Re: Boltzmann Brains rule out any theory?
On 06 Feb 2017, at 18:12, Stathis Papaioannou wrote: On Mon., 6 Feb. 2017 at 11:06 pm, Ronald Held wrote: Why Boltzmann Brains Are Bad Authors: Sean M. Carroll Comments: 27 pages. Invited submission to a volume on Current Controversies in Philosophy of Science, eds. Shamik Dasgupta and Brad Weslake Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); History and Philosophy of Physics (physics.hist-ph) Some modern cosmological models predict the appearance of Boltzmann Brains: observers who randomly fluctuate out of a thermal bath rather than naturally evolving from a low-entropy Big Bang. A theory in which most observers are of the Boltzmann Brain type is generally thought to be unacceptable, although opinions differ. I argue that such theories are indeed unacceptable: the real problem is with fluctuations into observers who are locally identical to ordinary observers, and their existence cannot be swept under the rug by a choice of probability distributions over observers. The issue is not that the existence of such observers is ruled out by data, but that the theories that predict them are cognitively unstable: they cannot simultaneously be true and justifiably believed. -- Here is the link: https://arxiv.org/pdf/1702.00850.pdf Everything I've ever seen written about Boltzmann Brains takes the position that they are obviously absurd. But here's another view: Boltzmann Brains would give rise to every possible thought - every possible observer moment. This is equivalent to the situation whereby every possible observer moment exists necessarily as a Platonic entity, without the need for a separate physical universe. The appearance of a stable physical universe then emerges from the ensemble of these observer moments. I do not think anymore that Boltzmann brain are brain or computational device, nor that the notion is well defined. But a part of Carroll reasoning could work using the Universal Dovetailing instead, which are deterministic process and do represent computations (unlike the Boltzmann brain, which, as far as I can provide sense to them are analog of the "white rabbits" or even "white noise"). In a physicalist and non computationalist context, Carroll's conclusion makes some sense. Yet, with computationalism, it looks like advocating a small non robust universe, which is move that the step 8 of the UDA shows to be not working. Bruno -- Stathis Papaioannou -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout. http://iridia.ulb.ac.be/~marchal/ -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
Re: Boltzmann Brains rule out any theory?
On 2/6/2017 9:12 AM, Stathis Papaioannou wrote:
On Mon., 6 Feb. 2017 at 11:06 pm, Ronald Held <mailto:ronaldh...@gmail.com>> wrote:
Why Boltzmann Brains Are Bad
Authors: Sean M. Carroll
Comments: 27 pages. Invited submission to a volume on Current
Controversies in Philosophy of Science, eds. Shamik Dasgupta and Brad
Weslake
Subjects: High Energy Physics - Theory (hep-th); Cosmology and
Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum
Cosmology (gr-qc); History and Philosophy of Physics (physics.hist-ph)
Some modern cosmological models predict the appearance of Boltzmann
Brains: observers who randomly fluctuate out of a thermal bath rather
than naturally evolving from a low-entropy Big Bang. A theory in which
most observers are of the Boltzmann Brain type is generally thought to
be unacceptable, although opinions differ. I argue that such theories
are indeed unacceptable: the real problem is with fluctuations into
observers who are locally identical to ordinary observers, and their
existence cannot be swept under the rug by a choice of probability
distributions over observers. The issue is not that the existence of
such observers is ruled out by data, but that the theories that
predict them are cognitively unstable: they cannot simultaneously be
true and justifiably believed.
--
Here is the link:
https://arxiv.org/pdf/1702.00850.pdf
Everything I've ever seen written about Boltzmann Brains takes the
position that they are obviously absurd. But here's another view:
Boltzmann Brains would give rise to every possible thought - every
possible observer moment. This is equivalent to the situation whereby
every possible observer moment exists necessarily as a Platonic
entity, without the need for a separate physical universe. The
appearance of a stable physical universe then emerges from the
ensemble of these observer moments.
Which means that appearance of a stable physical universe cannot be
taken as evidence for anything at all - including our thoughts about
Boltzmann brains.
Carroll argues that there are no fluctuations of the vacuum and hence no
Boltzmann brain problem:
https://www.youtube.com/watch?v=AUiMi3GHxYw
Brent
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Re: Boltzmann Brains rule out any theory?
On Mon., 6 Feb. 2017 at 11:06 pm, Ronald Held wrote: > Why Boltzmann Brains Are Bad > Authors: Sean M. Carroll > > Comments: 27 pages. Invited submission to a volume on Current > Controversies in Philosophy of Science, eds. Shamik Dasgupta and Brad > Weslake > Subjects: High Energy Physics - Theory (hep-th); Cosmology and > Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum > Cosmology (gr-qc); History and Philosophy of Physics (physics.hist-ph) > > Some modern cosmological models predict the appearance of Boltzmann > Brains: observers who randomly fluctuate out of a thermal bath rather > than naturally evolving from a low-entropy Big Bang. A theory in which > most observers are of the Boltzmann Brain type is generally thought to > be unacceptable, although opinions differ. I argue that such theories > are indeed unacceptable: the real problem is with fluctuations into > observers who are locally identical to ordinary observers, and their > existence cannot be swept under the rug by a choice of probability > distributions over observers. The issue is not that the existence of > such observers is ruled out by data, but that the theories that > predict them are cognitively unstable: they cannot simultaneously be > true and justifiably believed. > > -- Here is the link: https://arxiv.org/pdf/1702.00850.pdf Everything I've ever seen written about Boltzmann Brains takes the position that they are obviously absurd. But here's another view: Boltzmann Brains would give rise to every possible thought - every possible observer moment. This is equivalent to the situation whereby every possible observer moment exists necessarily as a Platonic entity, without the need for a separate physical universe. The appearance of a stable physical universe then emerges from the ensemble of these observer moments. -- Stathis Papaioannou -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
Boltzmann Brains rule out any theory?
Why Boltzmann Brains Are Bad Authors: Sean M. Carroll Comments: 27 pages. Invited submission to a volume on Current Controversies in Philosophy of Science, eds. Shamik Dasgupta and Brad Weslake Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); History and Philosophy of Physics (physics.hist-ph) Some modern cosmological models predict the appearance of Boltzmann Brains: observers who randomly fluctuate out of a thermal bath rather than naturally evolving from a low-entropy Big Bang. A theory in which most observers are of the Boltzmann Brain type is generally thought to be unacceptable, although opinions differ. I argue that such theories are indeed unacceptable: the real problem is with fluctuations into observers who are locally identical to ordinary observers, and their existence cannot be swept under the rug by a choice of probability distributions over observers. The issue is not that the existence of such observers is ruled out by data, but that the theories that predict them are cognitively unstable: they cannot simultaneously be true and justifiably believed. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
Re: Boltzmann Brains, consciousness and the arrow of time
Hi Bruno, > I don't understand what you mean by computations being infinitely far > away. In the UD deployment, which I will wrote UD*, all computations > begins soon or later (like all dominoes falls soon or later in the > infinite discrete dominoe-sequences). All computations reach any of > their relative computational state soon or later always after the UD > makes a finite number of steps. snip > Hmmm... The phrasing "reconstitution at infinity" does not make sense, > I think. All reconstitutions are done after a finite number of steps > of the UD. But you are right that for (the third person description) > of the first person probable experience we have to take into account > the infinite union of the computations going through the relevant > state. The reals appears here and now, because they are generated at > the limit, as a infinite union of finite computations, or finite > pieces of infinite computations. snip > OK. But it is the union which is infinite. The reconstitution can be > numbered (by a God). Yes, I see we agree - my fault. I meant the infinite union of computations - maybe "rec. at infinity" was a bit dramatic way of speaking - the way you put it is clearer. Cheers, Günther --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-l...@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 -~--~~~~--~~--~--~---
Re: Boltzmann Brains, consciousness and the arrow of time
On 09 Jan 2009, at 20:12, Günther Greindl wrote: > > Hi Bruno, > >> and Cantor get a contradiction from that. You assume the diagram is >> indeed a piece of an existing bijection in Platonia, or known by God. > > No, you misunderstand me there - I just meant that we need to take the > step to infinity - see below. > >> that you get by flipping the 0 and 1 along the diagonal of the matrix >> appearing on the right in the diagram. That sequence, thus, exists in >> Platonia, but definitely cannot belong to the list described above. > snip >> So you have to look at it, in the third person point of view as >> computations which bifurcate (or differentiate by the rule Y = II), >> and >> bifurcate again, and again, and again, OK? > > Yes, I'm with you so far. > >> And now, what you are missing. I think. It is the distinction between >> third and first person point of view. As defined in the first and >> second >> step of UDA (not the Theatetical one used in AUDA). >> >> Looking at the generation of the UD, or dovetailing on all >> computations, >> you can see the many computations being generated and you can see >> them >> differentiate or bifurcating all the "time", where here time is >> defined >> by the succession 1, 2, 3, 4, 5, ... itself. If you universal base is >> two dimensional (like with the Conway Game of Life) you can see the >> deployment as a static three dimensional conic structure. >> >> Everything there, is enumerable. At each UD step, everything is >> even finite! > snip >> But things changes when you adopt the first person point of view, >> due to >> the fact that the first person point of view cannot be aware of the >> dovetailing delays, nor of the extreme multiplication and >> redundancy of >> the computations. And if you are OK with, well, mainly here the >> step 4, >> you see that the "intuitive" measure will have to be made on the >> union >> of all computations going through the "current" state. > > Agreed. > > >> 0... >> >> I have already begin the generation of a continuum of binary >> "history": >> Indeed, all those beginning by 0. Then I write >> >> 1... >> >> So I have begin the generation of the binary sequence beginning by >> 1. As >> you see I am dovetailing (not universally though!). >> >> Then i generate all possible extensions, which give me two time >> more work. >> First the possible continuation of the one beginning by 0. >> >> 00... >> >> 01... >> > > That is how I visualized it, yes. > >> >> Now, if you interpret the 1 or 0 as results of a self-bifurcation >> in the >> UDA, then by the unawareness of delays, the first person >> indeterminacy >> of those "in front of a never stopping UD", where your computations >> are >> dovetailed, in particular on the binary infinite sequences, bears on >> set with cardinalities of continua, despite mathematically the third >> person description does not leave the enumerable. > > And here is where we seem to "disagree" - but maybe only in a trivial > sense - maybe we mean the same thing actually. > > I agree that everything is still enumerable from a third person > point of > view, and that the "continuum" arises from a 1st person point of view, > but also only if I imagine all computations of the UD - also the ones > infinitely far away. I don't understand what you mean by computations being infinitely far away. In the UD deployment, which I will wrote UD*, all computations begins soon or later (like all dominoes falls soon or later in the infinite discrete dominoe-sequences). All computations reach any of their relative computational state soon or later always after the UD makes a finite number of steps. *Some* subcomputations can be interpreted as dovetailing on the constructive ordinal, but they still reach any of their computational step in finite time. > > > I am skeptical of actual infinities in the "real=physical" world (in > my > 1-OM in only believe in potential infinities. I recall that the "physical" world is a *first person* plural observation, so with comp with have to expect "things behaving like if there was actual infinities". The "physical world" is just unreal, if we decide to say real = the ontological, in which case something is real if it belongs to the UD*, or if its existence can be proved in Robinson Arithmetic. > > > http://en.wikipedia.org/wiki/Potential_infinity > > see Bekenstein Bound, and Seth Lloyd's work on the limits of > computation), but when we say that physics is emergent from 1st person > point of view of the third person UD, we are also aware that this UD > does not exist "in" time and space (but generates it for inside > observers). Well, the UD has existed and has run in time 1991 and space Brussels :) UD* does not exist "in" time and space, given that with comp it is "time and space" which *appears* from the point of view of the observers generated by the UD. It is an open problem if we can make sense with
Re: Boltzmann Brains, consciousness and the arrow of time
Hi Bruno, > and Cantor get a contradiction from that. You assume the diagram is > indeed a piece of an existing bijection in Platonia, or known by God. No, you misunderstand me there - I just meant that we need to take the step to infinity - see below. > that you get by flipping the 0 and 1 along the diagonal of the matrix > appearing on the right in the diagram. That sequence, thus, exists in > Platonia, but definitely cannot belong to the list described above. snip > So you have to look at it, in the third person point of view as > computations which bifurcate (or differentiate by the rule Y = II), and > bifurcate again, and again, and again, OK? Yes, I'm with you so far. > And now, what you are missing. I think. It is the distinction between > third and first person point of view. As defined in the first and second > step of UDA (not the Theatetical one used in AUDA). > > Looking at the generation of the UD, or dovetailing on all computations, > you can see the many computations being generated and you can see them > differentiate or bifurcating all the "time", where here time is defined > by the succession 1, 2, 3, 4, 5, ... itself. If you universal base is > two dimensional (like with the Conway Game of Life) you can see the > deployment as a static three dimensional conic structure. > > Everything there, is enumerable. At each UD step, everything is even finite! snip > But things changes when you adopt the first person point of view, due to > the fact that the first person point of view cannot be aware of the > dovetailing delays, nor of the extreme multiplication and redundancy of > the computations. And if you are OK with, well, mainly here the step 4, > you see that the "intuitive" measure will have to be made on the union > of all computations going through the "current" state. Agreed. > 0... > > I have already begin the generation of a continuum of binary "history": > Indeed, all those beginning by 0. Then I write > > 1... > > So I have begin the generation of the binary sequence beginning by 1. As > you see I am dovetailing (not universally though!). > > Then i generate all possible extensions, which give me two time more work. > First the possible continuation of the one beginning by 0. > > 00... > > 01... > That is how I visualized it, yes. > > Now, if you interpret the 1 or 0 as results of a self-bifurcation in the > UDA, then by the unawareness of delays, the first person indeterminacy > of those "in front of a never stopping UD", where your computations are > dovetailed, in particular on the binary infinite sequences, bears on > set with cardinalities of continua, despite mathematically the third > person description does not leave the enumerable. And here is where we seem to "disagree" - but maybe only in a trivial sense - maybe we mean the same thing actually. I agree that everything is still enumerable from a third person point of view, and that the "continuum" arises from a 1st person point of view, but also only if I imagine all computations of the UD - also the ones infinitely far away. I am skeptical of actual infinities in the "real=physical" world (in my 1-OM in only believe in potential infinities. http://en.wikipedia.org/wiki/Potential_infinity see Bekenstein Bound, and Seth Lloyd's work on the limits of computation), but when we say that physics is emergent from 1st person point of view of the third person UD, we are also aware that this UD does not exist "in" time and space (but generates it for inside observers). So no problem with infinities there - I only have a problem with local physical (1-OM) infinities (as presupposed in textbook physics when using calculus for finite volumes of spacetime)- but then again, where they appear locally I think they are also indicative of the multiverse, as in Max Tegmark's suggestion that natural constants could be viewed as indexicals into the Multiverse). So, actual infinity (as opposed to potential) is always a multiverse-feature. To return to the question at hand: the full continuum, also from a first person perspective, appears only when I also take into account reconstitutions "at infinity" - because, for every finite section I consider (however large), I only have _stubs_ of full reals - and not all the reals. I think a bit along the lines like when one takes an ordinal, say "omega", and imagines that it is infinity "completed". In the same sense, we need _completed_ infinity for a real continuum (as opposed to only a subset) to arise. And, as the infinity is completed in Platonia, they contribute to the measure of 1-OMs - with the power of the full continuum. Would you agree? > only low levels (not necessarily the "bottom"). Also, I can sometimes > speculate that comp could predict there is no bottom. In what way do you think this follows from comp? Because there are histories for every arbitrarily deep probing of "physical" reality? > The real question is what wi
Re: Boltzmann Brains, consciousness and the arrow of time
Hi Günther,
On 07 Jan 2009, at 22:47, Günther Greindl wrote:
>
> thanks for your comments, I interleave my response.
>
>>> showed a glimpse of the vastness of the UD. And, I agree, _in the
>>> limit_
>>> there will be an infinite number of histories. So, as we have to
>>> also
>>> take into account infinite delay, we must take this limit into
>>> account
>>> and have infinite histories going through a "state" (do I
>>> understand you
>>> correctly?).
>>
>> I guess you were meaning that we have to take into account an
>> infinity
>> of arbitrary long (but finite) delays. OK.
>
> Hmm, if we have an infinity of arbitrary long but finite delays,
> then I
> can only see aleph_0 histories (because we never take the "step to
> infinity" - we can enumerate all histories.
>
> Only if we take the "step to infinity" (as in Cantor diagonalization,
> were we presuppose the complete listing of the reals and the diagonal
> does not fit "at infinity") would we get 2^aleph_0 histories - or am I
> missing something here?
Cantor's proof is a "reductio ad absurdo". It assumes there is a one
one correspondence, or bijection, between the positive integers and
the infinite sequence on {0, 1} say. Such correspondence could be
partially described by the diagram
1 1001000 ...
2 01101001100 ...
3 11000100111 ...
4 1110000 ...
5 10100110101 ...
6 00010111011 ...
7
...
and Cantor get a contradiction from that. You assume the diagram is
indeed a piece of an existing bijection in Platonia, or known by God.
But if such a bijection exist, or if God can conceive that
correspondence, then there is a special sequence that God can conceive
too, and that indeed you can "bulld" from that diagram, indeed the
sequence
001110...
that you get by flipping the 0 and 1 along the diagonal of the matrix
appearing on the right in the diagram. That sequence, thus, exists in
Platonia, but definitely cannot belong to the list described above. If
it was in the list, there would be a number k
k --- 001110...
But by definition of the sequence, the kth decimal of that number k
will be the flip of itself, meaning that 0 = 1. OK?
The reasoning did not depend on the choice of any one one
correspondence, so that we know that for each correspondence there is
a corresponding anti-diagonal sequence, refuting the assertion that
correspondence could exhaust the set of all infinite binary sequences.
The set of binary sequence is thus not listable, not enumerable, not
countable.
You can visualise geometrically the contradictions for any candidate
correspondence by the intersection of the line defined by the
corresponding number k and the diagonal of the matrix describing the
correspondence. Note that the diagonal makes to contradiction
appearing always in a finite time.
I insist on this diagonal because it is the main tool of the AUDA. A
very similar diagonal shows the existence of enumerable but non
recursively enumerable set of numbers, which have some role in
"machine's theology" (or more quotes).
But then, recall the UD dovetails on the infinite computation, and
sometimes dovetails those infinite computation with the generation of
the binary sequences.
So you have to look at it, in the third person point of view as
computations which bifurcate (or differentiate by the rule Y = II),
and bifurcate again, and again, and again, OK?
And now, what you are missing. I think. It is the distinction between
third and first person point of view. As defined in the first and
second step of UDA (not the Theatetical one used in AUDA).
Looking at the generation of the UD, or dovetailing on all
computations, you can see the many computations being generated and
you can see them differentiate or bifurcating all the "time", where
here time is defined by the succession 1, 2, 3, 4, 5, ... itself. If
you universal base is two dimensional (like with the Conway Game of
Life) you can see the deployment as a static three dimensional conic
structure.
Everything there, is enumerable. At each UD step, everything is even
finite!
But things changes when you adopt the first person point of view, due
to the fact that the first person point of view cannot be aware of the
dovetailing delays, nor of the extreme multiplication and redundancy
of the computations. And if you are OK with, well, mainly here the
step 4, you see that the "intuitive" measure will have to be made on
the union of all computations going through the "current" state.
There is a continuum of such infinite computations, if only due to
that entangling of computation on the dovetailing on the reals and the
Y = II rule.
The third person probabilities for the *first* person point of views
have to bear on the fact that although the reals or the binary
sequence are not enumerable it is easy to write a simple program which
generates them all. This is not always well und
Re: Boltzmann Brains, consciousness and the arrow of time
- Original Message - From: "Günther Greindl" To: Sent: Wednesday, January 07, 2009 4:47 PM Subject: Re: Boltzmann Brains, consciousness and the arrow of time > We need only turing emulability, because quantum states, > although not copyable, are "preparable" (in the quantum "prepare" sense) What is the quantum "prepare" sense? Could someone please clarify the foregoing quote? m.a. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-l...@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 -~--~~~~--~~--~--~---
Re: Boltzmann Brains, consciousness and the arrow of time
Hi Bruno, thanks for your comments, I interleave my response. >> showed a glimpse of the vastness of the UD. And, I agree, _in the limit_ >> there will be an infinite number of histories. So, as we have to also >> take into account infinite delay, we must take this limit into account >> and have infinite histories going through a "state" (do I understand you >> correctly?). > > I guess you were meaning that we have to take into account an infinity > of arbitrary long (but finite) delays. OK. Hmm, if we have an infinity of arbitrary long but finite delays, then I can only see aleph_0 histories (because we never take the "step to infinity" - we can enumerate all histories. Only if we take the "step to infinity" (as in Cantor diagonalization, were we presuppose the complete listing of the reals and the diagonal does not fit "at infinity") would we get 2^aleph_0 histories - or am I missing something here? > I will let you elaborate on this. But note that if my consciousness > "here and now" supervenes on "past activity", I will elaborate, but please give me time till February, before I will not be able to work on this. >then the comp substitution > level has to be very "low" indeed. Yes, very low, that was the idea. > You will also need a notion of "block > universe". The comp doctor will have to be able to manipulate > "time-lines". No, it is only that he will have to respect "relative embeddings" - scanning and reconsitution will only be correct regarding _this_ universe and very similar universes, but not with regard to arbitrary computations in Platonia. >Remember that even deep, in the sense of Bennett(*) , > computer state, can be copied efficiently, so that when you say that > (*) Bennett, C. H. (1988). Logical Depth and Physical Complexity. In > Herken, R., editor, /The Universal Turing Machine A Half-Century > Survey/, pages 227-258. Oxford University Press. > Thanks for the reference, I will consider this... >> If we assume the whole universe to be an automaton, also it's >> inhabitants would be "mechanical" =effectively computable of course - >> but maybe they could then not be duplicated, because, when person A were >> trying to make a scan of the properties of person B, the universe as a >> whole would move into different states and make complementary >> observables - which _could_ be necessary for a duplication - unavailable. > > > OK. But your level has to be really at the bottom, not only below the > quantum level. I recall you that the no-cloning theorem does not prevent > us to be quantum computer. Right: we cannot say yes to any doctor, yet > UDA goes through because at the seventh step the "copy need" is > eliminated. We need only turing emulability, because quantum states, > although not copyable, are "preparable" (in the quantum "prepare" sense) > in many exemplaries, and indeed the UD does doevetail on all quantum > computations. Agreed. > I think that your bottom really means: my brain is the whole of reality. In the sense that the brain state depends on the whole of reality, and if my brain state (or anyone elses) changes then the whole universe transitions into a new state, yes, but not in the solipsitic form. >> This may only work if consciousness supervenes not on "isolated" >> computations, but only if it is embedded in computations constructing >> whole universes - but then again, we can't exclude this a priori. >> >> And we would still have to consider many worlds, but these would then >> indeed be _worlds_ and not only OMs with incoming/outgoing histories (of >> course it would still seem this way from the concrete OM, but with >> greatly reduced danger of white rabbits) - the laws of physics would not >> emerge for OM's stranded in the UD deployment but for OM's embedded >> already in highly structured computational environments - we would only >> have to take into account duplications of OM's where also whole >> universes are duplicated. > > > Hmmm (I guess I use "OM" in a larger sense: those worlds remain > computable (assuming comp and "bottom-level") and, as such, are > generated by the UD). I guess I should not! Could you please clarify what exactly you mean with OM? Maybe this can clear up some misunderstandings? > Well, if the quantum laws are derived from comp, then the "platonic > histories" are manipulable in a sense similar to the use of parallel > universe (or superposition states) in a quantum computer. Also, the comp > Platonia need not be greater that Sigma_1 Arithmetical truth (which is > a tiny part of arithmetical truth, itself a tiny part of mathematical > truth): the deployment is really just the constructives consequences of > 0, succession, addition and multiplication. And it is big as seen and > infered from inside, cf Hubble and ... the quantum multiverse. The > inaccessibility for manipulation is more of the type: no one can make 17 > even, not even a God. Agreed. Best Wishes, Günther -
Re: Boltzmann Brains, consciousness and the arrow of time
Hi Günther, I agree with your main point. My comments below concerns only details. On 03 Jan 2009, at 23:53, Günther Greindl wrote: > > Hi Bruno, > > first of all thanks for the long answer, and yes, it was very helpful. > > You described the production of all reals with a very vivid imagery; > it > showed a glimpse of the vastness of the UD. And, I agree, _in the > limit_ > there will be an infinite number of histories. So, as we have to also > take into account infinite delay, we must take this limit into account > and have infinite histories going through a "state" (do I understand > you > correctly?). I guess you were meaning that we have to take into account an infinity of arbitrary long (but finite) delays. OK. > > > As to the interacting programs: do you consider them purely because > they > are part of UD or do you think this is a possible way to share > histories? Both. > > > (I am interested in this because I find COMP very convincing, though I > am still a bit worried about solipsism). Me too. Without Everett's "confirmation" I would perhaps have suspected absence of first person plurality, and I would have believed that comp leads to solipsism (and in that case I would have preferred to be a plumber or something ...). > > > I am also preparing a few thoughts (in a later post, but see hints > below) on how consciousness might supervene on large parts of past > causal histories, thereby also steering a bit away from solipsism > (arguing via the concept of external realism from analytic philosophy, > summarized by Putnam's "meaning is not in the head"). I will let you elaborate on this. But note that if my consciousness "here and now" supervenes on "past activity", then the comp substitution level has to be very "low" indeed. You will also need a notion of "block universe". The comp doctor will have to be able to manipulate "time-lines". Remember that even deep, in the sense of Bennett(*) , computer state, can be copied efficiently, so that when you say that consciousness here and now could supervene on the past, you will have to use not only a low level, but also a rather sophisticated notion of "block universe". I am not sure making the level just low will be enough. But from the logical point of view, this could be conceivable. You should develop perhaps. (*) Bennett, C. H. (1988). Logical Depth and Physical Complexity. In Herken, R., editor, The Universal Turing Machine A Half-Century Survey, pages 227-258. Oxford University Press. > I also have another question (related to the above issue of > solipsism): > > We have considered COMP and MAT and seen that the two are not really > compatible. > > But you also say that with COMP, the universe itself is not computable > (I understand why, and I agree with your reasoning as you have > presented > it). > > But I have one "worry": what if the subsitution level is "at the > bottom" > of the universe - (for a moment drawing on materialist intuitions, > the > universe in the "normal" sense and not considering infinite histories > for the moment). > > If the universe is a computation, then also an individual in the > universe is part of this computation. But this individual can't be > "duplicated" because of the quantum no-cloning theorem (that is what I > mean with "at the bottom" - not above the quantum level). > > Svozil for instance refers in a number of papers to the work of Moore > and Finkelstein that show, assuming we have an automaton, we would > witness complementarity. > > http://tph.tuwien.ac.at/~svozil/publ/publ.html > > (see for instance these overview papers: > > Svozil, K. ``How real are virtual realities, how virtual is reality? > The > constructive re-interpretation of physical undecidability'', > Complexity, > 1, 43-54 (1996). > > Svozil, K. Computational Universes Chaos, Solitons & Fractals, 2005, > 25, > 845-859 > > Svozil, K. Physical Unknowables physics/0701163, 2007) I have read all Svozil's book (but none of its papers). I appreciate and there are complementarities with the UDA reasoning, although it needs some work to make this precise. By the way the quantum logic automaton is another example to get a quantum logic in a classical frame without contradicting the "no-go" theorems that Stephen was alluding toward. > The results of course would also apply if we were "solipsist" > automatons > and "the whole" not (so the arguments are quite compatible with > varying > versions of machine conception (universe/person) ). > > I am just saying that we can't know if we are "separable" from the > universe. > > To state it differently (and to make the connection with > complementarity > and duplication): > > If we assume the whole universe to be an automaton, also it's > inhabitants would be "mechanical" =effectively computable of course - > but maybe they could then not be duplicated, because, when person A > were > trying to make a sc
Re: Boltzmann Brains, consciousness and the arrow of time
Hi Stephen, Stephen Paul King wrote: > Nice post! Coments soon. Thanks :-) Looking forward to the comments. > Speaking of Svozil's work, please see: Cristian S. Calude, Peter H. > Hertling and Karl Svozil, ``Embedding Quantum Universes in Classical Ones'', > Foundations of Physics 29(3), 349-390 (1999) [abstract], [CrossRef > DOI:10.1023/A:1018862730956], [pdf], [pdf], [tex], [ps]. Thanks for the tip, will have a look at it! Best Wishes, Günther --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-l...@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 -~--~~~~--~~--~--~---
Re: Boltzmann Brains, consciousness and the arrow of time
On 04 Jan 2009, at 03:09, Stephen Paul King wrote: > > Hi Günther, > >Nice post! Coments soon. > >Speaking of Svozil's work, please see: Cristian S. Calude, Peter H. > Hertling and Karl Svozil, ``Embedding Quantum Universes in Classical > Ones'', > Foundations of Physics 29(3), 349-390 (1999) [abstract], [CrossRef > DOI:10.1023/A:1018862730956], [pdf], [pdf], [tex], [ps]. Nice work. It is in the line of the beautiful theorem of Kochen and Specker. > > >How can we derive quantum logics from purely integer (or even real > number) based logics? This paper seems to yeild a no-go theorem! And this confirms the MEC prediction (or re-prediction) that the logic of the physical reality cannot be boolean. I recall you that the material hypostases, when interpreted in arithmetic, gives quantum like logics. There is no reason to suppose they can be embedded in Boolean logics. The no-go theorems shows that quantum logic cannot be embedded in classical logic in observable value preserving way. Such no go-theorems cannot be applied to the AUDA arithmetical quantization, which concerns the way self-observing machine have to structure the comp physical reality. Remember the result by Goldblatt(*) 1974: there is a boolean way to interpret "epistemically" quantum logic (by the modal logic B). The arithmetical quantization, which captures the first person (plural) points of view, gives a modal logic B (without necessitation rule). It would be a nice research project to show that this extends the no-go theorems to the comp physical quantum logics. This would confirm the highly non boolean (and non Aristotelian) nature of matter, or appearance of matter. The mechanist quantum logic is not derived from numbers, but from numbers personal points ov view: what numbers can observe and share when they observe themselves, and this with a very general notion of observation. It is like the MWI, the most weird is the quantum world, the more we can believe that comp is correct, given that comp entails a rather highly non classical view of the physical reality. All right? More generally and perhaps more simply the no-go theorems forbid a classical reality, it does not forbid a classical *theory* about a non classical reality. The (meta)logic of quantum mechanics itself is classical. If you believed that the non go theorems is a problem for comp, it means that you could be confusing levels with metalevels. All right? Best, Bruno PS Kim, Günther, I will comment your posts with some details asap, but I have some new year activities ... (*) Goldblatt, R. I. (1974). Semantic Analysis of Orthologic. Journal of Philosophical Logic, 3:19-35. Also in Goldblatt, R. I. (1993). Mathematics of Modality. CSLI Lectures Notes, Stanford California, page 81-97. > > - Original Message - > From: "Günther Greindl" > To: > Sent: Saturday, January 03, 2009 5:53 PM > Subject: Re: Boltzmann Brains, consciousness and the arrow of time > > > > Hi Bruno, > > first of all thanks for the long answer, and yes, it was very helpful. > > You described the production of all reals with a very vivid imagery; > it > showed a glimpse of the vastness of the UD. And, I agree, _in the > limit_ > there will be an infinite number of histories. So, as we have to also > take into account infinite delay, we must take this limit into account > and have infinite histories going through a "state" (do I understand > you > correctly?). > > As to the interacting programs: do you consider them purely because > they > are part of UD or do you think this is a possible way to share > histories? > > (I am interested in this because I find COMP very convincing, though I > am still a bit worried about solipsism). > > I am also preparing a few thoughts (in a later post, but see hints > below) on how consciousness might supervene on large parts of past > causal histories, thereby also steering a bit away from solipsism > (arguing via the concept of external realism from analytic philosophy, > summarized by Putnam's "meaning is not in the head"). > > I also have another question (related to the above issue of > solipsism): > > We have considered COMP and MAT and seen that the two are not really > compatible. > > But you also say that with COMP, the universe itself is not computable > (I understand why, and I agree with your reasoning as you have > presented > it). > > But I have one "worry": what if the subsitution level is "at the > bottom" > of the universe - (for a moment drawing on materialist intuitions, > the > universe in the "normal" sense and not considering infinite histories > for the
Re: Boltzmann Brains, consciousness and the arrow of time
Hi Günther, Nice post! Coments soon. Speaking of Svozil's work, please see: Cristian S. Calude, Peter H. Hertling and Karl Svozil, ``Embedding Quantum Universes in Classical Ones'', Foundations of Physics 29(3), 349-390 (1999) [abstract], [CrossRef DOI:10.1023/A:1018862730956], [pdf], [pdf], [tex], [ps]. How can we derive quantum logics from purely integer (or even real number) based logics? This paper seems to yeild a no-go theorem! Onward! Stephen - Original Message - From: "Günther Greindl" To: Sent: Saturday, January 03, 2009 5:53 PM Subject: Re: Boltzmann Brains, consciousness and the arrow of time Hi Bruno, first of all thanks for the long answer, and yes, it was very helpful. You described the production of all reals with a very vivid imagery; it showed a glimpse of the vastness of the UD. And, I agree, _in the limit_ there will be an infinite number of histories. So, as we have to also take into account infinite delay, we must take this limit into account and have infinite histories going through a "state" (do I understand you correctly?). As to the interacting programs: do you consider them purely because they are part of UD or do you think this is a possible way to share histories? (I am interested in this because I find COMP very convincing, though I am still a bit worried about solipsism). I am also preparing a few thoughts (in a later post, but see hints below) on how consciousness might supervene on large parts of past causal histories, thereby also steering a bit away from solipsism (arguing via the concept of external realism from analytic philosophy, summarized by Putnam's "meaning is not in the head"). I also have another question (related to the above issue of solipsism): We have considered COMP and MAT and seen that the two are not really compatible. But you also say that with COMP, the universe itself is not computable (I understand why, and I agree with your reasoning as you have presented it). But I have one "worry": what if the subsitution level is "at the bottom" of the universe - (for a moment drawing on materialist intuitions, the universe in the "normal" sense and not considering infinite histories for the moment). If the universe is a computation, then also an individual in the universe is part of this computation. But this individual can't be "duplicated" because of the quantum no-cloning theorem (that is what I mean with "at the bottom" - not above the quantum level). Svozil for instance refers in a number of papers to the work of Moore and Finkelstein that show, assuming we have an automaton, we would witness complementarity. http://tph.tuwien.ac.at/~svozil/publ/publ.html (see for instance these overview papers: Svozil, K. ``How real are virtual realities, how virtual is reality? The constructive re-interpretation of physical undecidability'', Complexity, 1, 43-54 (1996). Svozil, K. Computational Universes Chaos, Solitons & Fractals, 2005, 25, 845-859 Svozil, K. Physical Unknowables physics/0701163, 2007) The results of course would also apply if we were "solipsist" automatons and "the whole" not (so the arguments are quite compatible with varying versions of machine conception (universe/person) ). I am just saying that we can't know if we are "separable" from the universe. To state it differently (and to make the connection with complementarity and duplication): If we assume the whole universe to be an automaton, also it's inhabitants would be "mechanical" =effectively computable of course - but maybe they could then not be duplicated, because, when person A were trying to make a scan of the properties of person B, the universe as a whole would move into different states and make complementary observables - which _could_ be necessary for a duplication - unavailable. This may only work if consciousness supervenes not on "isolated" computations, but only if it is embedded in computations constructing whole universes - but then again, we can't exclude this a priori. And we would still have to consider many worlds, but these would then indeed be _worlds_ and not only OMs with incoming/outgoing histories (of course it would still seem this way from the concrete OM, but with greatly reduced danger of white rabbits) - the laws of physics would not emerge for OM's stranded in the UD deployment but for OM's embedded already in highly structured computational environments - we would only have to take into account duplications of OM's where also whole universes are duplicated. So, what I am getting at, wouldn't you have to modify your argument - the reversal physics/machine psychology - insofar that not only a substitution level exists (COMP), but that this level is "separable" from a possible universe-machi
Re: Boltzmann Brains, consciousness and the arrow of time
Hi Bruno, first of all thanks for the long answer, and yes, it was very helpful. You described the production of all reals with a very vivid imagery; it showed a glimpse of the vastness of the UD. And, I agree, _in the limit_ there will be an infinite number of histories. So, as we have to also take into account infinite delay, we must take this limit into account and have infinite histories going through a "state" (do I understand you correctly?). As to the interacting programs: do you consider them purely because they are part of UD or do you think this is a possible way to share histories? (I am interested in this because I find COMP very convincing, though I am still a bit worried about solipsism). I am also preparing a few thoughts (in a later post, but see hints below) on how consciousness might supervene on large parts of past causal histories, thereby also steering a bit away from solipsism (arguing via the concept of external realism from analytic philosophy, summarized by Putnam's "meaning is not in the head"). I also have another question (related to the above issue of solipsism): We have considered COMP and MAT and seen that the two are not really compatible. But you also say that with COMP, the universe itself is not computable (I understand why, and I agree with your reasoning as you have presented it). But I have one "worry": what if the subsitution level is "at the bottom" of the universe - (for a moment drawing on materialist intuitions, the universe in the "normal" sense and not considering infinite histories for the moment). If the universe is a computation, then also an individual in the universe is part of this computation. But this individual can't be "duplicated" because of the quantum no-cloning theorem (that is what I mean with "at the bottom" - not above the quantum level). Svozil for instance refers in a number of papers to the work of Moore and Finkelstein that show, assuming we have an automaton, we would witness complementarity. http://tph.tuwien.ac.at/~svozil/publ/publ.html (see for instance these overview papers: Svozil, K. ``How real are virtual realities, how virtual is reality? The constructive re-interpretation of physical undecidability'', Complexity, 1, 43-54 (1996). Svozil, K. Computational Universes Chaos, Solitons & Fractals, 2005, 25, 845-859 Svozil, K. Physical Unknowables physics/0701163, 2007) The results of course would also apply if we were "solipsist" automatons and "the whole" not (so the arguments are quite compatible with varying versions of machine conception (universe/person) ). I am just saying that we can't know if we are "separable" from the universe. To state it differently (and to make the connection with complementarity and duplication): If we assume the whole universe to be an automaton, also it's inhabitants would be "mechanical" =effectively computable of course - but maybe they could then not be duplicated, because, when person A were trying to make a scan of the properties of person B, the universe as a whole would move into different states and make complementary observables - which _could_ be necessary for a duplication - unavailable. This may only work if consciousness supervenes not on "isolated" computations, but only if it is embedded in computations constructing whole universes - but then again, we can't exclude this a priori. And we would still have to consider many worlds, but these would then indeed be _worlds_ and not only OMs with incoming/outgoing histories (of course it would still seem this way from the concrete OM, but with greatly reduced danger of white rabbits) - the laws of physics would not emerge for OM's stranded in the UD deployment but for OM's embedded already in highly structured computational environments - we would only have to take into account duplications of OM's where also whole universes are duplicated. So, what I am getting at, wouldn't you have to modify your argument - the reversal physics/machine psychology - insofar that not only a substitution level exists (COMP), but that this level is "separable" from a possible universe-machine (the possibility of which we can't exclude at the beginning of the argument). A kind of qualified COMP, QCOMP? Of course, the variant where the whole universe is necessary for duplication would still be machine psychology, but at a different level - at the universe level (classical sense again) and not at the level of everday conception of persons. Maybe COMP with the assumption that consciousness needs whole universes to supervene on (I don't mean that a universe is conscious; persons, brains would be conscious, but they would need the surrounding computations supplied by the universe to provide "meaning") is even preferable to the view that one can duplicate a person from _within_ a universe (because of the white rabbit problem). Reading through my post above again, I believe that your COMP ar
Re: Boltzmann Brains, consciousness and the arrow of time
Hi Günther, On 01 Jan 2009, at 23:58, Günther Greindl wrote: > > Bruno, > > I have also wanted to ask how you come to 2^aleph_zero > >> Well, in part this results from the unbounded dumbness of the >> universal doevtailing procedure which dovetails on all programs but > >> also on all non interacting collection of programs (as all >> interacting >> one). > > How do you discern interacting/non-interacting programs? What do you > mean exactly with the term in regard to UD? To write and implement a Universal Dovetailer, you have to fix a universal programming language (or machine). Then the UD will generate the list of programs P_1, P_2, P_3, ... and run them by little pieces, let us say of one running step, and this for each program in such a way that it dovetails on all the executions, including those who does not stop, which we cannot avoid. Let us assume tthat the sequence P_1, P_2, P_3, ... P_i ... is the sequence of the zero variable programs (this changes nothing). Now a computation, for example, the computation of P_0, will itself be a sequence of computational steps, like P_1^1, P_1^2, P_1^3, etc ... To run the UD, we dovetail or zig zag on the programs and their computational steps. Exercise: add some relevant zig zagging to the following infinite diagram: P_1^1, P_1^2, P_1^3, P_1^4, ... P_2^1, P_2^2, P_2^3, P_2^4, ... P_3^1, P_3^2, P_3^3, P_3^4, ... P_4^1, P_4^2, P_4^3, P_4^4, ... ... A solution: P_1^1, P_1^2, P_2^1, P_3^1, P_2^2, P_1^3, P_1^4, P_2^3, P_3^2, P_4^1, ... Each computational step P_i^j, of the ith program up to the jth step is completely independent of any other computations P_k^h, when i is different from k. Such computations do not interact. The DU, if programmed correctly, will never let them share the memories or interact in any way. But for each couple (P_i, P_k) there is another program, P_h in the (infinite but enumerable) list P_i which is a mini-dovetailer of the pair of programs (P_i, P_k). This means P_h dovetails itself on the execution of the two programs P_i and P_k. Indeed, trivially, the universal dovetailer execute all the possible dovetailing, the universal one and all the other one. Again, the two new computations of P_i and P_k does not interact. But that is not enough, for all couple of programs (P_i, P_k) there is third program P_g, which you can seen as a bad or buggy dovetailer on the pair (P_i, P_k), which will execute P_i and P_k again, but with just one shared memory, so that progress in the running of one of them will destroy the memory of the other. In that sense the buggy mini- dovetailer makes P_i and P_k interact, in one way. Given that any digital interaction process, it can be simulated by a program, and the UD will soon or later simulate that interaction. For another example, the UD will run all patterns of the game of life, but also all couple of such patterns, all triples, all quadruples, actually all finite pieces of possible "Eden garden" of possible cellular automata. You can actually imagine any ways of making two programs or machines interact, soon or later the UD will generate ONE computation which will run the interaction of those machines, yet such computation will not interact with the proper other UD-computations. The UD will even generate a universal buggy dovetailing computation which makes all programs interact with each other, in all possible ways. All right? Please ask if something is not clear. It is simpler to explain all this with conical drawings, and the internal zig zagging. > > >> In particular each computation is "entangled" to dovetailing on >> the reals, > > What do you mean by this? How do the reals enter the picture? Do you remember the iterated self-duplication experiment? Suppose I invite you to make that experience. But your boss asked you to do some computation P (and thus your computation looks like P^1, P^2, etc... (the number = the steps of your computation). So, you will do your computation and simultaneously do the iterated self-duplication. To simplify I will assume that you do one step of your computation at each duplication. I duplicate you iteratively in two rooms, one with the number zero written on the wall, the other with the number one on the wall. OK? And during that time you make the computation (to please your boss). So you compute P, get the first step of the computation: P^1, go to my duplicator (where you are scanned---and this includes your "step result" P^1annihilated, and reconstituted in the zero-room and in the one-room. The two of you come back, each one of you compute one step of the computation to get P^2, and enter the duplicator again. Both are scanned, including the P^2 step-result, and then annihilated and reconstituted again in the two rooms. The four of you come back, compute the third step of the computation, and enter again the annihilator , the ei
Re: Boltzmann Brains, consciousness and the arrow of time
On 31 Dec 2008, at 23:53, Brent Meeker wrote: > > The present moment in quantum cosmology: challenges to the arguments > for the elimination of time > Authors: Lee Smolin > (Submitted on 29 Apr 2001) > Abstract: Barbour, Hawking, Misner and others have argued that time > cannot play an essential role in the formulation of a quantum theory > of cosmology. Here we present three challenges to their arguments, > taken from works and remarks by Kauffman, Markopoulou and Newman. > These can be seen to be based on two principles: that every > observable in a theory of cosmology should be measurable by some > observer inside the universe, and all mathematical constructions > necessary to the formulation of the theory should be realizable in a > finite time by a computer that fits inside the universe. We also > briefly discuss how a cosmological theory could be formulated so it > is in agreement with these principles. > Comments: This is a slightly revised version of an essay published > in Time and the Instant, Robin Durie (ed.) Manchester: Clinamen > Press, 2000 > Subjects: General Relativity and Quantum Cosmology (gr-qc) > Cite as: arXiv:gr-qc/0104097v1 And On 02 Jan 2009, at 04:01, Kim Jones wrote: Edge Question 2009: "What Will Change Everything?" http://www.edge.org/q2009/q09_9.html#smolin By some token which would be premature to explain, Smolin's 2001 papers is very near the "correct" physics that we can extract from the talk of the self-observing universal machine, especially from the 3th and 5th arithmetical hypostases. This includes an impossibility of eliminating time, a non standard notion of truth, etc. But such physics is really a first person construct of the lobian machine, and to explain this you have to agree that elementary arithmetical truth is just out of time, out of space, actually out of physics, and indeed it is math. So to be frank, I disagree strongly with many points of his Edge Question 2009, even if I can agree with the type of physics he is working about. But more generally, any physics, theoretical or experimental, which would contradict the physics extracted from the comp hyp, would be an empirical refutation of the comp hyp. Now Everett physics confirms most of the easiest physical things you can derive from MEC, and, well Smolin's physics too. The apparent contradiction between Smolin and Everett-Deutsch are more due to the attachment to physicalism and Aristotelism than facts or even theory. I am afraid that Smolin's 2009 reifies good ideas in Smolin's 2001, sending him to inconsistency or (cosmo)solipsism. I need some amount of "timeless truth" to even take my doubt on many other so-called "timeless truth" seriously enough. Descartes saw this. If you want make me believe that the primality of 17 is time and space dependent, I will ask you to give me the function describing this dependence, or give me an argument explaining why such a function has to exist. And take care that your argument is not time and space dependent itself. I don't understand either (in the Edge 2009) is argument for ethics, just after his argument for relativism. You can search Smolin in the everything archive, for what I have already said about his work here, and we can come back on this, perhaps when everyone grasp the UDA proof, and a bit of the AUDA. I just see Lennart Nilsson post: yes I think so too, although I guess Smolin could perhaps give a more apt and nuanced answer, but reintroducing an absolute moment contradict Einstein relativity (but perhaps not Poincaré's very close relativity theory, sometimes confused with Einstein one). 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-l...@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 -~--~~~~--~~--~--~---
Re: Boltzmann Brains, consciousness and the arrow of time
Bruno, I have also wanted to ask how you come to 2^aleph_zero > Well, in part this results from the unbounded dumbness of the > universal doevtailing procedure which dovetails on all programs but > also on all non interacting collection of programs (as all interacting > one). How do you discern interacting/non-interacting programs? What do you mean exactly with the term in regard to UD? > In particular each computation is "entangled" to dovetailing on > the reals, What do you mean by this? How do the reals enter the picture? Cheers, Günther --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-l...@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 -~--~~~~--~~--~--~---
Re: Boltzmann Brains, consciousness and the arrow of time
Hal, I have entertained quite similar musings some time ago, and this led me to a position I called "naive materialism" NMAT some time ago on this list - that causality does not matter, and consciousness would supervene on the material states directly - and both backward and forward versions would actually be "the same" from an endophysical perspective. But the problem of these considerations is that indeed we get the BB issue and causality loses it's role, leaving us with a quite strange tangle of states. Considering that in a fundamental theory, time shouldn't be a parameter chugging along, and we are still considering an "external time" (where the cosmic perturbations are actually happening) as opposed to the endophysical time registered by the brains in the fluctuations, the thinking along these lines reveals itself to be even more disappointing. In the meantime I have come to agree with Bruno: "It seems to me that your reasoning illustrates well the problems with physical supervenience and physicalism, and perhaps ASSA." The solution Bruno has worked out is much more satisfying - supervenience on computations, and the "physical" emerging from the most probable histories. It is a form of objective idealism, avoiding the problems of subjective idealisms which are inimical to scientific inquiry. In sum, BBs and perturbing universes are, I think, more evidence that there is something wrong with materialism (and I say this having arrived on this list being a materialist ;-). Cheers, Günther Hal Finney wrote: > Sometimes we consider here the nature of consciousness, whether observer > moments need to be linked to one another, the role of causality in > consciousness, etc. I thought of an interesting puzzle about Boltzmann > Brains which offers a new twist to these questions. > > As most readers are aware, Boltzmann Brains relate to an idea of Boltzmann > on how to explain the arrow of time. The laws of physics seem to be time > symmetric, yet the universe is grossly asymmetric in time. Boltzmann > proposed that if you had a universe in a maximum entropy state, say a > uniform gas, then given enough time, the gas would undergo fluctuations > to regions of lower entropy. Sometimes, purely at random, clumps of > molecules would happen to form. Even more rarely, these clumps might be > large and ordered. Given infinite time, one could even have an entire > visible-universe worth of matter clump together in an ordered fashion, > from which state it would then decay into higher entropy conditions. Life > could evolve during this decay, observe the universe around it, and find > itself in conditions much like our own. > > The Boltzmann Brain is a counter-argument, suggesting that the universe > and everything else is redundant; all you need is a brain to form via > a spontaneous random fluctuation, and to hold together long enough to > engage in a few moments of conscious thought. Such a Boltzmann Brain is > far more likely to form than an entire universe, hence the vast majority > of conscious thoughts in such a model will be in Boltzmann Brains and not > in brains in large universes. If we were tempted to explain the arrow of > time in this way, we must accept that the universe is an illusion and > that we are actually Boltzmann Brains, a conclusion which most people > don't like. > > Now this scenario can be criticized in many ways, but I want to emphasize > a couple of points which aren't always appreciated. The first is that the > Boltzmann scenario, whether a whole universe or just a Brain is forming, > is basically time symmetric. That means that if you saw a movie of a > Boltzmann universe forming and then decaying back to random entropy, > you would not be able to tell which way the movie was running, if it > were to be reversed. (This is an unavoidable consequence of the time > symmetry of the underlying physics.) It follows that while the universe > is moving into the low-entropy state, it must be evolving backwards. That > is, an observer from outside would see time appearing to run backwards. > Eggs would un-scramble themselves, objects would fall upwards from the > ground, ripples would converge on spots in lakes from which rocks would > then leap from the water, and so on. > > At some point this time reversal effect would stop, and the universe > would then proceed to evolve back into a high entropy state, now with time > going "forwards". Now, the forward phase will not in general be an exact > mirror image of the reverse, because of slight random fluctuations and > the like, but it will be an alternate path that essentially starts with > the same initial conditions. So we will see one path backwards into the > minimum-entropy state, a
Re: Boltzmann Brains, consciousness and the arrow of time
On 01 Jan 2009, at 21:10, Brent Meeker wrote: > > Bruno Marchal wrote: >> >> It seems to me that your reasoning illustrates well the problems with >> physical supervenience and physicalism, and perhaps ASSA. >> >> In any case the Universal Dovetailer generates all such gaz universes >> generating the Boltzmann brains. Now the probability that you are >> implemented by a particular Boltzmann brain is null, as it is null >> for >> any particular. With the comp supervenience you have to "attach" >> consciousness on ALL the histories going through your computational >> state. It is a sort of double cone of histories. > > Are you assuming time as fundamental here? If time is merely > inferred then it > seems that states of Bbs could fit into the inferred time sequence > as well as > states that arose in some other way. I assume only the sequence 0, 1, 2, 3, 4, 5, ... or the axioms of Robinson arithmetic, or Peano. This is enough to recognize the working of a universal dovetailer, and the execution of all programs. It is not infered but postulate. You can call it a digital time, or you can unravel such a dynamical deploiment into a statical n n+1 dimensional cone (with n the dimension of the space used by your starting universal machine (but some have no concept of dimension, and the statical picture is more a logical than a geometrical one). It is not "physical time", nor even the subjective time builded by internal entities. > > >> >> We cannot belong to the aleph_zero Boltzmann brains state, because, >> from our first person (plural) point of views we already belongs to >> the 2^aleph_zero "winning" (infinite) histories. (or comp is wrong). > > I don't understand the counting measure. Why are histories order > 2^apleph_0? Well, in part this results from the unbounded dumbness of the universal doevtailing procedure which dovetails on all programs but also on all non interacting collection of programs (as all interacting one). In particular each computation is "entangled" to dovetailing on the reals, and infinite computations are multiplied into 2^aleph_zero by this entanglement with the reals. Now this is a good thing because it means that the stable histories will be those who manage that background noise, who exploits it probably. Our mind states are enumerable, but our histories are not. Bruno > > > Brent > > >> >> This is a case for RSSA indeed. I think. Bb are reduced to the >> "usual" >> white rabbits histories, with RSSA, it seems to me. >> >> Bruno >> >> >> >> On 31 Dec 2008, at 22:58, Hal Finney wrote: >> >>> Sometimes we consider here the nature of consciousness, whether >>> observer >>> moments need to be linked to one another, the role of causality in >>> consciousness, etc. I thought of an interesting puzzle about >>> Boltzmann >>> Brains which offers a new twist to these questions. >>> >>> As most readers are aware, Boltzmann Brains relate to an idea of >>> Boltzmann >>> on how to explain the arrow of time. The laws of physics seem to be >>> time >>> symmetric, yet the universe is grossly asymmetric in time. >>> Boltzmann >>> proposed that if you had a universe in a maximum entropy state, >>> say a >>> uniform gas, then given enough time, the gas would undergo >>> fluctuations >>> to regions of lower entropy. Sometimes, purely at random, clumps of >>> molecules would happen to form. Even more rarely, these clumps might >>> be >>> large and ordered. Given infinite time, one could even have an >>> entire >>> visible-universe worth of matter clump together in an ordered >>> fashion, >>> from which state it would then decay into higher entropy conditions. >>> Life >>> could evolve during this decay, observe the universe around it, and >>> find >>> itself in conditions much like our own. >>> >>> The Boltzmann Brain is a counter-argument, suggesting that the >>> universe >>> and everything else is redundant; all you need is a brain to form >>> via >>> a spontaneous random fluctuation, and to hold together long enough >>> to >>> engage in a few moments of conscious thought. Such a Boltzmann Brain >>> is >>> far more likely to form than an entire universe, hence the vast >>> majority >>> of conscious thoughts in such a model will be in Boltzmann Brains >>> and not >>> in brains in large un
Re: Boltzmann Brains, consciousness and the arrow of time
Bruno Marchal wrote: > > It seems to me that your reasoning illustrates well the problems with > physical supervenience and physicalism, and perhaps ASSA. > > In any case the Universal Dovetailer generates all such gaz universes > generating the Boltzmann brains. Now the probability that you are > implemented by a particular Boltzmann brain is null, as it is null for > any particular. With the comp supervenience you have to "attach" > consciousness on ALL the histories going through your computational > state. It is a sort of double cone of histories. Are you assuming time as fundamental here? If time is merely inferred then it seems that states of Bbs could fit into the inferred time sequence as well as states that arose in some other way. > > We cannot belong to the aleph_zero Boltzmann brains state, because, > from our first person (plural) point of views we already belongs to > the 2^aleph_zero "winning" (infinite) histories. (or comp is wrong). I don't understand the counting measure. Why are histories order 2^apleph_0? Brent > > This is a case for RSSA indeed. I think. Bb are reduced to the "usual" > white rabbits histories, with RSSA, it seems to me. > > Bruno > > > > On 31 Dec 2008, at 22:58, Hal Finney wrote: > >> Sometimes we consider here the nature of consciousness, whether >> observer >> moments need to be linked to one another, the role of causality in >> consciousness, etc. I thought of an interesting puzzle about Boltzmann >> Brains which offers a new twist to these questions. >> >> As most readers are aware, Boltzmann Brains relate to an idea of >> Boltzmann >> on how to explain the arrow of time. The laws of physics seem to be >> time >> symmetric, yet the universe is grossly asymmetric in time. Boltzmann >> proposed that if you had a universe in a maximum entropy state, say a >> uniform gas, then given enough time, the gas would undergo >> fluctuations >> to regions of lower entropy. Sometimes, purely at random, clumps of >> molecules would happen to form. Even more rarely, these clumps might >> be >> large and ordered. Given infinite time, one could even have an entire >> visible-universe worth of matter clump together in an ordered fashion, >> from which state it would then decay into higher entropy conditions. >> Life >> could evolve during this decay, observe the universe around it, and >> find >> itself in conditions much like our own. >> >> The Boltzmann Brain is a counter-argument, suggesting that the >> universe >> and everything else is redundant; all you need is a brain to form via >> a spontaneous random fluctuation, and to hold together long enough to >> engage in a few moments of conscious thought. Such a Boltzmann Brain >> is >> far more likely to form than an entire universe, hence the vast >> majority >> of conscious thoughts in such a model will be in Boltzmann Brains >> and not >> in brains in large universes. If we were tempted to explain the >> arrow of >> time in this way, we must accept that the universe is an illusion and >> that we are actually Boltzmann Brains, a conclusion which most people >> don't like. >> >> Now this scenario can be criticized in many ways, but I want to >> emphasize >> a couple of points which aren't always appreciated. The first is >> that the >> Boltzmann scenario, whether a whole universe or just a Brain is >> forming, >> is basically time symmetric. That means that if you saw a movie of a >> Boltzmann universe forming and then decaying back to random entropy, >> you would not be able to tell which way the movie was running, if it >> were to be reversed. (This is an unavoidable consequence of the time >> symmetry of the underlying physics.) It follows that while the >> universe >> is moving into the low-entropy state, it must be evolving backwards. >> That >> is, an observer from outside would see time appearing to run >> backwards. >> Eggs would un-scramble themselves, objects would fall upwards from the >> ground, ripples would converge on spots in lakes from which rocks >> would >> then leap from the water, and so on. >> >> At some point this time reversal effect would stop, and the universe >> would then proceed to evolve back into a high entropy state, now >> with time >> going "forwards". Now, the forward phase will not in general be an >> exact >> mirror image of the reverse, because of slight random fluctuations and >
Re: Boltzmann Brains, consciousness and the arrow of time
It seems to me that your reasoning illustrates well the problems with physical supervenience and physicalism, and perhaps ASSA. In any case the Universal Dovetailer generates all such gaz universes generating the Boltzmann brains. Now the probability that you are implemented by a particular Boltzmann brain is null, as it is null for any particular. With the comp supervenience you have to "attach" consciousness on ALL the histories going through your computational state. It is a sort of double cone of histories. We cannot belong to the aleph_zero Boltzmann brains state, because, from our first person (plural) point of views we already belongs to the 2^aleph_zero "winning" (infinite) histories. (or comp is wrong). This is a case for RSSA indeed. I think. Bb are reduced to the "usual" white rabbits histories, with RSSA, it seems to me. Bruno On 31 Dec 2008, at 22:58, Hal Finney wrote: > > Sometimes we consider here the nature of consciousness, whether > observer > moments need to be linked to one another, the role of causality in > consciousness, etc. I thought of an interesting puzzle about Boltzmann > Brains which offers a new twist to these questions. > > As most readers are aware, Boltzmann Brains relate to an idea of > Boltzmann > on how to explain the arrow of time. The laws of physics seem to be > time > symmetric, yet the universe is grossly asymmetric in time. Boltzmann > proposed that if you had a universe in a maximum entropy state, say a > uniform gas, then given enough time, the gas would undergo > fluctuations > to regions of lower entropy. Sometimes, purely at random, clumps of > molecules would happen to form. Even more rarely, these clumps might > be > large and ordered. Given infinite time, one could even have an entire > visible-universe worth of matter clump together in an ordered fashion, > from which state it would then decay into higher entropy conditions. > Life > could evolve during this decay, observe the universe around it, and > find > itself in conditions much like our own. > > The Boltzmann Brain is a counter-argument, suggesting that the > universe > and everything else is redundant; all you need is a brain to form via > a spontaneous random fluctuation, and to hold together long enough to > engage in a few moments of conscious thought. Such a Boltzmann Brain > is > far more likely to form than an entire universe, hence the vast > majority > of conscious thoughts in such a model will be in Boltzmann Brains > and not > in brains in large universes. If we were tempted to explain the > arrow of > time in this way, we must accept that the universe is an illusion and > that we are actually Boltzmann Brains, a conclusion which most people > don't like. > > Now this scenario can be criticized in many ways, but I want to > emphasize > a couple of points which aren't always appreciated. The first is > that the > Boltzmann scenario, whether a whole universe or just a Brain is > forming, > is basically time symmetric. That means that if you saw a movie of a > Boltzmann universe forming and then decaying back to random entropy, > you would not be able to tell which way the movie was running, if it > were to be reversed. (This is an unavoidable consequence of the time > symmetry of the underlying physics.) It follows that while the > universe > is moving into the low-entropy state, it must be evolving backwards. > That > is, an observer from outside would see time appearing to run > backwards. > Eggs would un-scramble themselves, objects would fall upwards from the > ground, ripples would converge on spots in lakes from which rocks > would > then leap from the water, and so on. > > At some point this time reversal effect would stop, and the universe > would then proceed to evolve back into a high entropy state, now > with time > going "forwards". Now, the forward phase will not in general be an > exact > mirror image of the reverse, because of slight random fluctuations and > the like, but it will be an alternate path that essentially starts > with > the same initial conditions. So we will see one path backwards into > the > minimum-entropy state, and another path forwards from that state. Both > paths are fully plausible histories and neither is distinguishable > from > the other as far as which was reversed and which was forward, if you > ran a recording of the whole process backwards. > > One might ask, what causes time to run backwards during the first > half of > the Boltzmann scenario? The answer is, nothing but very, very odd > luck. > Time is no more likely to continue to run backwards, or to run >
Re: Boltzmann Brains, consciousness and the arrow of time
2009/1/1 "Hal Finney" : > I want to emphasize that this picture of how Boltzmann fluctuations would > work is a consquence of the laws of thermodynamics, and time symmetry. > Sometimes people imagine that the fluctuation into the Boltzmann > low-entropy state is fundamentally different from the fluctuation out > of it. They accept that the fluctuation out will be similar to our own > existence, with complex events happening. But they imagine that the > fluctuation into low entropy might be much simpler, molecules simply > aggregating together into some convenient state from which the complex > fluctuation out and back to chaos can begin. While this is not impossible > and hence will happen occasionally among the infinity of fluctuations in > the Boltzmann universe, it will be rare. It will be no more common for a > "simple" fluctation-in process to occur than for a simple fluctuation-out > process. In our universe, knowing it will evolve to a chaotic heat > death, we might imagine that molecules would just fly apart into chaos, > but we know that is highly unlikely. Instead, by far the most likely > path is a complex one, full of turbulence and reactions and similar > activity. By time symmetry, exactly the same arguments apply during > the fluctation-in phase. The vast majority of Boltzmann fluctuations > that achieve a particular degree of low entropy will do so via complex, > turbulent paths which if viewed in reverse will appear to be perfectly > plausible sequences of events for a universe which is decaying from > order to disorder, like our own. This is an interesting idea. I had imagined that the fluctuations in the decreasing entropy or winding up direction would involve chaotic aggregation of matter which would then wind down in a more organised way, giving rise to stars and planets and so on, but as you point out there is no reason to assume this. I am not sure why you suggest that the winding up direction lacks causality (leading to your question about whether it could give rise to consciousness): if all the air in the room moved to one side because, with incredible luck, the molecules all vibrated in the same direction for a few seconds should this event be called acausal? If we are conscious in winding up direction and winding up is no less likely to occur though interesting pathways than winding down, this would imply that at any point, we have about an equal chance of living in the winding up as the winding down phase: we would have no way of knowing. This would be the case whether we are ordinary brains or Boltzmann Brains, since in either case there has to be a winding up before the winding down can happen. A further implication is that there will be far more observer moments in the later stages of the universe than in the earlier stages. This is because unlikely as it is that the universe will wind up all the way to January 1st 2009, it is even less likely to continue winding up to 31st December 2008 (it is far more likely of course to only wind back to a state near the heat death end times, but there are less likely to be observers there). If you support the ASSA, that would imply that you are near your last moment of consciousness, since OM's later in your life have a much higher measure than earlier ones. Under the RSSA or if you take into account Boltzmann Brains that would not be a problem. -- Stathis Papaioannou --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-l...@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 -~--~~~~--~~--~--~---
Re: Boltzmann Brains, consciousness and the arrow of time
Hal Finney wrote: Sometimes we consider here the nature of consciousness, whether observer moments need to be linked to one another, the role of causality in consciousness, etc. I thought of an interesting puzzle about Boltzmann Brains which offers a new twist to these questions. As most readers are aware, Boltzmann Brains relate to an idea of Boltzmann on how to explain the arrow of time. The laws of physics seem to be time symmetric, yet the universe is grossly asymmetric in time. Boltzmann proposed that if you had a universe in a maximum entropy state, say a uniform gas, then given enough time, the gas would undergo fluctuations to regions of lower entropy. Sometimes, purely at random, clumps of molecules would happen to form. Even more rarely, these clumps might be large and ordered. Given infinite time, one could even have an entire visible-universe worth of matter clump together in an ordered fashion, from which state it would then decay into higher entropy conditions. Life could evolve during this decay, observe the universe around it, and find itself in conditions much like our own. The Boltzmann Brain is a counter-argument, suggesting that the universe and everything else is redundant; all you need is a brain to form via a spontaneous random fluctuation, and to hold together long enough to engage in a few moments of conscious thought. Such a Boltzmann Brain is far more likely to form than an entire universe, hence the vast majority of conscious thoughts in such a model will be in Boltzmann Brains and not in brains in large universes. If we were tempted to explain the arrow of time in this way, we must accept that the universe is an illusion and that we are actually Boltzmann Brains, a conclusion which most people don't like. Now this scenario can be criticized in many ways, but I want to emphasize a couple of points which aren't always appreciated. The first is that the Boltzmann scenario, whether a whole universe or just a Brain is forming, is basically time symmetric. That means that if you saw a movie of a Boltzmann universe forming and then decaying back to random entropy, you would not be able to tell which way the movie was running, if it were to be reversed. (This is an unavoidable consequence of the time symmetry of the underlying physics.) It follows that while the universe is moving into the low-entropy state, it must be evolving backwards. That is, an observer from outside would see time appearing to run backwards. Eggs would un-scramble themselves, objects would fall upwards from the ground, ripples would converge on spots in lakes from which rocks would then leap from the water, and so on. At some point this time reversal effect would stop, and the universe would then proceed to evolve back into a high entropy state, now with time going "forwards". Now, the forward phase will not in general be an exact mirror image of the reverse, because of slight random fluctuations and the like, but it will be an alternate path that essentially starts with the same initial conditions. So we will see one path backwards into the minimum-entropy state, and another path forwards from that state. Both paths are fully plausible histories and neither is distinguishable from the other as far as which was reversed and which was forward, if you ran a recording of the whole process backwards. One might ask, what causes time to run backwards during the first half of the Boltzmann scenario? The answer is, nothing but very, very odd luck. Time is no more likely to continue to run backwards, or to run backwards the same everywhere in the local fluctuation-area, than it is to start running backwards right now in the universe around you. Nothing stops eggs from unscrambling themselves except the unlikelihood, and the same principle is at work during the Boltzmann time-reversal phase. It is merely that we select, out of the infinity of time, those rare occasions where time does in fact "happen to happen" like this, that allows us to discuss it. I want to emphasize that this picture of how Boltzmann fluctuations would work is a consquence of the laws of thermodynamics, and time symmetry. Sometimes people imagine that the fluctuation into the Boltzmann low-entropy state is fundamentally different from the fluctuation out of it. They accept that the fluctuation out will be similar to our own existence, with complex events happening. But they imagine that the fluctuation into low entropy might be much simpler, molecules simply aggregating together into some convenient state from which the complex fluctuation out and back to chaos can begin. While this is not impossible and hence will happen occasionally among the infinity of fluctuations in the Boltzmann universe, it will be rare. It will be no more common for a "simple" fluctation-in process to occur than for a simple fluctuation-out process. In our universe, knowing it will evolve to a chaotic heat death, we mig
Boltzmann Brains, consciousness and the arrow of time
Sometimes we consider here the nature of consciousness, whether observer moments need to be linked to one another, the role of causality in consciousness, etc. I thought of an interesting puzzle about Boltzmann Brains which offers a new twist to these questions. As most readers are aware, Boltzmann Brains relate to an idea of Boltzmann on how to explain the arrow of time. The laws of physics seem to be time symmetric, yet the universe is grossly asymmetric in time. Boltzmann proposed that if you had a universe in a maximum entropy state, say a uniform gas, then given enough time, the gas would undergo fluctuations to regions of lower entropy. Sometimes, purely at random, clumps of molecules would happen to form. Even more rarely, these clumps might be large and ordered. Given infinite time, one could even have an entire visible-universe worth of matter clump together in an ordered fashion, from which state it would then decay into higher entropy conditions. Life could evolve during this decay, observe the universe around it, and find itself in conditions much like our own. The Boltzmann Brain is a counter-argument, suggesting that the universe and everything else is redundant; all you need is a brain to form via a spontaneous random fluctuation, and to hold together long enough to engage in a few moments of conscious thought. Such a Boltzmann Brain is far more likely to form than an entire universe, hence the vast majority of conscious thoughts in such a model will be in Boltzmann Brains and not in brains in large universes. If we were tempted to explain the arrow of time in this way, we must accept that the universe is an illusion and that we are actually Boltzmann Brains, a conclusion which most people don't like. Now this scenario can be criticized in many ways, but I want to emphasize a couple of points which aren't always appreciated. The first is that the Boltzmann scenario, whether a whole universe or just a Brain is forming, is basically time symmetric. That means that if you saw a movie of a Boltzmann universe forming and then decaying back to random entropy, you would not be able to tell which way the movie was running, if it were to be reversed. (This is an unavoidable consequence of the time symmetry of the underlying physics.) It follows that while the universe is moving into the low-entropy state, it must be evolving backwards. That is, an observer from outside would see time appearing to run backwards. Eggs would un-scramble themselves, objects would fall upwards from the ground, ripples would converge on spots in lakes from which rocks would then leap from the water, and so on. At some point this time reversal effect would stop, and the universe would then proceed to evolve back into a high entropy state, now with time going "forwards". Now, the forward phase will not in general be an exact mirror image of the reverse, because of slight random fluctuations and the like, but it will be an alternate path that essentially starts with the same initial conditions. So we will see one path backwards into the minimum-entropy state, and another path forwards from that state. Both paths are fully plausible histories and neither is distinguishable from the other as far as which was reversed and which was forward, if you ran a recording of the whole process backwards. One might ask, what causes time to run backwards during the first half of the Boltzmann scenario? The answer is, nothing but very, very odd luck. Time is no more likely to continue to run backwards, or to run backwards the same everywhere in the local fluctuation-area, than it is to start running backwards right now in the universe around you. Nothing stops eggs from unscrambling themselves except the unlikelihood, and the same principle is at work during the Boltzmann time-reversal phase. It is merely that we select, out of the infinity of time, those rare occasions where time does in fact "happen to happen" like this, that allows us to discuss it. I want to emphasize that this picture of how Boltzmann fluctuations would work is a consquence of the laws of thermodynamics, and time symmetry. Sometimes people imagine that the fluctuation into the Boltzmann low-entropy state is fundamentally different from the fluctuation out of it. They accept that the fluctuation out will be similar to our own existence, with complex events happening. But they imagine that the fluctuation into low entropy might be much simpler, molecules simply aggregating together into some convenient state from which the complex fluctuation out and back to chaos can begin. While this is not impossible and hence will happen occasionally among the infinity of fluctuations in the Boltzmann universe, it will be rare. It will be no more common for a "simple" fluctation-in process to occur than for a simple fluctuation-out process. In our universe, knowing it will evolve to a chaotic heat death, we might imagine that molecules
Re: Cosmology and Boltzmann brains
On 19 Jun 2008, at 02:51, Brent Meeker wrote: > > Günther Greindl wrote: >> Brent, >> >>> scientific theory. Occams razor is a vague desiderata. You can >>> justify >>> almost anything by choosing your definition of "complex", e.g. >>> theists >>> say, "God did it." is the simplest possible theory. >> >> no you can't: >> http://www.overcomingbias.com/2007/09/occams-razor.html >> > [...] > But I agree that the problem with God or The Witch as a theory is > that they > can explain anything and so fail to explain at all. It all depends of your theory or theology. If by God you mean the creationist God who build the world 6000 years ago, then you get an ad hoc theory, which nevertheless can be taken as a falsifiable explanation. This is exactly Vic's Stenger point and I agree with him. Not only such a theory is falsifiable, but it can be considered as having been falsified and has been wisely abandoned by any reasonable scientist since. This is where I agree again with Vic Stenger. [aparte: ... and given that some creationist asks for a course on "creationism" at school, then I think that creationnism should indeed be taught at school in the introduction to biology and evolution so that the failure of that theory is well explained, and here Vic Stenger's book can be very useful indeed. The creationist God is not supported by the facts]. If by God you mean the physical universe, and by "it", the physical universe, then indeed, as a theory, this explains the existence of the physical universe in a trivial way, so this does not explain the existence of the physical universe. If by God you mean the physical universe, and by "it" you mean "consciousness", then you get a falsifiable theory, which is indeed falsified in all the computationalist theories (by UDA). If by God you mean "arithmetical or mathematical truth" then you get a falsifiable theory of both consciousness and of the conscious appearance of physical (observable) universes. The theory predicts the existence of non trivial third person sharable probabilistic interfering dreams (subjective experiences) and is today well sustained by facts and logic. Indeed QM confirms its most counter- intuitive statements. But tomorrow it could been falsified as well. That is not obvious at all, but follows again by UDA. 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 [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
Günther Greindl wrote: > Brent, > >> scientific theory. Occams razor is a vague desiderata. You can justify >> almost anything by choosing your definition of "complex", e.g. theists >> say, "God did it." is the simplest possible theory. > > no you can't: > http://www.overcomingbias.com/2007/09/occams-razor.html > > most relevant quote from the above post: > > This lets us see clearly the problem with using "The lady down the > street is a witch; she did it" to explain the pattern in the sequence > "0101010101". If you're sending a message to a friend, trying to > describe the sequence you observed, you would have to say: "The lady > down the street is a witch; she made the sequence come out 0101010101." > Your accusation of witchcraft wouldn't let you shorten the rest of the > message; you would still have to describe, in full detail, the data > which her witchery caused. > > Witchcraft may fit our observations in the sense of qualitatively > permitting them; but this is because witchcraft permits everything, like > saying "Phlogiston!" So, even after you say "witch", you still have to > describe all the observed data in full detail. You have not compressed > the total length of the message describing your observations by > transmitting the message about witchcraft; you have simply added a > useless prologue, increasing the total length. > > The real sneakiness was concealed in the word "it" of "A witch did it". > A witch did what? > > QUOTE END > > same goes for "god did it" > > Cheers, > Günther > That's a computer scientist's idea of explanation, a definite description. In fact you can use an ostensive definition, "That.", while pointing and no description is needed. "The witch did it." is a casual explanation, not a description, and a casual explanation is often the kind needed since it tells you something you can do to change "That", e.g. "kill the witch". But I agree that the problem with God or The Witch as a theory is that they can explain anything and so fail to explain at all. Brent --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
Brent, > scientific theory. Occams razor is a vague desiderata. You can justify > almost anything by choosing your definition of "complex", e.g. theists > say, "God did it." is the simplest possible theory. no you can't: http://www.overcomingbias.com/2007/09/occams-razor.html most relevant quote from the above post: This lets us see clearly the problem with using "The lady down the street is a witch; she did it" to explain the pattern in the sequence "0101010101". If you're sending a message to a friend, trying to describe the sequence you observed, you would have to say: "The lady down the street is a witch; she made the sequence come out 0101010101." Your accusation of witchcraft wouldn't let you shorten the rest of the message; you would still have to describe, in full detail, the data which her witchery caused. Witchcraft may fit our observations in the sense of qualitatively permitting them; but this is because witchcraft permits everything, like saying "Phlogiston!" So, even after you say "witch", you still have to describe all the observed data in full detail. You have not compressed the total length of the message describing your observations by transmitting the message about witchcraft; you have simply added a useless prologue, increasing the total length. The real sneakiness was concealed in the word "it" of "A witch did it". A witch did what? QUOTE END same goes for "god did it" Cheers, Günther -- Günther Greindl Department of Philosophy of Science University of Vienna [EMAIL PROTECTED] http://www.univie.ac.at/Wissenschaftstheorie/ Blog: http://dao.complexitystudies.org/ Site: http://www.complexitystudies.org --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
Russell Standish wrote: > On Tue, Jun 17, 2008 at 09:24:21PM -0700, Brent Meeker wrote: > >>> scientific theories (doing so by definition). The reason it is >>> rejected is because of the arbitrary nature of the date makes it a >>> more complex theory (in the Occam's razor sense). >>> >> And it is not POVI. >> >> Brent Meeker >> >> > > True, but then POVI is a specialised version of Occams razor. > > It is more specific and as Vic argues it is sine qua non for a scientific theory. Occams razor is a vague desiderata. You can justify almost anything by choosing your definition of "complex", e.g. theists say, "God did it." is the simplest possible theory. Brent --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
On Tue, Jun 17, 2008 at 09:24:21PM -0700, Brent Meeker wrote: > > scientific theories (doing so by definition). The reason it is > > rejected is because of the arbitrary nature of the date makes it a > > more complex theory (in the Occam's razor sense). > > And it is not POVI. > > Brent Meeker > True, but then POVI is a specialised version of Occams razor. -- A/Prof Russell Standish Phone 0425 253119 (mobile) Mathematics UNSW SYDNEY 2052 [EMAIL PROTECTED] Australiahttp://www.hpcoders.com.au --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
Russell Standish wrote: > On Sun, Jun 15, 2008 at 01:40:09AM -0700, Greg Egan wrote: ... >>> But we do this all the time. Why is it we reject crackpot claims that >>> the world will end on such and such a date for instance? >> We reject those claims because they flow from theories that we reason >> should have led to observable consequences in the past (e.g. theories >> of interventionist deities). So what we have are prior probabilities >> that strongly disfavour those crackpot theories -- and given equal >> crackpot ratings, their predictions about the future are irrelevant. >> If crackpot A tells me that the world will end in 2012, and crackpot B >> tells me that the world will end in 20,012, then all else being equal >> I will (in 2008) give them both *equal* low credence. >> > > I was actually thinking more of theories like "the law of gravity will > be suspended on the 25th of July, 2012, but otherwise everything else > is the same". Obviously it makes the same retrodictions as our usual > scientific theories (doing so by definition). The reason it is > rejected is because of the arbitrary nature of the date makes it a > more complex theory (in the Occam's razor sense). And it is not POVI. Brent Meeker --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
Hi Greg, > > Thanks very much, everyone, for an interesting discussion, and thanks > for your patience towards someone who hasn't read your previous > debates on these issues. You are welcome Greg. > > I hope to find time to follow up all the links people gave. Russell, > that link to the "Everything Wiki" currently gives a 403. Don't hesitate to ask any question or make any remark if interested. Best, 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 [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
Sorry about that. It seems one needs the stuff after the domain - try http://everythingwiki.gcn.cx/wiki/index.php?title=Main_Page Cheers On Sun, Jun 15, 2008 at 07:34:39PM -0700, Greg Egan wrote: > > Thanks very much, everyone, for an interesting discussion, and thanks > for your patience towards someone who hasn't read your previous > debates on these issues. > > I hope to find time to follow up all the links people gave. Russell, > that link to the "Everything Wiki" currently gives a 403. > -- A/Prof Russell Standish Phone 0425 253119 (mobile) Mathematics UNSW SYDNEY 2052 [EMAIL PROTECTED] Australiahttp://www.hpcoders.com.au --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
Thanks very much, everyone, for an interesting discussion, and thanks for your patience towards someone who hasn't read your previous debates on these issues. I hope to find time to follow up all the links people gave. Russell, that link to the "Everything Wiki" currently gives a 403. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
On Sun, Jun 15, 2008 at 01:40:09AM -0700, Greg Egan wrote: > > > My attributes (eg > > height, weight and so on) are all drawn from distributions of such > > attributes. Why not some hypothetical property like "observer class" > > as set up in this toy problem? > > Why is your height and weight drawn from a certain distribution? It's > because you've been exposed to certain statistical influences on those > attributes, and those influences are influences that you have in > common with a certain subset of the human population. Of course. That was my point about it not being an actual sampling process. > But it would be > absurd to say that *your* height and weight is drawn from the > distribution of heights and weights of all living creatures in the > history of the universe. Equally, it would be absurd to say that your > observer class has been drawn from the distribution of all observers > in the history of the universe. > It is absurd to say we're drawn from a distribution over all living creatures. But it is not absurd to say we're drawn from a distribution over all conscious things. That is the essence of anthropic reasoning. It seems we're destined to disagree on this. > > But we do this all the time. Why is it we reject crackpot claims that > > the world will end on such and such a date for instance? > > We reject those claims because they flow from theories that we reason > should have led to observable consequences in the past (e.g. theories > of interventionist deities). So what we have are prior probabilities > that strongly disfavour those crackpot theories -- and given equal > crackpot ratings, their predictions about the future are irrelevant. > If crackpot A tells me that the world will end in 2012, and crackpot B > tells me that the world will end in 20,012, then all else being equal > I will (in 2008) give them both *equal* low credence. > I was actually thinking more of theories like "the law of gravity will be suspended on the 25th of July, 2012, but otherwise everything else is the same". Obviously it makes the same retrodictions as our usual scientific theories (doing so by definition). The reason it is rejected is because of the arbitrary nature of the date makes it a more complex theory (in the Occam's razor sense). > And given two (non-crackpot) cosmological theories with equal > grounding in modern physics and which imply no observable differences > up to the present epoch, but wildly different consequences in the very > far future, we *cannot* use those far-future consequences to > discriminate between them. Specifically, we cannot use differences in > the numbers of future observers in various classes that the different > theories predict, in order to favour one theory over another, here and > now. Actually, I think this statement follows as a consequence of the RSSA which Bruno mentioned earlier, in as far as we're discussing the future of our universe (rather than all possible universes). There is some discussion in my book "Theory of Nothing" about the RSSA versus its main competitor the ASSA. Also http://everythingwiki.gcn.cx/. Cheers -- A/Prof Russell Standish Phone 0425 253119 (mobile) Mathematics UNSW SYDNEY 2052 [EMAIL PROTECTED] Australiahttp://www.hpcoders.com.au --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
Hi Greg,
On 15 Jun 2008, at 10:40, Greg Egan wrote:
>>
>> My attributes (eg
>> height, weight and so on) are all drawn from distributions of such
>> attributes. Why not some hypothetical property like "observer class"
>> as set up in this toy problem?
>
> Why is your height and weight drawn from a certain distribution? It's
> because you've been exposed to certain statistical influences on those
> attributes, and those influences are influences that you have in
> common with a certain subset of the human population. But it would be
> absurd to say that *your* height and weight is drawn from the
> distribution of heights and weights of all living creatures in the
> history of the universe. Equally, it would be absurd to say that your
> observer class has been drawn from the distribution of all observers
> in the history of the universe.
I agree, and I think one half of the everything-list participants
agree on this (cf our Relative versus Absolute Self-Sample Assumption
debates). The probabilities are relatively conditioned on the "brain/
body" states *histories*, and things are not so different from
Feynman integral formulation of QM.
Now, the question is "why *quantum* histories". My point is that if we
assume we are turing-emulable, then the probabilities have to be
derived from a sum on *all* computations. Not just the quantum one.
This means we can test the computationalist theory by comparing the
sum on all quantum histories/computations (with its weird probability/
amplitude relation) and the sum on all histories/computations.
At first sight the comp theory is false because it leads to many more
white rabbits than the quantum, but by taking into account constraints
related to incompleteness phenomena and logic of self-references,
there are (rather technical alas) evidences that the third person
white rabbits go away too.
It remains abnormally too much first person white rabbits, and I am a
bit stuck on that. QM, and physics in general, per se, does not even
address those first person purely qualia rabbits (although Galileo,
Einstein, Boscovitch, Everett, .Wheeler, Rossler, ... can be seen as a
sequences of physicists converging to that.
Assuming we are turing emulable, we have to "radicalize" Everett. We
have to justify why, in appearance, the QM computations wins in the
observable game. All the pieces of the puzzle are there.
Greg, I have read and appreciate very much your "Permutation City"
novel, but to be honest, I see you still believe "physics" study what
there is. This seems to prevent you to follow your own logical line.
See my Sane04 paper for an argument (in english) showing that IF we
are turing emulable, THEN the observable is just what emerges from all
possible local merging and differentiations of computational histories
(= as seen as first person point of view, probably plural first
person. Merging works through amnesia, and I don't explicitly tackle
merging in my publications).
In "Laws without Laws", or "It from bits" John Archibald Wheeler got
that point: the physical laws emerges on something non-physical.
Assuming we are digital machine, that non-physical stuff has not to be
more than the additive and multiplicative properties of natural
numbers. Poetically: what we take for being the physical reality is in
fact the border of the ignorance of self-introspecting universal
machine/number ("us"). That "Ignorance" is *very* big, and productive,
almost "alive" when seen from inside. And mathematically tractable by
computer science/recursion theory.
To sum up in a Soccer way: Plato 1, Aristotle 0. (I don't pretend the
match is over!)
But I think a lot that QM confirms already the comp hypothesis, and
the non-materiality of matter.
To sum up in a Kronecker's way: God creates the natural numbers, all
the rest are web of coherent (and less coherent) dreams by natural
numbers.
I think I have an argument showing that the comp hyp reduces the mind-
body problem into a pure body problem. The problem now is that most
physicist takes bodies from granted, and this prevents the
understanding of the argument. But that is "religion".
(For example, Vic Stenger in his "God, the failed hypothesis"
identifies material with natural, and immaterial with supernatural,
making math and logic, what? parapsychology? Theology perhaps. At
least physicists like Penrose, Wheeler, Deutch, Tegmark are aware of
the mathematical reality. Only logicians seems to be aware of (and
familiar with) the intricacy of digital self-reference. It is pity
that the gap between logicians, physicists and philosopher of mind/
theologian remain so wide. At more than one level, I'm afraid. I am
quite opposed to creationism and any "authoritative" bible-god
crackpot theology, but many scientists aggravate the hiatus by being a
bit dogmatic on matter like if we would have solved the mind-body
problem. My modest work, an
Re: Cosmology and Boltzmann brains
On Jun 15, 1:27 pm, Russell Standish <[EMAIL PROTECTED]> wrote: > What sparked our/my interest is that you seemed to have > interesting argument against the use of anthropic reasoning. I'm certainly not arguing against *all* anthropic reasoning; every argument needs to be examined on a case by case basis. > However, > on reflection it seems to boil down to "there is no mysterious > pre-world of souls hanging around waiting the be born, so there is no > distribution of observers to be sampled from". I disagree with this syllogism. This is where reasoning about conventional cosmology departs from reasoning about all-universe models. In the latter context, it might make sense to consider "myself, right now" as comprising a vast number of instances who have identical current experiences, but whose next experience will be different for different instances. I might then concern myself with adopting a strategy that will benefit a majority of my instances, and which can exploit the fact that those instances, in their totality, obey some distribution. In that context, there certainly is a distribution of observers to be sampled from. But in conventional cosmology, although observers of this form are a possibility, they're not a given. If I really am living, solely, on one particular planet at one particular time, then I have never sampled the distribution of all observers in the history of the universe, and nothing about my experience can tell me anything about that distribution (beyond the fact that I, and my fellow humans, belong to it). > Assuming for the sake of argument that I can be viewed as a random > sample of the global population, how does this actually help to > distinguish theory A or B, unless I actually received less than X > kJ/day, which, by assumption is not the case. I don't see how > anthropic reasoning makes a difference in this case. I probably haven't made my point very clearly here. What I'm arguing against is what you wrote previously: > My attributes (eg > height, weight and so on) are all drawn from distributions of such > attributes. Why not some hypothetical property like "observer class" > as set up in this toy problem? Why is your height and weight drawn from a certain distribution? It's because you've been exposed to certain statistical influences on those attributes, and those influences are influences that you have in common with a certain subset of the human population. But it would be absurd to say that *your* height and weight is drawn from the distribution of heights and weights of all living creatures in the history of the universe. Equally, it would be absurd to say that your observer class has been drawn from the distribution of all observers in the history of the universe. > > Ultimately this boils down to locality. I, here and now, do not know > > the future, so of course I can't discriminate between rival theories > > that make identical predictions about the present but different > > predictions about the future. > > But we do this all the time. Why is it we reject crackpot claims that > the world will end on such and such a date for instance? We reject those claims because they flow from theories that we reason should have led to observable consequences in the past (e.g. theories of interventionist deities). So what we have are prior probabilities that strongly disfavour those crackpot theories -- and given equal crackpot ratings, their predictions about the future are irrelevant. If crackpot A tells me that the world will end in 2012, and crackpot B tells me that the world will end in 20,012, then all else being equal I will (in 2008) give them both *equal* low credence. And given two (non-crackpot) cosmological theories with equal grounding in modern physics and which imply no observable differences up to the present epoch, but wildly different consequences in the very far future, we *cannot* use those far-future consequences to discriminate between them. Specifically, we cannot use differences in the numbers of future observers in various classes that the different theories predict, in order to favour one theory over another, here and now. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
On Sat, Jun 14, 2008 at 07:56:21PM -0700, Greg Egan wrote: > > Hi Russell, thanks very much for your reply. > > It's possible that I'm arguing at cross-purposes here, because I > gather that the whole reason for this list is to discuss models of the > universe that are very different from standard cosmology, but I hope > you won't mind if I pursue a defence of my specific claims at the N- > Category Café, which are intended to apply to reasoning about standard > cosmology. Not at all. What sparked our/my interest is that you seemed to have interesting argument against the use of anthropic reasoning. However, on reflection it seems to boil down to "there is no mysterious pre-world of souls hanging around waiting the be born, so there is no distribution of observers to be sampled from". I disagree with this syllogism. ... > For example, suppose an Australian health statistician is forbidden to > leave Australia or to access data collected elsewhere, and that there > is no migration between countries. Then the *global* distributions of > human height and weight become completely invisible to her, and > completely irrelevant to a child growing up in Australia. > > Suppose theory A claims that children who receive less than X > kilojoules a day will all have a height of less than 120 cm at age 15, > while theory B claims that half of these malnourished children will > nonetheless exceed 120 cm at age 15. I currently have no reason to > prefer theory A over theory B, but I'd like to gather some empirical > data to see which one is right. > > But suppose I have access only to data about Australia, and it so > happens than in Australia, there are *no* children who receive less > than X kilojoules a day. Then it doesn't matter what I do or how I > reason, I am never going to have a justification to distinguish > between theory A and theory B. Noticing, say, that my own height > would have different relative frequencies in the global population > under the two theories is not informative, because there is no > relevant sense in which I can be viewed as a random sample of the > global population. Assuming for the sake of argument that I can be viewed as a random sample of the global population, how does this actually help to distinguish theory A or B, unless I actually received less than X kJ/day, which, by assumption is not the case. I don't see how anthropic reasoning makes a difference in this case. > > A cosmologist who hopes to distinguish between cosmological theories > based on their predictions about future populations of Boltzmann > brains is in exactly the same situation. The data to which she has > access does not discriminate between the theories. It is pointless > for her to note that one theory implies that the overwhelming majority > of observers in the history of the universe will be Boltzmann brains, > while another theory reverses the proportions; she simply does not > have access to the global populations in question. > In only having superficial knowledge of the BB argument (largely gleaned from New Scientist articles), I think I'll leave this one to more knowledgable people to comment. > > > Given that humans are class 2 observers, all we have is the fact H: > > > > >H := "The number of class 2 observers in the history of the > > > universe is at least of the order 10^10." > > > > We also have the fact that I am of class 2. > > But there is no "also" here, because it is a necessary consequence of > H that someone exists who says "I am of class 2". To say "I am of > class 2" means no more and no less than: "The number of class 2 > observers in the history of the universe is at least 1." It does > *not* mean "Someone was picked at random from the set of all observers > who have ever lived, or ever will live, and was found to be class 2". > Again - I disagree. > Ultimately this boils down to locality. I, here and now, do not know > the future, so of course I can't discriminate between rival theories > that make identical predictions about the present but different > predictions about the future. But we do this all the time. Why is it we reject crackpot claims that the world will end on such and such a date for instance? Of course, one day, one of these guys might be proven right :) Good luck convincing the N-Category Cafe crowd. Cheers -- A/Prof Russell Standish Phone 0425 253119 (mobile) Mathematics UNSW SYDNEY 2052 [EMAIL PROTECTED] Australiahttp://www.hpcoders.com.au ---
Re: Cosmology and Boltzmann brains
Hi Russell, thanks very much for your reply. It's possible that I'm arguing at cross-purposes here, because I gather that the whole reason for this list is to discuss models of the universe that are very different from standard cosmology, but I hope you won't mind if I pursue a defence of my specific claims at the N- Category Café, which are intended to apply to reasoning about standard cosmology. On Jun 15, 8:45 am, Russell Standish <[EMAIL PROTECTED]> wrote: > On Fri, Jun 13, 2008 at 09:28:07PM -0700,Greg Egan wrote: > > The p(2|A) you give above is the probability for selecting one > > observer at random from the totality of all observers throughout the > > history of the universe, and finding that he/she/it belongs to class 2 > > (given theory A). But no such selection process has taken place. > > There may be no physical process doing the sampling like pulling balls > from an urn, but it is nevertheless a sampling. My attributes (eg > height, weight and so on) are all drawn from distributions of such > attributes. Why not some hypothetical property like "observer class" > as set up in this toy problem? Your height and weight can be understood as arising from a complicated sequence of local, causal processes and a set of assumptions about your initial conditions (at the very least, including the assumption that you are human). Whether some health statistician samples a sub- population to which you belong, or whether you, in the process of living your life, sample various probabilistic influences, the relevant distribution needs to be *accessible* for this way of looking at things to make sense. For example, suppose an Australian health statistician is forbidden to leave Australia or to access data collected elsewhere, and that there is no migration between countries. Then the *global* distributions of human height and weight become completely invisible to her, and completely irrelevant to a child growing up in Australia. Suppose theory A claims that children who receive less than X kilojoules a day will all have a height of less than 120 cm at age 15, while theory B claims that half of these malnourished children will nonetheless exceed 120 cm at age 15. I currently have no reason to prefer theory A over theory B, but I'd like to gather some empirical data to see which one is right. But suppose I have access only to data about Australia, and it so happens than in Australia, there are *no* children who receive less than X kilojoules a day. Then it doesn't matter what I do or how I reason, I am never going to have a justification to distinguish between theory A and theory B. Noticing, say, that my own height would have different relative frequencies in the global population under the two theories is not informative, because there is no relevant sense in which I can be viewed as a random sample of the global population. A cosmologist who hopes to distinguish between cosmological theories based on their predictions about future populations of Boltzmann brains is in exactly the same situation. The data to which she has access does not discriminate between the theories. It is pointless for her to note that one theory implies that the overwhelming majority of observers in the history of the universe will be Boltzmann brains, while another theory reverses the proportions; she simply does not have access to the global populations in question. > > Given that humans are class 2 observers, all we have is the fact H: > > >H := "The number of class 2 observers in the history of the > > universe is at least of the order 10^10." > > We also have the fact that I am of class 2. But there is no "also" here, because it is a necessary consequence of H that someone exists who says "I am of class 2". To say "I am of class 2" means no more and no less than: "The number of class 2 observers in the history of the universe is at least 1." It does *not* mean "Someone was picked at random from the set of all observers who have ever lived, or ever will live, and was found to be class 2". Ultimately this boils down to locality. I, here and now, do not know the future, so of course I can't discriminate between rival theories that make identical predictions about the present but different predictions about the future. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
Hi Greg, and welcome to the list. Your ears must be burning - you have
often been talked about here, always in a good light!
On Fri, Jun 13, 2008 at 09:28:07PM -0700, Greg Egan wrote:
>
> On Jun 13, 9:25 am, Russell Standish <[EMAIL PROTECTED]> wrote:
>
> > I'm not sure his application of Bayes is correct. Given the facts of
> > his hypothetical scenario, and writing e=10^{-4050}
> >
> > p(1|A) = e
> > p(2|A) = 1-e
> > p(1|B) = 1-e
> > p(2|B) = e
> >
> > This is my translation of:
> >
> > "Now suppose that (somehow) we're able to extract the following (somewhat
> > fanciful) predictions: theory A implies that in the entire history of
> > the universe, there will be 10^50 observers* of class 1 and 10^5000
> > observers of class 2, while theory B implies that in the entire history of
> >the universe, there will be 10^5000 observers of class 1 and 10^50 observers
> >of class 2."
>
> Hi Russell
>
> The p(2|A) you give above is the probability for selecting one
> observer at random from the totality of all observers throughout the
> history of the universe, and finding that he/she/it belongs to class 2
> (given theory A). But no such selection process has taken place.
There may be no physical process doing the sampling like pulling balls
from an urn, but it is nevertheless a sampling. My attributes (eg
height, weight and so on) are all drawn from distributions of such
attributes. Why not some hypothetical property like "observer class"
as set up in this toy problem?
Of course, in reality, there may be no well defined meaning to terms
like p(2|A), particularly if, as I suspect, observer moments satisfy a
complex valued measure. However, in this toy problem you presented,
the terms are well defined.
> Given that humans are class 2 observers, all we have is the fact H:
>
>H := "The number of class 2 observers in the history of the
> universe is at least of the order 10^10."
>
We also have the fact that I am of class 2.
> (We could argue that this ought to be somewhat higher than 10^10,
> depending on how we classify our ancestors, but the point is that any
> reasonable number we pick will be less than 10^50. And of course this
> whole scenario is just a toy model for the sake of having a concrete
> example to discuss.)
>
> We then have:
>
> P(H|A) = P(H|B) = 1
> P(A) = P(B) = 1/2
> P(H) = P(A) P(H|A) + P(B) P(H|B) = 1
>
> P(A|H) = P(H|A) P(A) / P(H) = 1/2
> P(B|H) = P(H|B) P(B) / P(H) = 1/2
>
> In other words, the data we have, expressed in the observation H, does
> nothing to discriminate between theory A and theory B, and leaves the
> initial prior probabilities unchanged.
>
H does not discriminate, but 2 (I am of class 2) does. And all the
result does is give a preference to theory A rather than B, assuming
no prior preference (eg Occams razor).
> We, in the here and now, have no access to any process that randomly
> samples the set of all observers in the history of the universe. Of
> course it's possible to construct various sums over the set of *all*
> observers and seek to maximise some kind of global average, and to ask
> questions such as "What strategy, if adopted uniformly by every single
> observer in the history of the universe, would maximise the
> expectation value for the number of observers in the history of the
> universe who correctly guessed whether A or B was the true description
> of the universe." But whether or not there are any plausible
> scenarios in which maximising that number could be a desirable
> goal ... the fact remains that if we're discussing the *information*
> available to *us* -- the human population of Earth at the present
> moment -- we do not have access to the probabilities p(1|A), p(2|A),
> p(1|B), p(2|B) that you describe.
>
That is largely what we do with applications of Occams razor. We
choose the simpler theory on the basis that it is more likely to
continue being right when tested with future observations.
> The context in which I was discussing this at the N-Category Café is
> the claim by some cosmologists that we ought to favour A-type
> cosmological theories in which class 2 observers like us, with a clear
> Darwinian history, will not be outnumbered (over the whole history of
> the universe) by class 1 observers (Boltzmann brains). My contention
> is that we have no empirical data at the present time that tells us
> anything at all about the relative frequencies (over the whole history
> of the universe) of class 1 and class 2 observers, and that our own
> existence should not be mistaken for the outcome of a random sampling
> of that whole-of-spacetime population. These issue
Re: Cosmology and Boltzmann brains
Hi Stathis, hi Greg, Le 14-juin-08, à 10:35, Stathis Papaioannou a écrit : > 2008/6/14 Greg Egan <[EMAIL PROTECTED]>: > >> The context in which I was discussing this at the N-Category Café is >> the claim by some cosmologists that we ought to favour A-type >> cosmological theories in which class 2 observers like us, with a clear >> Darwinian history, will not be outnumbered (over the whole history of >> the universe) by class 1 observers (Boltzmann brains). > > There is also the argument that the appearance of having a "clear > Darwinian history" is not necessarily evidence that we are not > Boltzmann brains. This is because the problem of what sort of > observers would be generated by Boltzmann brains reduces to the > problem of what sort of observers would be generated by the ensemble > of all possible observer moments, or all possible computations. That is the key point. And the notion of "all computations" makes sense once you take Church's thesis (alias: "Godel's miracle") seriously into account. And this leads to the use of theoretical computer science for finding the relative measure on the computations as expected by self-referentially correct machines or entities. This gives the prospect of deriving physics from numbers/programs in a spirit close to the "Darwinian" spirit. > How > such an ensemble might give rise to the orderly world we observe has > been one of the main topics of discussion on this list over the years. See my url below for the beginning of a solution. Indeed a quantum logic already appears in the self-referentially correct discourse of machine betting or anticipating their own consistent extensions extending the states generated by a Universal Dovetailer. What is crucial for understanding this consists in making clear how to distinguish the first and third person points of view. But the incompleteness theorems (applicable to any self-referentially correct entity in the sense of Godel Lob Smullyan etc.) provide all the needed nuances for translating in arithmetic such distinctions. The net result is counter-intuitive given that the physical universe can no more be a primary structure: it emerges from the coherence conditions which exist on the possible "machines' dreams'. (Note that the n-category theory seems to provide a framework to define (but not to motivate) such coherence conditions. Enough for getting knot theory and space (cf Yetter), but not yet physics (by lack of taking into account notions of person and the mind body problem in general). About the mind body problem, a persisting misunderstanding *seems* to remain between monist materialists and dualists, but as it has been discussed here for a while, if we bet we are support by digitalizable body-entity we have to expect monist immaterialism to be eventually correct. The 3-person basic immaterial entities being the numbers together with their additive and multiplicative structure (from this you already get "all computations" from the inside first person pov together with their ). Boltzman brains reminds me of Putnam Chalmers Mallah implementation problem. Real problems in a wrong frame. Those kind of problems are good pointers on the mind body problems though, but they postulate a physical reality which cannot be made primary if we take the idea that we are Turing emulable seriously enough. The problem is more a problem in the philosophy of mind and mathematics, than in physics. Plotinus' conception of reality remains the closer I heard about to the type of reality just logically coherent with computer science and logic, I think. Bruno http://iridia.ulb.ac.be/~marchal/ > (eg. see Russel's paper here: > http://www.journaloftheoretics.com/Links/Papers/ockham.pdf). > > > > -- > Stathis Papaioannou > > > > --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
2008/6/14 Greg Egan <[EMAIL PROTECTED]>: > The context in which I was discussing this at the N-Category Café is > the claim by some cosmologists that we ought to favour A-type > cosmological theories in which class 2 observers like us, with a clear > Darwinian history, will not be outnumbered (over the whole history of > the universe) by class 1 observers (Boltzmann brains). There is also the argument that the appearance of having a "clear Darwinian history" is not necessarily evidence that we are not Boltzmann brains. This is because the problem of what sort of observers would be generated by Boltzmann brains reduces to the problem of what sort of observers would be generated by the ensemble of all possible observer moments, or all possible computations. How such an ensemble might give rise to the orderly world we observe has been one of the main topics of discussion on this list over the years (eg. see Russel's paper here: http://www.journaloftheoretics.com/Links/Papers/ockham.pdf). -- Stathis Papaioannou --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
>> fanciful) predictions: theory A implies that in the entire history of >> the universe, there will be 10^50 observers* of class 1 and 10^5000 >> observers of class 2, while theory B implies that in the entire history of >> the universe, there will be 10^5000 observers of class 1 and 10^50 observers >> of class 2." >> > > Hi Russell > > The p(2|A) you give above is the probability for selecting one > observer at random from the totality of all observers throughout the > history of the universe, and finding that he/she/it belongs to class 2 > (given theory A). But no such selection process has taken place. > Given that humans are class 2 observers, all we have is the fact H: > >H := "The number of class 2 observers in the history of the > universe is at least of the order 10^10." > > (We could argue that this ought to be somewhat higher than 10^10, > depending on how we classify our ancestors, but the point is that any > reasonable number we pick will be less than 10^50. And of course this > whole scenario is just a toy model for the sake of having a concrete > example to discuss.) > > We then have: > > P(H|A) = P(H|B) = 1 > P(A) = P(B) = 1/2 > P(H) = P(A) P(H|A) + P(B) P(H|B) = 1 > > P(A|H) = P(H|A) P(A) / P(H) = 1/2 > P(B|H) = P(H|B) P(B) / P(H) = 1/2 > > In other words, the data we have, expressed in the observation H, does > nothing to discriminate between theory A and theory B, and leaves the > initial prior probabilities unchanged. > > We, in the here and now, have no access to any process that randomly > samples the set of all observers in the history of the universe. Of > course it's possible to construct various sums over the set of *all* > observers and seek to maximise some kind of global average, and to ask > questions such as "What strategy, if adopted uniformly by every single > observer in the history of the universe, would maximise the > expectation value for the number of observers in the history of the > universe who correctly guessed whether A or B was the true description > of the universe." But whether or not there are any plausible > scenarios in which maximising that number could be a desirable > goal ... the fact remains that if we're discussing the *information* > available to *us* -- the human population of Earth at the present > moment -- we do not have access to the probabilities p(1|A), p(2|A), > p(1|B), p(2|B) that you describe. > > The context in which I was discussing this at the N-Category Café is > the claim by some cosmologists that we ought to favour A-type > cosmological theories in which class 2 observers like us, with a clear > Darwinian history, will not be outnumbered (over the whole history of > the universe) by class 1 observers (Boltzmann brains). My contention > is that we have no empirical data at the present time that tells us > anything at all about the relative frequencies (over the whole history > of the universe) of class 1 and class 2 observers, and that our own > existence should not be mistaken for the outcome of a random sampling > of that whole-of-spacetime population. These issues are discussed in > more detail in: > > "Are We Typical?" by James Hartle and Mark Srednicki, > http://arxiv.org/abs/0704.2630 > > > --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
On Jun 13, 9:25 am, Russell Standish <[EMAIL PROTECTED]> wrote:
> I'm not sure his application of Bayes is correct. Given the facts of
> his hypothetical scenario, and writing e=10^{-4050}
>
> p(1|A) = e
> p(2|A) = 1-e
> p(1|B) = 1-e
> p(2|B) = e
>
> This is my translation of:
>
> "Now suppose that (somehow) we're able to extract the following (somewhat
> fanciful) predictions: theory A implies that in the entire history of
> the universe, there will be 10^50 observers* of class 1 and 10^5000 observers
> of class 2, while theory B implies that in the entire history of
>the universe, there will be 10^5000 observers of class 1 and 10^50 observers
>of class 2."
Hi Russell
The p(2|A) you give above is the probability for selecting one
observer at random from the totality of all observers throughout the
history of the universe, and finding that he/she/it belongs to class 2
(given theory A). But no such selection process has taken place.
Given that humans are class 2 observers, all we have is the fact H:
H := "The number of class 2 observers in the history of the
universe is at least of the order 10^10."
(We could argue that this ought to be somewhat higher than 10^10,
depending on how we classify our ancestors, but the point is that any
reasonable number we pick will be less than 10^50. And of course this
whole scenario is just a toy model for the sake of having a concrete
example to discuss.)
We then have:
P(H|A) = P(H|B) = 1
P(A) = P(B) = 1/2
P(H) = P(A) P(H|A) + P(B) P(H|B) = 1
P(A|H) = P(H|A) P(A) / P(H) = 1/2
P(B|H) = P(H|B) P(B) / P(H) = 1/2
In other words, the data we have, expressed in the observation H, does
nothing to discriminate between theory A and theory B, and leaves the
initial prior probabilities unchanged.
We, in the here and now, have no access to any process that randomly
samples the set of all observers in the history of the universe. Of
course it's possible to construct various sums over the set of *all*
observers and seek to maximise some kind of global average, and to ask
questions such as "What strategy, if adopted uniformly by every single
observer in the history of the universe, would maximise the
expectation value for the number of observers in the history of the
universe who correctly guessed whether A or B was the true description
of the universe." But whether or not there are any plausible
scenarios in which maximising that number could be a desirable
goal ... the fact remains that if we're discussing the *information*
available to *us* -- the human population of Earth at the present
moment -- we do not have access to the probabilities p(1|A), p(2|A),
p(1|B), p(2|B) that you describe.
The context in which I was discussing this at the N-Category Café is
the claim by some cosmologists that we ought to favour A-type
cosmological theories in which class 2 observers like us, with a clear
Darwinian history, will not be outnumbered (over the whole history of
the universe) by class 1 observers (Boltzmann brains). My contention
is that we have no empirical data at the present time that tells us
anything at all about the relative frequencies (over the whole history
of the universe) of class 1 and class 2 observers, and that our own
existence should not be mistaken for the outcome of a random sampling
of that whole-of-spacetime population. These issues are discussed in
more detail in:
"Are We Typical?" by James Hartle and Mark Srednicki,
http://arxiv.org/abs/0704.2630
--~--~-~--~~~---~--~~
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To post to this group, send email to [EMAIL PROTECTED]
To unsubscribe from this group, send email to [EMAIL PROTECTED]
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Re: Cosmology and Boltzmann brains
On Thu, Jun 12, 2008 at 11:43:26PM +0200, Günther Greindl wrote:
>
> Hi all,
>
> someone on another list alerted me to this post, there is a very
> interesting discussion going on on that blog related to Observer Moments:
>
> http://golem.ph.utexas.edu/category/2008/06/urban_myths_in_contemporary_co.html
>
> Greg Egan has posted too; and has some very interesting things to say.
> Specifically, he says the right things why DA fails:
I'm not sure his application of Bayes is correct. Given the facts of
his hypothetical scenario, and writing e=10^{-4050}
p(1|A) = e
p(2|A) = 1-e
p(1|B) = 1-e
p(2|B) = e
This is my translation of:
"Now suppose that (somehow) we\u2019re able to extract the following (somewhat
fanciful) predictions: theory A implies that in the entire history of the
universe, there will be 1050 observers* of class 1 and 105000 observers of
class 2, while theory B implies that in the entire history of the universe,
there will be 105000 observers of class 1 and 1050 observers of class 2."
Now we further suppose there is no reason to prefer theory A over B,
ie p(A)=p(B).
Then we need to compute the likelihood of theory A given the fact that
we're an observer of class 2, ie:
p(A|2) = p(A & 2) / p(2) = p(2|A) p(A) / p(2) ... (1)
and
p(B|2) = p(B & 2) / p(2) = p(2|B) p(B) / p(2) ... (2)
dividing (1) by (2) gives
p(A|2) / p(B|2) = p(2|A) / p(2|B) = (1-e) / e = 10^{4050}
ie Bayes' theorem most definitely implies theory A is overwhelmingly
supported.
Have I missed something, or is Greg Egan wrong?
In a later posting, he gives absurd example of some extremely
improbably theory A, and applying the above reasoning. Yet the above
reasoning assumes p(A)=p(B), which is not the case in his absurd
example. It may be relevant to the BB argument though. If theory A was
"we are a statistical fluctuation (ie Boltzmann brains)", and theory B
was "evolved by Darwinian evolution", then p(A) << p(B). One cannot
comment on whether one should prefer A or B, since the numerical
values are just pulled out of a hat in any case.
--
A/Prof Russell Standish Phone 0425 253119 (mobile)
Mathematics
UNSW SYDNEY 2052 [EMAIL PROTECTED]
Australiahttp://www.hpcoders.com.au
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Re: Cosmology and Boltzmann brains
On Fri, Jun 13, 2008 at 10:28:28AM +1000, Stathis Papaioannou wrote: > > Is the ensemble of observer moments generated by the postulated BB's > different from the ensemble of all possible observer moments? > I don't see how it could be different. AFAICT BBs are nothing other than the infamous white rabbit. Still I'm trying to digest Greg Egan's objections to the DA - not sure that I understand yet, but it has the flavour of a debate I had with someone else a couple of years ago on a-void (not sure, maybe Jonathan Colvin, but probably someone else). Cheers -- A/Prof Russell Standish Phone 0425 253119 (mobile) Mathematics UNSW SYDNEY 2052 [EMAIL PROTECTED] Australiahttp://www.hpcoders.com.au --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Cosmology and Boltzmann brains
2008/6/13 Günther Greindl <[EMAIL PROTECTED]>: > > Hi all, > > someone on another list alerted me to this post, there is a very > interesting discussion going on on that blog related to Observer Moments: > > http://golem.ph.utexas.edu/category/2008/06/urban_myths_in_contemporary_co.html Is the ensemble of observer moments generated by the postulated BB's different from the ensemble of all possible observer moments? -- Stathis Papaioannou --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Cosmology and Boltzmann brains
Hi all, someone on another list alerted me to this post, there is a very interesting discussion going on on that blog related to Observer Moments: http://golem.ph.utexas.edu/category/2008/06/urban_myths_in_contemporary_co.html Greg Egan has posted too; and has some very interesting things to say. Specifically, he says the right things why DA fails: http://golem.ph.utexas.edu/category/2008/06/urban_myths_in_contemporary_co.html#c017260 "The fact that an observer selected at random from the pool of all observers would be more likely to be class 2 under theory A is irrelevant; nobody has to “select us at random” before we’re allowed to make an observation." And here: http://golem.ph.utexas.edu/category/2008/06/urban_myths_in_contemporary_co.html#c017310 "There is one aspect of the BB argument that is independent of these issues, though; rather than debating whether far-future life will be “freakish” or “Darwinian”, if we accept an infinite or extremely long future in which observers of any kind are present – so long as they can make observations that show them that they are not living in the early universe – then “typicality” is not a matter of being a Boltzmann brain or a Darwinian brain, but simply whether you are living in the early universe or the later universe. The way the BB fans use probability, they would then argue that the universe is very unlikely to have this very long extended future, because then a “typical” observer would live in the far future … making us “atypical” because we live in the early universe. I guess that’s really just a variant of the infamous Doomsday argument, applied to the universe as a whole: the universe is unlikely to last very long, otherwise it would be “unlikely” for us to find ourselves so near the beginning. That’s where I think they’re simply misusing probability: we are not a random selection of observers taken from the entire history of the universe." That is what I think is the real problem with DA arguments: it is a decision strategy; but OM's are not playing games ;-); they do reasoning; and while this strategy would assure that most OM's are correct, it is not very satisfactory for the current OM - it only gains knowledge about optimal strategy, but not of it's _concrete_ situation. That is why I think RSSA is better than ASSA. But RSSA is still not satisfactory. Hmm; this whole continuation of experience business is the whole mystery anyway IMHO. Cheers, Günther -- Günther Greindl Department of Philosophy of Science University of Vienna [EMAIL PROTECTED] http://www.univie.ac.at/Wissenschaftstheorie/ Blog: http://dao.complexitystudies.org/ Site: http://www.complexitystudies.org --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Boltzmann brains
On Sat, Jul 07, 2007 at 07:56:57AM -0700, LauLuna wrote: > > I have never been able to understand how a singularity can be highly > ordered. Is there any room for order in such a tiny thing? > > Best Highly ordered means small entropy. All you need is a small number of states, so small things naturally have small entropy, and large things naturally have high entropy. What's unnatural are large things with low entropy. Cheers -- A/Prof Russell Standish Phone 0425 253119 (mobile) Mathematics UNSW SYDNEY 2052 [EMAIL PROTECTED] Australiahttp://www.hpcoders.com.au --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Boltzmann brains
I have never been able to understand how a singularity can be highly ordered. Is there any room for order in such a tiny thing? Best On May 31, 1:51 pm, Russell Standish <[EMAIL PROTECTED]> wrote: > I came across a reference to Boltzmann brains in a recent issue of New > Scientist. The piece, quoted in full is: > > Spikes in space-time > > There is another way to think about why our universe began in a highly > ordered or "low entropy" state. In 2002, a group of physicists led by > Leonard Susskind at Stanford University in California proposed that > entities capable of observing the universe could arise via random > thermal fluctuations, as opposed to the big bang, galaxy formation and > evolution. This idea has been explored by others, including Don Page > at the University of Alberta in Edmonton, Canada. Some researchers > argue that under certain conditions, self-aware entities in the form > of disembodied spikes in space-time - "Boltzmann brains" - are more > likely to emerge than complex life forms. Because they depend on > fluctuations of particles, Boltzmann brains would be more common in > regions of high entropy than low entropy. If the universe had started > out in a state of high entropy, it would be more likely to be > populated by Boltzmann brains than life forms like us, which suggests > that the entropy of our early universe had to be low. As a low-entropy > initial state is unlikely, though, this also implies that there are a > huge number of other universes out there that are unsuitable for us. > > It seemed to me that a Boltzmann brain was none other than one of our > white rabbits, or at least very closely related. Any thoughts? > > -- > > - > A/Prof Russell Standish Phone 0425 253119 (mobile) > Mathematics > UNSW SYDNEY 2052 [EMAIL PROTECTED] > Australiahttp://www.hpcoders.com.au > - --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Boltzmann brains
On 02/06/07, "Hal Finney" <[EMAIL PROTECTED]> wrote: > Another possibility is that Boltzmann Brains arising out of chaos are the > > observer moments which associate to produce the first person appearance > of > > continuity of consciousness and an orderly universe. Binding together > > observer moments thus generated is no more difficult than binding > together > > observer moments generated in other multiverse theories. > > So how would this explain why we see an orderly universe? I think we > would have to say that Boltzmann brains that remember an orderly universe > are substantially smaller (take up fewer Planck units) than those that > remember chaotic ones. > > I considered this possibility but I couldn't come up with a good > justification. Now, keep in mind that the Boltzmann brain does not have > to literally be a brain, with lobes and neurotransmitters and blood; > it could be any equivalent computational system. Chances are that true > "Boltzmann brains" would be small solid-state computers that happen to > hold programs that are conscious. Shrinking the brain even a little > increases its probability of existence tremendously. My immediate thought on hearing the term was that the Boltzmann Brains are due to fortuitous arrangement of matter in any physical system, such as interstellar clouds of hydrogen, which happens to instantiate a particular Turing machine, but only for a tiny instant before it goes into another arrangement. Thus, not only will smaller systems be more frequent, but briefer systems will be more frequent; it is very unlikely that a large and long-lasting entity like a human brain will appear by chance, but rather more likely that very brief human brain-equivalent snapshots will arise, widely separated in time and space. This is really very much like saying "every possible observer moment exists", and then trying to define a probability or measure which explains why in fact we tend to experience a certain kind of observer moment. (I am assuming that probability makes sense even though we are speaking of > events that happen a countably infinite number of times; both Boltzmann > brains and whole universes like ours will appear infinitely often in > the de Sitter state, but the smaller systems will be far more frequent. > I assume that this means that we would be more likely to experience > being the small systems then the big ones, even though both happen an > infinite number of times.) > > So to explain the lawfulness we would have to argue that Boltzmann brains > that remember lawful universes can be designed to be smaller than those > that remember chaotic universes, as well as slightly lawless flying-rabbit > universes. It's not completely implausible that the greater simplicity > of a lawful universe would allow the memory store of the Boltzmann > brain to be made smaller, as it would allow clever coding techniques to > compress the data. However one would think that memories of universes > even simpler than our own would then be that much more likely, as would > memories of shorter lifetimes and other possibilities to simplify and > shrink the device. This explanation doesn't really seem to work. > -- Stathis Papaioannou --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Boltzmann brains
A criticism to the whole idea. We actually do not have a definition of observer. We don't know what structure is needed for consciousness and even what phenomenon is the basic cause of a mental entity. In such an atmosphere one can oppose in the same (somehow in-scientific) way; for example I say: Is there any point in time where you can say some substances constitute a conscious being before that and unconscious one after it? If we're relying on physicism in philosophy of mind(and the whole BB idea, seems to have that implicit assumption), then such line is meaningless, because we know that it(existence of such line) is not true for us as conscious observers and if there's no such line... you know what happens. On 5/31/07, Russell Standish <[EMAIL PROTECTED]> wrote: > > > I came across a reference to Boltzmann brains in a recent issue of New > Scientist. The piece, quoted in full is: > > > Spikes in space-time > > There is another way to think about why our universe began in a highly > ordered or "low entropy" state. In 2002, a group of physicists led by > Leonard Susskind at Stanford University in California proposed that > entities capable of observing the universe could arise via random > thermal fluctuations, as opposed to the big bang, galaxy formation and > evolution. This idea has been explored by others, including Don Page > at the University of Alberta in Edmonton, Canada. Some researchers > argue that under certain conditions, self-aware entities in the form > of disembodied spikes in space-time - "Boltzmann brains" - are more > likely to emerge than complex life forms. Because they depend on > fluctuations of particles, Boltzmann brains would be more common in > regions of high entropy than low entropy. If the universe had started > out in a state of high entropy, it would be more likely to be > populated by Boltzmann brains than life forms like us, which suggests > that the entropy of our early universe had to be low. As a low-entropy > initial state is unlikely, though, this also implies that there are a > huge number of other universes out there that are unsuitable for us. > > > It seemed to me that a Boltzmann brain was none other than one of our > white rabbits, or at least very closely related. Any thoughts? > > -- > > > > A/Prof Russell Standish Phone 0425 253119 (mobile) > Mathematics > UNSW SYDNEY 2052 [EMAIL PROTECTED] > Australiahttp://www.hpcoders.com.au > > > > > > -- Mohsen Ravanbakhsh, --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Boltzmann brains
Stathis Papaioannou <[EMAIL PROTECTED]> writes: > On 01/06/07, "Hal Finney" <[EMAIL PROTECTED]> wrote: > > The reference to Susskind is a paper we discussed here back > > in Aug 2002, Disturbing Implications of a Cosmological Constant, > > http://arxiv.org/abs/hep-th/0208013 . The authors argued that in current > > cosmological models the universe dies a heat death and falls into a steady > > state of exponential expansion which goes on forever. In that state, > > quantum gravity fluctuations will eventually cause macroscopic objects > > to appear. This is extremely rare but still with infinite time to work > > with, every object will appear an infinite number of times. That includes > > disembodied brains, the so-called Boltzmann brains, as well as planets and > > whole universes. But the smaller objects are vastly more common, hence it > > is most likely that our experiences are due to us being a Boltzmann brain. > > It isn't generally the case that given a non-zero probability of an event E > occurring per trial (or per unit time period), then as the number of trials > n approaches infinity the probability of E occurring approaches 1. For > example, if Pr(E) = 1/2^n, then even though Pr(E) is always non-zero, the > probability of ~E as n->inf is given by the infinite product of (1-1/2^n), > which converges to approximately 0.288788, not zero. So if the exponential > expansion is associated with a continuous decrease in the probability that > an event of interest will occur during a unit time period, that event may > still never occur given infinite time, even though at no point can the event > be said to be impossible. Right, but apparently the physics doesn't work this way. The papers just seem to take the size of the necessary object in Planck units and say the probability of it popping into existence is 1/e^size. This is constant and therefore it will happen an infinite number of times. > > This has a few bad implications; one is that our perceptions should end > > and not continue (but they do continue) and another is that brains would > > be just as likely to (falsely) remember chaotic universes as lawful ones > > (but we only remember lawful ones). So this model is not considered > > consistent with our experiences. > > Another possibility is that Boltzmann Brains arising out of chaos are the > observer moments which associate to produce the first person appearance of > continuity of consciousness and an orderly universe. Binding together > observer moments thus generated is no more difficult than binding together > observer moments generated in other multiverse theories. So how would this explain why we see an orderly universe? I think we would have to say that Boltzmann brains that remember an orderly universe are substantially smaller (take up fewer Planck units) than those that remember chaotic ones. I considered this possibility but I couldn't come up with a good justification. Now, keep in mind that the Boltzmann brain does not have to literally be a brain, with lobes and neurotransmitters and blood; it could be any equivalent computational system. Chances are that true "Boltzmann brains" would be small solid-state computers that happen to hold programs that are conscious. Shrinking the brain even a little increases its probability of existence tremendously. (I am assuming that probability makes sense even though we are speaking of events that happen a countably infinite number of times; both Boltzmann brains and whole universes like ours will appear infinitely often in the de Sitter state, but the smaller systems will be far more frequent. I assume that this means that we would be more likely to experience being the small systems then the big ones, even though both happen an infinite number of times.) So to explain the lawfulness we would have to argue that Boltzmann brains that remember lawful universes can be designed to be smaller than those that remember chaotic universes, as well as slightly lawless flying-rabbit universes. It's not completely implausible that the greater simplicity of a lawful universe would allow the memory store of the Boltzmann brain to be made smaller, as it would allow clever coding techniques to compress the data. However one would think that memories of universes even simpler than our own would then be that much more likely, as would memories of shorter lifetimes and other possibilities to simplify and shrink the device. This explanation doesn't really seem to work. Hal --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Boltzmann brains
On 01/06/07, "Hal Finney" <[EMAIL PROTECTED]> wrote: The reference to Susskind is a paper we discussed here back > in Aug 2002, Disturbing Implications of a Cosmological Constant, > http://arxiv.org/abs/hep-th/0208013 . The authors argued that in current > cosmological models the universe dies a heat death and falls into a steady > state of exponential expansion which goes on forever. In that state, > quantum gravity fluctuations will eventually cause macroscopic objects > to appear. This is extremely rare but still with infinite time to work > with, every object will appear an infinite number of times. That includes > disembodied brains, the so-called Boltzmann brains, as well as planets and > whole universes. But the smaller objects are vastly more common, hence it > is most likely that our experiences are due to us being a Boltzmann brain. It isn't generally the case that given a non-zero probability of an event E occurring per trial (or per unit time period), then as the number of trials n approaches infinity the probability of E occurring approaches 1. For example, if Pr(E) = 1/2^n, then even though Pr(E) is always non-zero, the probability of ~E as n->inf is given by the infinite product of (1-1/2^n), which converges to approximately 0.288788, not zero. So if the exponential expansion is associated with a continuous decrease in the probability that an event of interest will occur during a unit time period, that event may still never occur given infinite time, even though at no point can the event be said to be impossible. This has a few bad implications; one is that our perceptions should end > and not continue (but they do continue) and another is that brains would > be just as likely to (falsely) remember chaotic universes as lawful ones > (but we only remember lawful ones). So this model is not considered > consistent with our experiences. > > > Because they depend on > > fluctuations of particles, Boltzmann brains would be more common in > > regions of high entropy than low entropy. If the universe had started > > out in a state of high entropy, it would be more likely to be > > populated by Boltzmann brains than life forms like us, which suggests > > that the entropy of our early universe had to be low. As a low-entropy > > initial state is unlikely, though, this also implies that there are a > > huge number of other universes out there that are unsuitable for us. > > I don't think this reasoning makes sense, for two reasons. First, even > though the universe did apparently start out in a low-entropy state, > hence giving an opportunity for non-Boltzmann (ie not disembodied) > brains like ours to form, still as argued above eventually it gets into > a high-entropy state and you then still have the problem of an infinite > number of Boltzmann brains. The choice then is between a universe that > starts high-entropy and has only Boltzmann brains, and one that starts > low-entropy and has a finite number of "normal" brains and an infinite > number of Boltzmann brains. It's not clear that the latter choice really > explains and justifies why we are non-Boltzmann. > > Second, even if so, as it says these ideas are usually applied in the > context of multiverse theories, so there would be an infinite number of > universes, some starting in low entropy and some in high entropy states. > Again we would have an infinite number of Boltzmann brains in the > multiverse compared with only a finite number of non-Boltzmann brains, > so we haven't really explained why we find ourselves in one of the > universes which has normal non-Boltzmann brains. > > I would suggest two ways out of the dilemma. The first is from physics. > One of the things I learned in my reading last night is that this > model of an infinite expanding universe may not actually work. This > so-called de Sitter state does not have a consistent quantum explanation. > The theory suggests that the de Sitter state may be inherently unstable > and will somehow decay, perhaps by tunnelling into another vacuum state. > This could happen fast enough that the total expected number of Boltzmann > brains is finite, potentially resolving the paradox. > > The other is from our measure-based reasoning. For various reasons we > might argue that the measure of brains existing in the extremely far > future is less than that of brains existing today. Such brains are much > smaller spatially in comparison to the universe as a whole than our brains > are today, for one thing, so perhaps they deserve a lesser share of the > universe's total measure. Also, the amount of information to specify > the location of such a brain in terms of Planck moments since the Big > Bang would be vastly greate
Re: Boltzmann brains
Russell Standish <[EMAIL PROTECTED]> writes: > I came across a reference to Boltzmann brains in a recent issue of New > Scientist. Coincidentally (or not) I was reading all about this last night, from the fqxi.org web site Max Tegmark mentioned a few weeks ago. The new blog entry by Anthony Aguirre discusses this issue and some related ones regarding multiverses, the Doomsday paradox, etc. I ended up reading several papers by Don Page and others. > The piece, quoted in full is: > > Spikes in space-time > > There is another way to think about why our universe began in a highly > ordered or "low entropy" state. In 2002, a group of physicists led by > Leonard Susskind at Stanford University in California proposed that > entities capable of observing the universe could arise via random > thermal fluctuations, as opposed to the big bang, galaxy formation and > evolution. This idea has been explored by others, including Don Page > at the University of Alberta in Edmonton, Canada. Some researchers > argue that under certain conditions, self-aware entities in the form > of disembodied spikes in space-time - "Boltzmann brains" - are more > likely to emerge than complex life forms. The reference to Susskind is a paper we discussed here back in Aug 2002, Disturbing Implications of a Cosmological Constant, http://arxiv.org/abs/hep-th/0208013 . The authors argued that in current cosmological models the universe dies a heat death and falls into a steady state of exponential expansion which goes on forever. In that state, quantum gravity fluctuations will eventually cause macroscopic objects to appear. This is extremely rare but still with infinite time to work with, every object will appear an infinite number of times. That includes disembodied brains, the so-called Boltzmann brains, as well as planets and whole universes. But the smaller objects are vastly more common, hence it is most likely that our experiences are due to us being a Boltzmann brain. This has a few bad implications; one is that our perceptions should end and not continue (but they do continue) and another is that brains would be just as likely to (falsely) remember chaotic universes as lawful ones (but we only remember lawful ones). So this model is not considered consistent with our experiences. > Because they depend on > fluctuations of particles, Boltzmann brains would be more common in > regions of high entropy than low entropy. If the universe had started > out in a state of high entropy, it would be more likely to be > populated by Boltzmann brains than life forms like us, which suggests > that the entropy of our early universe had to be low. As a low-entropy > initial state is unlikely, though, this also implies that there are a > huge number of other universes out there that are unsuitable for us. I don't think this reasoning makes sense, for two reasons. First, even though the universe did apparently start out in a low-entropy state, hence giving an opportunity for non-Boltzmann (ie not disembodied) brains like ours to form, still as argued above eventually it gets into a high-entropy state and you then still have the problem of an infinite number of Boltzmann brains. The choice then is between a universe that starts high-entropy and has only Boltzmann brains, and one that starts low-entropy and has a finite number of "normal" brains and an infinite number of Boltzmann brains. It's not clear that the latter choice really explains and justifies why we are non-Boltzmann. Second, even if so, as it says these ideas are usually applied in the context of multiverse theories, so there would be an infinite number of universes, some starting in low entropy and some in high entropy states. Again we would have an infinite number of Boltzmann brains in the multiverse compared with only a finite number of non-Boltzmann brains, so we haven't really explained why we find ourselves in one of the universes which has normal non-Boltzmann brains. I would suggest two ways out of the dilemma. The first is from physics. One of the things I learned in my reading last night is that this model of an infinite expanding universe may not actually work. This so-called de Sitter state does not have a consistent quantum explanation. The theory suggests that the de Sitter state may be inherently unstable and will somehow decay, perhaps by tunnelling into another vacuum state. This could happen fast enough that the total expected number of Boltzmann brains is finite, potentially resolving the paradox. The other is from our measure-based reasoning. For various reasons we might argue that the measure of brains existing in the extremely far future is less than that of brains existing today. Such brains are much smaller spatially in comparison to the universe as a whole than our brains are today, for one thing, so perhaps they deser
Boltzmann brains
I came across a reference to Boltzmann brains in a recent issue of New Scientist. The piece, quoted in full is: Spikes in space-time There is another way to think about why our universe began in a highly ordered or "low entropy" state. In 2002, a group of physicists led by Leonard Susskind at Stanford University in California proposed that entities capable of observing the universe could arise via random thermal fluctuations, as opposed to the big bang, galaxy formation and evolution. This idea has been explored by others, including Don Page at the University of Alberta in Edmonton, Canada. Some researchers argue that under certain conditions, self-aware entities in the form of disembodied spikes in space-time - "Boltzmann brains" - are more likely to emerge than complex life forms. Because they depend on fluctuations of particles, Boltzmann brains would be more common in regions of high entropy than low entropy. If the universe had started out in a state of high entropy, it would be more likely to be populated by Boltzmann brains than life forms like us, which suggests that the entropy of our early universe had to be low. As a low-entropy initial state is unlikely, though, this also implies that there are a huge number of other universes out there that are unsuitable for us. It seemed to me that a Boltzmann brain was none other than one of our white rabbits, or at least very closely related. Any thoughts? -- A/Prof Russell Standish Phone 0425 253119 (mobile) Mathematics UNSW SYDNEY 2052 [EMAIL PROTECTED] Australiahttp://www.hpcoders.com.au --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
