Re: UDA Step 7

From: GŁnther Greindl <>
Date: Wed, 02 Apr 2008 20:16:24 +0200

Dear Bruno,

> Yes. The comp "intelligible matter" hypostases give the modal logic
> corresponding to quantum logic, except that I loose the necessitation
> rule.
> The significance of this remains to be seen of course.

Ok I get it. I will reread your papers :-) (too much new stuff in one

> In a nutshell, the restriction to the sigma_1 sentences *is* the
> translation of the comp hyp in the language of a Lobian machine.
> Why?
> Because you can characterize a Turing Universal Prover Machine by the
> fact that she can prove all true Sigma_1 sentences. So Turing
> Universality can be defined by the modal formula p -> []p, for p
> sigma_1. A lobian machine is not only universal, but "knows" that she
> is universal, i.e. she can prove all the formula p -> []p for p
> Sigma_1. Adding the axiom p -> []p to the logic G, gives the
> self-reference logic of the computationalist lobian machine. The
> Universal Dovetailer is equivalent to the set of true sigma_1 sentences
> together with their many proofs.
> This is explained at the end of most of my papers, but needs some
> amount of knowledge of recursion theory.

Ah OK; I am going to do some recursion theory this semester. (the Rogers
book :-)
Could you recommend something on modal logic?

> Hmmm... I would say that 3rd person white rabbit appear when there are
> too much universes with aberrant histories. Too much universes with too
> much talking white rabbits having clocks in their hands and saying "too
> late, too late ..."?

Yes that is what I meant.

>> but I think
>> they are also aware of first person white rabbit, as they discuss the
>> Boltzmann brain quite literally as a "brain" in some papers - which
>> just
>> oozes away after some time or immediately after "cogito ergo sum".
> I don't understand. (In general the first person is forgotten or
> assimilated to third person constructs like brain through some identity
> thesis, this cannot work by the Movie Graph argument or by Maudlin's
> Olympia: we have discuss this).

Now I don't understand; I am aware of Maudlin's Olympia, though not of
your movie graph argument.

How do you mean the first person is forgotten?


GŁnther Greindl
Department of Philosophy of Science
University of Vienna
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Received on Wed Apr 02 2008 - 14:17:01 PDT

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