On 19 May 2012, at 19:17, Stephen P. King wrote:

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On 5/19/2012 4:06 AM, Bruno Marchal wrote:Stephen,I presented an argument. Whatever you read, if it casts a doubt onthe validity of the argument, you have to use what you readto find the invalid step.If not, you act like so many papers pretending that cannabis is adangerous, but which are only speculation on plausibledanger, not proof.A proof, both in math and in applied math in some theoreticalframework does not depend on any further research, by construction.If you doubt about immaterialism, by reading on Markow (say), thenyou might find a way to use Markov against computationalism, or youmust make precise which step in the reasoning you are doubting andwhy, and this without doing interpretation or using philosophy.If not, you confuse science and philosophy, which is easy when thescientific method tackle a problem easily randed in philosophy, orat the intersection of philosophy and science.Now, I don't see why the work you mention has anything to do withthe immaterialism derived from comp. You might elaborate a lot.BrunoDear Bruno,I finally found a good and accessible paper that discusses mybone of contention. To quote from it:"A theorem proved by Markov on the non-classifiability ofthe 4-manifolds impliesthat, given some comprehensive specification for the topologyof a manifold (such asits triangulation, a la Regge calculus, or instructions forconstructing it via cuttingand gluing simpler spaces) there exists no generalalgorithm to decide whether themanifold is homeomorphic to some other manifold [l]. Theimpossibility of classifyingthe 4-manifolds is a well-known topological result, the proof ofwhich, however, maynot be well known in the physics community. It ispotentially a result of profoundphysical implications, as the universe certainly appears tobe a manifold of at leastfour dimensions." The reference to the proof by Markov is:Markov A. A. 1960 Proceedings of the International Congress ofMathematicians, Edinburgh 1958(edited by J. Todd Cambridge University Press, Cambridge) p 300The point of this is that if the relation between a pair of 4-manifolds is not related by a general algorithm, how then is itcoherent to say that our observed physical universe is the result ofgeneral algorithms?

`But comp explained why it has to be like that. The observable universe`

`cannot be the result of general algorithm, given that it results from`

`a first person plural indeterminacy on infinite set of possible`

`computations.`

`By "computation" I mean a set of states together with an universal`

`number relating them.`

`The only thing proved by Markov here is that the homeomorphism`

`relation is not Turing decidable. It suggests that 4-manifold +`

`homeomorphism is Turing universal (as proved for braids). Any`

`intensional identity, for any Turing complete system is as well not`

`Turing decidable. There is no general algorithm saying that two`

`programs compute the same functions, or even run the "same" computation.`

It is a well known result for logicians.

`You don't give a clue what it has to do with immateriality. To be`

`franc, I doubt that there is any.`

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 everything-list+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.