In a physical reality.? But once we assume mechanism, we cannot do that assumptions. Halting and non halting computations is a very solid notion which does not depend on the physical reality, nor of any choice of the universal complete theory that we presuppose. We still have to assume one Turing universal system, but both theology and physics are independent of which universal system we start with. I use usually either arithmetic, or the combinators or a universal diophantine polynomial. With mechanism, the physical laws are not fundamental, but are explained “Turing-thropically”, using the logics of self-reference of Gödel, Löb, Solovay. To test empirically the digital mechanist hypothesis (in the cognitive science) we have to compare the physics deducible by introspection by Turing machine, with the physics observed. Thanks to QM, it fits up to now. But we are light years aways from justifying string theory, or even classical physics. The goal is not to change physics, but to get the metaphysics right (with respect to that mechanist assumption and the mind-body problem). The notion of computation is the most solid epistemological notion, as with Church’s thesis, it admit a purely mathematical, even purely arithmetic, definition. Analysis and physics are ways the numbers see themselves when taking their first person indetermination in arithmetic into account. > is then most likely relevant to spacetime physics of quantum fields. If we > have a black hole of mass M it then has temperature T = 1/8πGM. Suppose this > sits in a spacetime with a background of the same temperature. We might be > tempted to say there is equilibrium, which is a sort of halted development. > However, it the black hole emits a photon by Hawking radiation of mass-energy > δm so M → M - δm it is evident its temperature increases. Conversely if it > absorbs a photon from the thermal background then M → M + δm and its > temperature decreases. I am not sure I understand this. > This will then put the black hole in a state where it is now more likely to > quantum evaporate or to grow unbounded by absorbing background photons. > > This might then be a situation of nonhalting, The problem of the existence of infinite computation in the physical universe is an open problem in arithmetic. Arithmetic contains all non halting computations, but it is unclear if the physical universe has to be finite or not. The first person indeterminacy suggests a priori many infinities, including continua, but the highly counter-intuitive nature of self-reference suggests to be cautious in drawing to rapidly some conclusion. With mechanism, a part of our past is determined by our (many) futures. > and with gravitation or quantum gravity the moduli space is nonHausdorff That could be interesting. The topological semantics of the theology (G and G*) are nonHausdorff too. Could be a coincidence, of course, as physics should be in the intensional variants of G*. > with orbits of gauge equivalent potentials or moduli that are not bounded. We > might then consider quantum gravitation as an arena where the quantum > computation of its states are nonhalting, or might they be entirely > uncomputable. The inability to isolate a qubit in a region smaller may simply > mean that no local observer can read the output of an ideal hyper-Turing > machine from an HM spacetime. OK, I think. That would make Mechanism wrong. That is testable, but the evidences favours mechanism. > >> >> The levels of confusion over this are enormous. It does not tell us that >> spacetime is somehow sliced and diced into briquets or pieces. > > I agree. Besides, this might depend heavily on the solution of the quantum > gravity problem. Loop gravity, as far as I understand it, does seem to impose > some granularity on space-time. Superstring do not, apparently. > > > > String theory does some other things that may not be right as well. The > compactification of spaces with dimensions in addition to 3-space plus time > has certain implications, which do not seem to be born out. I cannot really judge this. I can agree that this is a bit the ugly part of that theory (I mean the compactififed dimension), but that is not an argument, and taste can differ ... > > > > >> It does not tell us that quantum energy of some fields can't be far larger >> than the Planck energy, or equivalently the wavelength much smaller. > > OK. > > >> This would be analogous to a resonance state, and there is no reason there >> can't be such a thing in quantum gravity. The Planck scale would suggest >> this sort of state may decay into a sub-Planckian energy. Further, it is >> plausible that quantum gravity beyond what appears as a linearized weak >> field approximation similar to the QED of photon bunched pairs may only >> exist at most an order of magnitude larger than the Planck scale anyway. A >> holographic screen is then a sort of beam splitter at the quantum-classical >> divide. > > This is a bit less clear to me, due to my incompetence to be sure. If you > have some reference or link, but it is not urgent. I have not yet find to > study the Holographic principle of Susskind, bu I have followed informal > exposition given by him on some videos. Difficult subject, probably more so > for mathematical logician. > > Bruno > > > This last part involves some deep physics on how the holographic screen is in > entangled states with Hawking radiation. That is interesting. Note that with mechanism, we know "for sure” that the ultimate reality (independent of us the Löbian universal machine) has to be non dimensional (as arithmetic and elementary computer science is). Bruno > > LC > > -- > 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 > <mailto:everything-list+unsubscr...@googlegroups.com>. > To post to this group, send email to email@example.com > <mailto:firstname.lastname@example.org>. > Visit this group at https://groups.google.com/group/everything-list > <https://groups.google.com/group/everything-list>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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