Hi Stathis, I answer you, but it is at the same time a test, because most of my yesterday (sunday 22 october) posts seems not having been send successfully. (Some arrived at the archive, but not in my mail box, others nowhere, I will wait a whole and resend them: it was message for Peter and David).
Le 23-oct.-06, à 04:35, Stathis Papaioannou a écrit : >> Church thesis just assert that a universal turing machine can compute >> all computable functions from N to N. >> It relate a mathematical object with a human cognitive notion. It does >> not invoke physical machine at all. > > In a sense that is true, but a TM is still a model of what could > possibly be built > in a physical universe such as ours. Of course the model is still > valid irrespective > of the existence of a physical machine or indeed a physical universe, > but if you > abandon the idea of a physical universe there is no need to constrain > yourself to > models based on one. I am not sure why you say the TM model is based on what we can build in the physical universe. Both with comp and without, the physical universe is a priori far richer than a UTM. The UTM of Turing relies explicitly on an analysis of human capacity for computations. Post universal systems are based on analysis of mathematician psychology. > So I suppose the two questions I have (which you partly > answer below) are, having arrived at step 8 of the UDA could you go > back and > say that the UD is not really necessary but all the required > computations exist > eternally without any generating mechanism or program (after all, you > make this > assumption for the UD itself), or alternatively, could you have > started with step > 8 and eliminate the need for the UD in the argument at all? This is the way I proceed in "Conscience and Mechanism". I begin, by using the movie graph argument MGA, to show that consciousness cannot be attached to physical activities, and then I use the UD to explain that the comp-physics get the form of a measure on all computations. In my Lille thesis I do the opposite because the UDA is simpler than the MGA. It is not so important. UD is needed to justify and to make mathematically precise the ontic 3-observer moments. They correspond to its (the UD) accessible states. > >>> It seems that this is the computer you >>> have in mind to run the UD. >> >> Only for providing a decor for a story. This assumption is eliminated >> when we arrive (step eight of UDA-8) at the conclusion that universal >> digital machine cannot distinguish any "reality" from an arithmetical >> one. >> >> >>> That's OK and the argument works (assuming >>> comp etc.), but in Platonia you have access to hypercomputers of the >>> best >>> and fastest kind. >> >> Fastness is relative in Platonia. Universal machine can always been >> sped up on almost all their inputs (There is a theorem by Blum and >> Marquez to that effect). Then indeed there are the "angels" and >> hierachies of "non-comp" machine. A vast category of "angels" can be >> shown to have the same hypostases (so we cannot tested by empirical >> means if we are such angels). Then they are entities very closed to >> the >> "one", having stronger hypostases, i.e. you need to add axioms to G >> and >> G* (or V, V* with explicit comp) to get them. > > Of course I was joking when I said "best and fastest". In Platonia > there is > no actual time and everything is as fast and as perfect as you want it. OK. But of course there exist notion of relative time: a fast Fourier transform is faster than a slow Fourier transform, even in Platonia. Of course this can be said in term of number of steps in computations (no need to invoke time). 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 everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~----------~----~----~----~------~----~------~--~---
