Thanks Bruno

I want to have a good think about your answers and also the eighth
step in your paper.  I think it is the most difficult for me and yet I
sense its somehow. Schmidhuber assumes a great programmer runs the UD
but you effectively dispense with him. If a universal turing machine
necessarilly exists platonically which is capable of running UD's that
can simulate our minds then our experience of reality follows. Yet I
still feel that somehow this will be confusing the map of the
territory with the "reality", the equations of physics with the
physically real.

Best wishes


On Dec 23, 2:15 pm, Bruno Marchal <> wrote:
> Hi Nick,
> On 23 Dec 2009, at 01:55, Nick Prince wrote:
> > My background is in mathematical physics but I am trying to read up a
> > bit of this new stuff as I go along.  Thank you for being patient with
> > me.
> > However, I think you have confirmed some things - let me know if any
> > of these is fundamentally wrong.
> > I want to put aside the platonic arithmetical UD for the moment but
> > will come back to that.
> > Just supposing that there is as yet NO UD operating.  Comp says it is
> > possible to build a "concrete" one and in step 7 of your paper you say
> > that the UD could provide infinitely  many possible consistent
> > extensions of me.  (I am thinking of descriptions of simulated worlds
> > with me in them  as  bit strings)  I quote you from the sane paper:
> > "Then, it follows from the six preceding steps that it will generate
> > all possible Turing machine states, infinitely often (why?), which (by
> > comp) includes all your virtual reconstitutions corresponding to
> > (hopefully) consistent extensions of yourself, in all possible
> > (locally) emulable environments or computational histories. And this,
> > with comp, even in the case you consider that your ‘‘generalised
> > brain’’ (the ‘‘whatever’’ which is needed to be emulated by a  DU
> > digital body/brain to survive) is the whole Milky Way galaxy. And we
> > don’t need any Science Fiction like devices to make this concrete, if
> > we make exception of the robust universe."
> > Actually the kind of "teleportation" I am interested in, for reasons
> > as you will see is the usual simple one which takes us from moment to
> > moment.  I am being teleported into the next observer moment all the
> > time ( if this is because I'm already being computed by a UD then as I
> > say lets just ignore this possibility for now as you did in your
> > paper).  If someone is blown to bits, then we have lost the chance to
> > make a decent copy of them.  However, Once the “concrete” UD is run
> > then it  computes all possible futures for all possible virtual
> > extensions. Then there will be  an (infinitely many) extension(s) for
> > the blown to bits person.  The blowing to bits is just the equivalent
> > of the annhiallation part of your earlier steps.  So here we have the
> > basic quantum immortality thing coming in again.
> OK. TO be sure it is the "older" comp immortality, and it is an open  
> problem if the quantum interference and immortality *is* a result of  
> the comp interference and immortality. It looks like that, and up to  
> now the math confirms formally the resemblance.
> > However, if  it
> > takes the UD a long time to generate sufficient extensions then the
> > delay will be considerable before the blown to bits man continues
> > consciousness - although to him it will seem instantaneous. From 3d
> > person, well - they see the delay.
> Yes. (would they live long enough)
> > Now is the interesting bit.  Because this future UD creates all
> > possible extensions of all possible states of the blown to bits man
> > then what’s to stop him finding continuation with a consistent
> > extension prior to the blowing up!
> Sure. (that happens all the time, and that's why we have to justify  
> the apparent stable laws from that).
> > In other words every observer
> > moment of his life (not just the one just before being blown up - but
> > any  of them) could just as easily be followed by a suitable one in
> > the virtual UD rather than one in the initial run of the universe.
> Absolutely. Would a real *singular* concrete material universe exist,  
> the probability to stay in that universe is zero.
> > In
> > conclusion,  from our ist person point of view we do not know whether
> > our next observer moment will occur in the “real” universe or in a
> > simulated one- this is 1-indeterminacy again.  If the UD can simulate
> > all possible observer moments then it will have those associated with
> > our very first sense of consciousness and hence we will have very
> > quickly slipped, without knowing it, into the UD’s virtual world.  We
> > never noticed any delay of course but there may have been a huge time
> > difference assuming Russell’s time postulate has meaning here!
> It has meaning, because it is neither physical time nor subjective  
> time, but just the natural numbers with the successor operation, or  
> the number of steps taken by the UD to reach the computational states.  
> And the step 8 explains why, even if a real physical time exists, it  
> just cannot compete with the UD "time".  It is no more than 0, 1, 2,  
> 3, ... or a set having a computable bijection with N.
> > Hence if a UD is possible,
> Well, the mathematical existence of the UD is a logical consequence of  
> Church thesis + Turing's theorem in computer science.
> There is number U such that for all x and y, phi_U(<x, y>) = phi_x(y).  
> U can emulate x on y.
> Once you can emulate all x, you can dovetail on all emulations  
> possible, including those with oracles in some rings.
> > then only the first observer moment(s) -or
> > fraction of our conscious lives - were ever lived in a “basic/real”
> > universe at all.  The rest is all simulation.  The very existence of a
> > UD implies that we are in a simulation as Nick Bostrom has suggested.
> Hmm... OK. To be precise, we belong to the infinities of computations  
> which differ below our level of substitution, and which are similar  
> above. This makes the apparent physical universe a priori NOT Turing  
> emulable, or not entirely Turing emulable. But here too, QM confirms  
> this: we cannot emulate with a Turing machine a beam of electrons all  
> prepared  in the state "up+down" going through an up/down measuring  
> apparatus, (without emulating the couple "observer + electron", but  
> then we have to classically emulate all the "parallel worlds").
> > If they exist platonically then it's all simulation and
> > computationalism must be necessary rather than contingent.
> OK. And some people are already convinced at that stage. But from a  
> logical point of view, a materialist could argue that the seven step  
> just shows that if comp is true, then the material universe is just  
> not enough big, or not enough robust to implement the running of the  
> UD. UDA would just show that materialism would imply our universe is  
> "small".
> The 8th step has two purposes:
> - one is showing that the very idea of linking consciousness to  
> physical activity is a non sense (despite the strong appeal for such  
> an idea, even through comp at first sight),
> - and the second is to prevent the above move toward a small universe.  
> It shows that with comp, we have to link consciousness, not to  
> material physical activity, nor even to any singular universal machine  
> computation, but to an infinity of computations, and we have to  
> understand that by "computation" we don't mean anything physical. A  
> computation is the doing of any universal machine: it is defined by  
> the "pure" additive-multiplicative relations between positive  
> integers---- or by anything recursively equivalent (as defined in  
> theoretical computer science), like the "pure" abstractive-applicative  
> relations between the SK-combinators.
> > It's a very fumbling line of thinking but it helps me to learn about
> > things as I go along.
> Cool. Ask any questions. Best,
> Bruno
> > On Dec 22, 6:41 pm, Bruno Marchal <> wrote:
> >> On 22 Dec 2009, at 18:48, Nick P wrote:
> >>>>> Hence by it generating all possible emulations of
> >>>>> stages of my life) that I could just as easily experience for my
> >>>>> next
> >>>>> OM as opposed to the one i would expect to experience on the  
> >>>>> current
> >>>>> wetware (or whateverware I'm running on if we are in fact already
> >>>>> software constructs in a simulation).
> >>>> This is weird. From some "absolute", non machine accessible view
> >>>> point, you can expect anything. Perhaps.
> >>> Assuming that comp is true, then I am not sure why you think it is
> >>> weird.  Perhaps I have not explained myself very well.  First of all
> >>> please check that my understanding of computationalism is correct.  
> >>> By
> >>> comp I mean (loosly)that I am assuming that any conscious being  
> >>> can be
> >>> simulated on some form of computer.  Currently my consciousness is
> >>> running on the substrate provided by my brain (hardware).  If the
> >>> underlying reality is a much more fundamental (unknown) substrate  
> >>> then
> >>> fine because this shouldn’t invalidate what I’m saying.  Now If I  
> >>> want
> >>> to be teleported from Brussels  to Moskow then sufficient  
> >>> information
> >>> must be coded for my reconstitution later on. This may or may not be
> >>> possible because it may turn out that the accessing of my final  
> >>> state
> >>> in Brussels  destroys my brain before the detailed brain state was
> >>> properly copied.  Worse still, suppose someone loses whatever coded
> >>> data they did have of me such that the reconstitution becomes
> >>> impossible.  What I am trying to say is that if comp is true then at
> >>> least I can be confident that some consistent extension of me could
> >>> exist in the future provided the robust physical universe you  
> >>> speak of
> >>> exists such that a suitable UD can actually be built.
> >> OK. (and then step 8 explains why the initial universe is no more
> >> useful, the arithmetical UD is enough).
> >> Also, it is perhaps always one next  1-observer moment, but also
> >> always an infinity of 3-observer moments. The UD is terribly
> >> redundant, and anything it does, it will repeat it infinitely  
> >> often. A
> >> compactification of it looks really like the border of the Mandelbrot
> >> set. The closer you look, the more complex it appears.
> >>
> >>> Once built then
> >>> there would exist at least one consistent extension of me (including
> >>> the milky way if this  level of entanglement is to be necessary to
> >>> adequately ensure this is the most probable next state of my
> >>> consciousness) in the UD which will enable me to experience my next
> ...
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