On 03 Jul 2012, at 16:33, Jason Resch wrote:

On Tue, Jul 3, 2012 at 8:39 AM, Bruno Marchal <marc...@ulb.ac.be>wrote:On 02 Jul 2012, at 23:09, Jason Resch wrote: To summarize our conversation up to this point:BM: Do you really not see any difference between tables and chairsand people and numbers,JR: Chairs and people are also mathematical objects, just reallycomplex ones with a large information content. This is thenecessary conclusion of anyone who believes physical laws aremathematical.BM: No, it's a necessary conclusion of anyone who cannot distinguisha description from the thing described.JR: I think the identity of indiscernibles applies: If nodistinction can ever be made (by observers within a mathematicaluniverse and observers within a physical universe) then there is nodistinction. You are using "physical" as an honorific, but it addsno information.BM: I can point to a chair and say "This!"JR: Yes, but how do you know you are pointing to a "physical chair",rather than a "mathematical chair"?BM: I know I'm pointing at a chair. I don't know what at'mathematical chair' is. Can you point out how it is different froma chair?I think we both agree that if the universe follows mathematicallaws, then observers can make no distinction between whether theyexist in a platonically existing mathematical object, or a physicaluniverse. If you agree with this, then there is no fundamentalontological difference between chairs, people, and numbers, that Ican see.Comp allows a big flexibility for the initial basic reality. If wechoose the natural numbers, then people and chair must be explainedfrom them, and usually will not be numbers.I agree that chairs, people != numbers, but I think they exist inthe same way numbers exist.

In which theory? What is a chair?

Facing the question: is the universe a mathematical object, or aphysical one, we must evaluate the two candidate theories as wewould any other.With comp, the "universe" is neither primitively physical, norprimitive mathematical. It is a mental object, or a theologicalobject. It exist as an object of thought in the mind of believingmachines (relative numbers).I assume the comp hypothesis, all experiences are the results ofcomputations.

`This is ambiguous, as computation of unction gives results. I guess`

`you mean that consciousness can be related to computation. (The nature`

`of that relation is different than we usually think when we abandon`

`the physical supervenience thesis).`

What I mean by a mathematical universe is any mathematical objectthat implements the computations necessary to contain observers.Any given observer, of course, may exist in an infinite number ofsuch objects (universes) and there is no one universe the observercan rightfully be said to belong to.

`Yes there is one. In fact many. In fact all universal systems can do.`

`I use the tiny universal fragment of arithmetic to fix the thing.`

Does one theory explain more, does one make fewer assumptions, etc. That is the right attitude.The existence of the physical universe does not explain theexistence of mathematical objects, but the converse is true.Yes. And not only with comp, but with most of his natural weakening.If we have to explain the existence of both: mathematical objects,and the physical universe, the simpler theory is that mathematicalobjects exist, as it also explains the appearance of the physicalworld. If one accepts mathematical realism, then postulate thephysical world as some other kind of thing, in addition to itsmathematical incarnation, is pure redundancy.OK.I think that the idea of a primitive universe is a dogma. Of courseit is only a superfluous (redundant with comp) hypothesis.Now the idea that the physical universe is "only" a mathematicalobject among others is false too. It is a mental phenomenon as livedby internal creature and provably made non mathematical from theirpoints of view. The relation between mind and matter, but alsobetween physics and the mathematical reality are more subtle than asimple mathematicalist shift. The physical reality "needs" theconsciousness of *all* (universal, LĂ¶bian) machines to exist in somesense, even if locally, large part of that physical reality will beindependent of the local conscious creatures embedded in it. Physicsis really the result of an epitemological process, which exists bythe nature of the arithmetical relations.What do you think about the existence of mathematical objects thatdo not contain observers?

`They exist like the object of the term of my (first order`

`specification) of my initial universal theory.`

With arithmetic, it means that they exist like the numbers exist.

Is their type of existence somehow different from those that can/docontain observers?

`They are not different. Non universal numbers exists in the same sense`

`that universal numbers. Note that in that theory infinite set simply`

`does not exist, except in the (fertile) imagination of the universal`

`numbers.`

`With comp, the idea that there is anything more than non negative`

`integers is just absolutely undecidable.`

`The more interesting existence appears in the dreams, theologies, and`

`truth quests of the numbers trying to understand themselves. Even`

`Cantor paradise is not enough big to describe the internal realms.`

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.