On Jul 20, 2:43 pm, Bruno Marchal <[email protected]> wrote: > On 20 Jul 2011, at 15:21, 1Z wrote: > > > > > > > On Jul 8, 5:53 pm, Bruno Marchal <[email protected]> wrote: > >> On 08 Jul 2011, at 02:35, meekerdb wrote: > > >>> On 7/7/2011 4:59 PM, Russell Standish wrote: > >>>> On Wed, Jul 06, 2011 at 10:12:45PM -0700, meekerdb wrote: > > >>>>>> One that happens to be incompatible with > >>>>>> theory that our minds are computer programs. > > >>>>> Can you explain that? It seems to be Bruno's central claim, but > >>>>> so > >>>>> far as I can see he only tries to prove that a physical reality is > >>>>> otiose. > > >>>>> Brent > > >>>> Here's my take on it. I guess you read the version I wrote 6 years > >>>> ago > >>>> in ToN. > > >>>> Once you allow the existence of a universal dovetailer, we are far > >>>> more likely to be running on the dovetailer (which is a simple > >>>> program) than on a much more complicated program (such as > >>>> simulating > >>>> the universe as we currently see it). Under COMP, the dovetailer is > >>>> capable of generating all possible experiences (which is why it is > >>>> universal). Therefore, everything we call physics (electrons, > >>>> quarks, > >>>> electromagnetic fields, etc) is phenomena caused by the running of > >>>> the > >>>> dovetailer. By Church-Turing thesis, the dovetailer could be > >>>> running > >>>> on anything capable of supporting universal computation. To use > >>>> Kantian terminology, what the dovetailer runs on is the noumenon, > >>>> unknowable reality, which need have no connection which the > >>>> phenomenon > >>>> we observe. In fact with the CT-thesis, we cannot even know which > >>>> noumenon we're running on, in the case there may be more than > >>>> one. We > >>>> might just as well be running on some demigod's child's > >>>> playstation, > >>>> as running on Platonic arithmetic. It is in principle unknowable, > >>>> even > >>>> by any putative omniscient God - there is simply no matter of fact > >>>> there to know. > > >>>> So ultimately, this is why Bruno eliminates the concrete > >>>> dovetailer, > >>>> in the manner of Laplace eliminating God "Sire, je n'ai besoin de > >>>> cet > >>>> hypothese". > > >>>> Anyway, Bruno will no doubt correct any mistaken conceptions > >>>> here :). > > >>>> Cheers > > >>> That's what I thought he said. But I see no reason to suppose a UD > >>> is running, much less running without physics. We don't know of any > >>> computation that occurs immaterially. > > >> I'm afraid this is not true. Some people even argue that computation > >> does not exist, the physical world only approximate them, according > >> to > >> them. > >> I have not yet seen a physical definition of computation > > > How about "a series of causally connected states which process > > information" > > Can you give me a physical definition of the terms "series", "causal", > "connected, "states", "process", and "information"? > And I am very demanding: I would like an axiomatic definition.
There is no reason you should be entitled to one. Physicsts happily define time as what clocks measure. > In absence of such a definition, you are just describing an > implementation of a computation in what you assume, implicitly, to be > a natural universal system. > > > > > > >> , except by > >> natural phenomenon emulating a mathematical computation. Computer and > >> computations have been discovered by mathematicians, and there many > >> equivalent definition of the concept, but only if we accept Church > >> thesis. > > >> Now if you accept the idea that the propositions like "if x divides 4 > >> then x divides 8", or "there is an infinity of twin primes" are true > >> or false independently of you, then arithmetical truth makes *all* > >> the > >> propositions about all computations true or false independently of > >> you. The root of why it is so is Gödel arithmetization of the syntax > >> of arithmetic (or Principia). To be a piece of a computation is > >> arithmetical, even if intensional (can depend on the *existence* of > >> coding, but the coding is entirely arithmetical itself. > > >> In short, I can prove to you that there is computations in elementary > >> arithmetical truth, but you have to speculate on many things to claim > >> that there are physical computations. Locally, typing on this > >> computer, makes me OK with the idea that the physical reality > >> emulates > >> computations, and that makes the white rabbit problems even more > >> complex, but then we have not the choice, given the assumption. > > >>> So I assumed I didn't understand Bruno's argument correctly. > > >> You seem to have a difficulty to see that elementary arithmetic "run" > >> the UD, not in time and space, but in the arithmetical truth. > > > He should. Truth is not existence. > > What is "existence"? This. [[points in all directions]]. >If you refer to physics, then you are begging the > question, or you are just assuming that we are not machine. > > Bruno > > > > > > >> Even the > >> tiny Robinson arithmetic proves all the propositions of the form it > >> exist i, j, s such that phi_i(j)^s is the s first step of the > >> computation of phi_i(j). And RA gives already all the proves, and so > >> already define a UD, which works is entirely made true by the > >> arithmetical reality, which I hope you can imagine as being not > >> dependent of us, the human, nor the alien, nor the Löbian machines > >> themselves (RA+ the inductions). > > >> The arithmetization is not entirely obvious. It uses the Chinese > >> theorem on remainders, you need Bezout theorem, and all in all it is > >> like implementing a very high level programming languages in a very > >> low level "machine language", with very few instructions. > >> Matiyasevitch has deeply extended that result, by making it possible > >> to construct a creative set (a universal machine) as the set of non > >> negative integers of a degree four diophantine equation. This has the > >> consequence that you can verify the presence (but not necessarily the > >> absence) of *any* state in the UD (like the galactic state described > >> above) in less that 100 additions and multiplications. That is weird! > >> A degree 4 diophantine polynomial can emulate any arbitrary growing > >> functions from N to N, and even from Q to Q. So if you agree that a > >> natural numbers is solution or not, of a diophantine polynomial, > >> independently of you, then all digital computations are realized, or > >> not, independently of you, me, or the physical universe. > > >> Bruno > > >>http://iridia.ulb.ac.be/~marchal/ > > > -- > > You received this message because you are subscribed to the Google > > Groups "Everything List" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected] > > . > > For more options, visit this group > > athttp://groups.google.com/group/everything-list?hl=en > > . > > http://iridia.ulb.ac.be/~marchal/ -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.
