.phys.lsu.edu>, Don N Page <don@phys.ualberta.ca>, Carlos Barcelo <carlos.barcelo@port.ac.uk>, Matt Visser <matt.visser@mcs.vuw.ac.nz>, Adam Helfer <adam@math.missouri.edu>, Julian Barbour <jbarbour@online.rednet.co.uk>, Joy Christian <joy.christian@wolfson.ox.ac.uk>, George Ellis <ellis@maths.uct.ac.za>, Claus Kiefer <kiefer@thp.unikoeln.de> Dear Dieter, May I ask a question. In your "The Wave Function: It or Bit?" [Ref. 1], you wrote: "Claus Kiefer and I have been discussing the problem of timelessness with Julian Barbour (who wrote a popular book [39] about it) since the mideighties. Although we agree with him that time can only have emerged as an approximate concept from a fundamental timeless quantum world that is described by the WheelerDeWitt equation, our initial approach and even our present understandings differ. While Barbour regards a classical generalrelativistic world as timeless, Kiefer and I prefer the interpretation that timelessness is a specific quantum aspect (since there are not even parametrizable trajectories in quantum theory). In classical general relativity, only absolute time (a preferred time parameter) is missing, while the concept of onedimensional successions of states remains valid." Let me pin down the latest bit, "while the concept of onedimensional successions of states remains valid." Julian Barbour explained what would kill his idea: "I think that if the collapse of the wave function could be demonstrated to be a real physical phenomenon, that would be a true demonstration of something one might call transience" ("The End of Time", London: Phoenix, 2000, p. 359). I'm wondering, what would kill your belief that "the concept of onedimensional successions of states remains valid"? Please see the problem of 3D space at http://members.aon.at/chakalov/Nature.html#NB I will keep your reply private and confidential. BTW I support your conjecture that "the truly subjective observer system should be related to spacetime points" [Ref. 2], with some minor additions at http://members.aon.at/chakalov/Zurek.html#note As to the phenomenon of transience, I believe can prove Julian wrong with his own brain, http://members.aon.at/chakalov/Vecchi.html Only we don't have "collapse" there. More at http://members.aon.at/chakalov/Planat.html Needless to say, my hypothesis is also falsifiable, and I can happily put my cards on the table: If you or any of your colleagues can prove that there is 3D space in classical general relativity, I will be wrong. "That would kill my idea" (Julian Barbour, op. cit., p. 358). Please see my email of Tue, 18 Feb 2003 11:42:52 +0200 (printed below). Regards, Dimi
References [Ref. 1] H. Dieter Zeh, The Wave Function:
It or Bit?
Draft of invited chapter for "Science and Ultimate Reality" (J.D. Barrow, P.C.W. Davies, and C.L. Harper Jr., edts., Cambridge UP, 2004). Sec. 3, "The Reality of Superpositions": "the physical
state is *ou topos* (at no place), although it is not utopic according
to quantum theory."
[Ref. 2] H. Dieter Zeh, Quantum Theory
and Time Asymmetry,
Reproduced from FOUNDATIONS OF PHYSICS Vol. 9, pp. 803818 (1979) (with minor corrections and reformulations) "We also know empirically that the observer system is
spatially bounded (although we cannot give its precise boundaries), and
that consciousness changes with time. If consciousness is in fact defined
(and different) at every moment of time, it should also be related to points
in space: the truly subjective observer system should be related to spacetime
points [36]. (...) One would not even be in conflict with empirical evidence
when assuming that every spacetime point carries consciousness: we can
only communicate with some of them, and with other brains only as a whole,
in a nontrivial manner."
On Tue, 18 Feb 2003 11:42:52 +0200, Dimi Chakalov wrote:
====== Subject: Re: "That would kill my idea"
P.S. Regarding my preceding email of Thu, 03 Jul 2003 14:50:02 +0300: I elaborated on the argument against 3D space in classical GR at http://members.aon.at/chakalov/Zeh.html#note Your critical comments will be highly appreciated. Please don't hesitate! D.C. ====== Note: The argument
against 3D space in classical GR, as stated above,
begins with a simple introduction at I will elaborate on it below. Let me first stress that what I have in mind is quantum gravity. I believe there are at least two unresolved tasks. One is to suggest a precise reconstruction of a classical spacetime from nonlocal diffeomorphisminvariant observables. Not "approximately", as stated by Steve Carlip. The other task is to free the reconstructed classical spacetime from all pathologies of the classical spacetime manifold (cf. Ioannis Raptis' grqc/0110064, Sec. 2. (I believe the reconstructed classical spacetime should be cast on a nontrivial manifold that is both continual and discrete, such that we could "have our cake and eat it": a perfect continuum in the local mode of spacetime, and a "discrete" lattice in the global mode of spacetime. Of course, this is just a suggestion and I could be wrong.) Let's see what is the problem with 3D space. R. Parentani mentioned that the space should disappear as well due to the full reparametrization invariance of general relativity (see grqc/9710130). Fine, but what does that mean? If the phrase "time is gone" means that we can't say 'which happened first' in a global fashion (no preferred foliation), what would be the meaning of "space is gone"? Strangely enough, in each and every case of "local" unphysical "time", after Butterfield & Isham, we have an invariant, truly perennial (Karel Kuchar) 3D space that wraps each and every point from the unphysical "time" in classical GR. I smell a rat here. The intrinsic property of 3D space is that we can draw a sphere around a point 'now', such that there will be a set of points inside the surface of the sphere, and another set of points outside it. This is what the 3D space does. However, once we lose the time, we should lose the 3D space as well. Then we can recover it, along with time, from the nonlocal diffeomorphisminvariant observables (cf. S. Carlip above). All we need is to extend the Diff(M)invariance by including a new symmetry pertaining to transformations in 3D space. I've written about this putative 'space invariance' here (instructions on how to catch a lion in Sahara). If I'm on the right track, I will be happy to elaborate more. With math. So, is there a 3D space in classical GR? Isn't it an unjustified perennial entity which runs against the very spirit of the theory of relativity? A penny for your thoughts!
