Le 12-déc.-05, à 18:07, Tom ([EMAIL PROTECTED]) a écrit :

In response to Stathis' thought experiment, to speak of an experimentbeing "set up" in a certain way is to base probabilities on an"irrelevant" subset of the whole, at least if the multiversehypothesis is true. In the Plenitude, there are an additional 10^100copies still existing, when you say that 10^100 copies are beingshut-down. Talking about these additional 10^100 copies is just asconsistent as talking about the original 10^100 copies (even moreconsistent if you consider Bruno's statement about cul-de-sacs.In the Plenitude, everything washes out to zero. And Bruno, I wouldeven say that all consistent histories wash out to zero.

I am not sure why you say this.

Bruno, I've been following your posts about Kripke semantics and havedone the exercises, including the one about showing that you need asymmetrical accessibility relation to have LASE.

Nice !

However, my initial reaction still is that choosing a particular modallogic is scary to me, sending up red flags about hidden assumptionsthat are being made in the process. But I will continue to follow youas you present your case.

`Actually I do agree with you. But in the present case, that is with`

`comp as I defined it (or much weaker assumption really) we will not to`

`have to make a choice on the modal logics, they will be given by the`

`interview of the lobian machine. Precisely G (and G*) will appear to be`

`the complete and sound logic of the provable (and true)`

`self-referential statements made by a sound or self-referentially`

`correct machine. This is a consequence of a theorem in pure`

`mathematics: Solovay theorem.`

`Then, the translation of the UDA and in particular of the 1 and 3`

`notions will lead to the other modal logics we need, without us adding`

`more (hidden) assumptions than the comp one (or much weaker).`

Earlier Stathis wrote:Bruno: OK but with comp I have argued that OMs are not primitive butare "generated", in platonia, by the Universal Dovetailer. A 3- OM isjust an UD-accessible state, and the 1-OMs inherit relativeprobabilities from the computer science theoretical structuring of the3-OMs.Are OMs directly generated by the UD, or does the UD generate thephysical (apparently) universe, which leads to the evolution ofconscious beings, who then give rise to OMs?Stathis PapaioannouIt's interesting that symmetry (Bruno's requirement for LASE) has comeup lately, because Stathis' question seems to be what we are allwondering. That's the bottom line of multiverse theories: Where doesthe symmetry breaking come from?

`Actually comp put a big assymmetry at the start (the natural numbers:`

`0, 1, 2, 3, 4, ...), and my question for years was how to get the`

`symmetry which apparently lives at the bottom of physics (already`

`classical physics, still more with QM-without collapse).`

I maintain still that it can't come from the multiverse itself.

`But which "multiverse"? remember that the QM, or the existence of any`

`physical multiverse are not among the hypothesis. Indeed the UDA forces`

`us to justify completely the appearances of a "physical" multiverse.`

Even considering only consistent histories, there is no asymmetry tobe found.

`This astonishes me a little bit. The very notion of "history", it seems`

`to me, is assymetrical. But then I am not sure if you are talking about`

`the comp consistent extensions of some machine (the comp histories) or`

`the quantum histories of Everett, Hartle, and Co. ?`

I maintain that it needs to come from outside the multiverse, whichis something that we cannot explain.

`It certainly (with comp) needs to be explain from outside any notion of`

`"physical multiverse".`

`Then the truth-provability gap (capture by the modal logic G* \ G, that`

`is the set difference between the provable self-referential statements`

`and the true self-referential statements) will "explain" why we cannot`

`explain that something.`

I should perhaps make some summary. Bruno http://iridia.ulb.ac.be/~marchal/