On Monday, March 9, 2020 at 4:57:24 AM UTC-5, Bruno Marchal wrote: > > > On 5 Mar 2020, at 12:42, ronaldheld <[email protected] <javascript:>> > wrote: > > Any comments, especially from Bruno, and the Physicalists? > > -- > 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] <javascript:>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/ff950ee5-b253-464e-b0aa-9eca73399b9c%40googlegroups.com > > <https://groups.google.com/d/msgid/everything-list/ff950ee5-b253-464e-b0aa-9eca73399b9c%40googlegroups.com?utm_medium=email&utm_source=footer> > . > <2003.01807.pdf> > > > > The paper is quite interesting, but I will have to deepen my understanding > of Black Hole (and GR) to better appreciate it. > > There are some preliminary point were “I disagree” (or the universal > machine disagree) but they might not be relevant, with respect to the > paper, but relevant to the plausible link you make between the paper and > physicalism. > > Typically, the first sentence of the paper is “physicalist”, which is not > astonishing in this context. Susskind says that the original Church-Turing > thesis may be regarded as a principle of physics (which it is not). > > This can be shown inconsistant with the mechanist assumption in Cognitive > Science (not in physics). Indeed, with mechanism, a priori, the physical > reality should be able to compute more than a Turing machine. The physical > reality can simulate “real” random oracle, for examples, and any physical > object requires the entire universal dovetailing to be determined. That > entails non cloning, and a priori much more computability abilities (random > oracle, “white rabbits”, infinite sum on infinitely histoiries, the full > set of true sigma_1 sentences, but also non computable Pi_1 truth > pertaining to the distribution of accessible states, etc. > That is so true, that Mechanism must explain the apparent computability of > nature from non computable subset of the arithmetical truth. So, here, > implicitly the paper relies on physicalism, without the awareness that > eventually the physical appearances have to be explained by the statistics > on all computations in arithmetic, not just the “quantum one”, and the > quantum must be extracted from the machine’s theory of consciousness (as I > did). So, normally, it can be expected that the (original) Church-Turing > thesis (which is one half of Mechanism) might imply the falsity of the > quantum Church-Turing thesis (due to Deutch, and I have to think how much > that is related to Susskind quantum-extended Church thesis). > > This concerns only the original Church Thesis and its impact on the > possible physics available to arithmetical machine, and as physics is not > yet entirely derived neither from Arithmetic, nor from observation (cf the > GR + QM problems), it is hard at this stage to see how much mechanism will > assess or diminish the validity of Susskind’s idea on the extended Quantum > and physical version of CT. > Yet, unlike the typical use of quantum mechanics to prevent an infinite > computation to be realised in the physical universe, which would need > digital state encodable below the Planck Era (and thus hardly usable by any > concrete observer), the idea of Susskind is more subtle, and involves a > notion of “complexity” related to the interior of Black-Hole. I would need > here to revise (to say the least) Finkelstein derivation of GR from a > finitist or discrete approach to Quantum Mechanics, which is still above my > head … (I mentioned the interesting book by Selesnick on it sometimes ago). > > So, just to be clear: > > CT = anything computable is computable by a Turing machine (or by a > combinator, or by Robinson Arithmetic, or by LISP, etc.). This has a priori > nothing to do with physics. > > I will note s-CT for Susskind Physicalist version of CT: any thing > physically computable is computable by a Turing machine. (The physical > reality does not compute more). This is an open problem to me. It is not > excluded that the physical reality which emerges from all computations in > arithmetic might have non Turing computable components. > > Then s-ECT is the thesis that anything computable *efficiently* (i.e. in > polynomial time) physically, by nature, is computable in polynomial time by > a Turing machine. This thesis is usually believed to be wrong, as Susskind > says, and indeed, if that was not wrong, we would not invest in quantum > computing. Most people today believes that factoring (large) number cannot > be done in polynomial time by a Turing machine. > > qECT (Susskind notation) is the (extended) thesis that says that if nature > can compute efficiently something then a quantum computer can compute it > efficiently. That is mainly what I call the Deustch Thesis. And as <I said, > I do think that CT (+ YD, i.e. mechanism) entails its plausible falsity. > > And Susskind abounds in that direction, and this without Mechanism, which > would make this into a yet another confirmation of Mechanism. > > With Mechanism, and assuming the existence of Black Hole, it should be > obvious that whatever happens in a black hole will not play a role in the > working of your brain. A good thing, as you will not have to ask to the > Doctor to emulate the interior of a black hole. But with mechanism, this > means that a black hole is full of "crazy virtual particles" doing > infinitely complex task, just because your state of mind is totally > independent of the”content of the black hole (without its boundary)". > > At first sight, Susskind seems convincing on this, but again, to be able > to asses this would require that I study much more the QM and GR of the > black hole. To compare with Mechanism, we have the rather complex task to > derive GR from QM and QM from arithmetic before, so this is a bit premature > (I still work hard to have a notion of space, although its shadow is there, > but requires the existence of large cardinal in set theory. (As I said, > with Mechanism, the ontology is extremely simple (Robinson arithmetic), but > the phenomenology is of unbounded complexity. > > So, very interesting but complex idea by Susskind, but it touches on > problem which are far from being treated with the mechanist hypothesis. If > I progress in my understating of Finkelstein, I might say more later. The > paper confirms that there is something in the holographic idea, and when > you compactify a universal dovetailing, you get a sort of similar > principle, given that the first person experience are determined only on > its “boundary”. > > Bruno >
>From the perspective of a physicist who knows some things about Gödel’s theorem and even Löb’s theorem I think in one sense you use language or metaphysics that is a bit outside of science. Terms such as physicalists are not used, and materialism sometimes comes up and it is not clear to me how this deviates from the term physicalist. The first of Gödel’s theorem comes in with looking at a list of observations of a quantum system, such as a list of probabilities on the abscissa and actual measurements on the ordinate. This can then be used to perform the Cantor diagonal trick, which flips the outcome, and this is then not predicable. The inability to predict the outcome of a particular measurement of a quantum system can then be expressed according to a Cantor diagonal argument. This then leads to a form of the incomputable nature of QM. This then leads to the observation that measurements in QM require that if one is to measure a spin in the z direction this means any prior knowledge of spin in the x direction is to be lost. In general relativity there are also event horizons that restrict knowledge one can have of the quantum state of a black hole. Jacobson showed how spacetime can be viewed from statistical mechanics as composed of a distribution of states. An event horizon is also a surface of reduced dimension that has quantum information. Raamsdonk also illustrated how spacetime can be looked at as due to large N-entanglement. So the loss of knowledge of a quantum spin in one direction in a measurement along another is in a general setting much the same as the red shifting of information from n event horizon that restricts access to information. This then suggests with the Cantor diagonalization that the relationship between stochasticity and its dual in determinism has an incomputable relationship between quantum and spacetime physics. For stochasticity a p = 1 in a convex set with a dual q = ∞ and 1/p + 1/q = 1 there is are associated L^2 systems for p = q = 2, or 1/p = 1/q = ½, which are relativity as a metric space and QM as a system of probabilities determined by the square of amplitudes. 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/68bf4530-5d14-493c-90c2-bc4d232bfb32%40googlegroups.com.
