RE: Is the universe computable
Why is it assumed that a multiple "runs" makes any difference to the measure? If the computation is reversible we could run the simulation backwards - even though the initial state make seem contrived because it leads to a low entropy at the end of the computation. Given that the simulated beings don't know the difference (their subjective time runs in the direction of increasing entropy) the fact that the simulation is done in reverse is irrelevant to them. Would a simulation done in reverse contribute to the measure? Once we say that all possible computations exist in the Platonic sense, it seems to me that running them is irrelevant. Of course it is agreed that the existence hypothesis tells us nothing about their relative measure. Does anyone have some principles to go by? I presume a theory of measure along the lines described by Jesse would need to account for the measure of mappings between computations. Presumably a simple correspondence would have higher weighting than some complicated mapping between two computations. - David > -Original Message- > From: Jesse Mazer [mailto:[EMAIL PROTECTED] > Sent: Saturday, 17 January 2004 4:56 AM > To: [EMAIL PROTECTED] > Subject: Re: Is the universe computable > > Eugen Leitl: > >I have trouble alternating between the internal and the external observer > >view. So we have a machine crunching bits, sequentially falling from > state > >to > >state. This spans a continous trajectory. We can make a full record of > that > >trajectory, eliminating a time axis. When does the subjective observation > >of > >existence assemble into place? The first time the computation was made? > > > >I have trouble seeing my subjective observer experience as a sequence of > >frames, already computed. Is the first run magical, and the static record > >dead meat? I'm confused. > > I think the most common theory on this list is that there is nothing > special > about the first vs. the second run--rather, the total number of runs helps > determine the measure of that subjective experience. If I scan my brain > into > a computer knowing that my first experience after being uploaded will > depend > on what environment is created for my simulated brain, I should make sure > my > friends do lots of runs where the upload wakes up in an idyllic > environment > and that my enemies don't get their hands on the program and do a lot of > runs where the upload is used as a slave or something. If my enemies do > manage to get a copy and do a few of those runs before they are caught and > stopped by the Society for the Prevention of Cruelty to Uploads, my > friends > can at least try to minimize the damage by doing so many runs of the > idyllic > environment that the probability of having that experience after I wake up > will be much greater than the probability that my first experience after > being uploaded will be waking up as a slave to my enemies (according to > this > particular theory of how measure works, anyway). > > Jesse Mazer > > _ > Get a FREE online virus check for your PC here, from McAfee. > http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
Fw: The Facts of Life and Hard AI
> The "Emergence of Life" paper is talking specifically about those sorts
> of life that can emerge
> WITHOUT THE ASSISTANCE OF AN ALREADY SMARTER, MORE-ORGANIZED AGENT.
> That's why that kind of life ("natural" life) is a truly emergent or
> (emergent from less-order) system.
>
Well, I'm an agnostic, but your point is well taken here. That said who was
that talking about a "god program", Hal?
> One way of looking at A.I. is that it may become in some attributes
> life-like (I prefer just to say
> it will become a true cognitive agent i.e. a true thinker (active
> modeler) without NECESSARILY
> also independently being a fully self-sufficient life-form. If WE can be
> considered part of the environment
> of AIs, then they are a life-form that uses US to reproduce (at least
> initially).
>
Paraticism and symbiotic raltioanships are common amoung "natual" life
forms.
> It's traditional to think of the environment of a lifeform as less
> ordered than the lifeform itself, so this
> AI case, where the environment includes extremely ordered self-emergent
> SAS's (ourselves)
> is a little bit strange situation and it's hard to categorize.
>
Well, speaking of symbiosis, is my gut less "ordered" than the critters like
ecoli that make a home there? I'm not sure I buy that generalization. I'm
more of the Starr hierarchal ecology ilk (by way of Koestler) or perhaps
Joslyn's meta-transition model; adaption is as much about feedback between
hiearchal scales as within them...
> With AI, it's probably best just to say that there is another emergent
> system emerging, which is
> (at this stage) a combination of humans (the human-species pattern and
> its behaviours) and the software
> (informational) and computing hardware technological/cultural artifacts
> we produce, acting together
> to form the new emergent system.
>
No issues with this view; I wouldn't be at all surprised if cyborgs inherit
the earth.
> People do talk about AI computers/robots and nano-tech, in combination
> perhaps, becoming self-sufficient
> (self-replicating and self-advancing/adapting independent of their human
> creators.)
>
> I have no trouble believing that this is in-principle possible. I just
> want to point out that
> the properties for true long-term sustainability of pattern-order are
> HARD (difficult, onerous)
> requirements, not easy ones. Natural life (in the admittedly single case
> we know) is highly constrained
> because of the constraints on its long-term survival and incremental
> improvement in a less-ordered
> environment.
>
"Hard" may not be the most useful term here; highly constrained, yes; Once
the conditions were sufficient, I think the rest was inevitable. Here I have
to play the "nano-tech" card; one can imagine some uber termite mound
encompassing the globe (and beyond) custom designed (grown?) from the atomic
scale up to our progeny's specs;
The prototype of just such an ecology may well already be in place (were
leveraging it now); with evermore bandwidth, interconnectivity, agency and
now the advent of "grid" distributed computation it's conceivable that
"something" is already in gestation. But I haven't a clue about that..
> It seems easier (but is it much easier really?) to get AIs to
> self-improve/self-sustain purely as virtual (informational) patterns
> or entities (i.e. as software and data ie. pure-informational
> entities/thinkers/knowledge-bases) rather than as informational/physical
> hybrids as we are. I suppose some of the people on the everything-list,
> myself included, may see the
> distinction between informational and physical as more just a matter of
> degree than of substance,
> so this is a puzzling area. Certainly both human-built computers and
> physical machines (robots eg mars rovers,
> nanobots etc) have a long way to go, not only in their basic FUNCTIONAL
> development, but
> perhaps more significantly and certainly more difficultly in their
> ROBUSTNESS (lack of brittleness)
> AND EVOLVABILITY (& META-EVOLVABILITY?) criteria, and their raw-material
> choice
> (natural life uses primarily the most commonly occurring-in-the-universe
> chemically-bondable elements
> (hydrogen, carbon, oxygen, nitrogen etc) for good reason), before they
> could hope to be very self-sustainable.
>
Lanier's "phenotropics" speaks to that brittleness factor. The promise and
the danger may both lay in unleashing genetic programming type strategies on
the problem; "evolving" our broods towards those goals of robustness and
self sustainability w/o really having a handle on the process. Might be
prudent to review Asimov!
> It is interesting to speculate that the mechanisms available to a future
> AI robot/nanotech-conglomerate/web-dweller
> for self-adaptation might be far more flexible and wide-ranging than
> those available to early natural life on Earth,
> because we are building AI's partly in our image, and
> we, after all, by becoming general thinker/planners (information
> maestros if you will)
Re: Determinism - Mind and Brain
> Plato is Plato. Can't argue with that logic. (Although perhaps Korzybski might...) ;) > And the last thing I want to condone is a special kind of 'modernization': > to fashion the human complexity (mind?) after the (designed) functions of a > machine, which is a partial product of the human mind. - AI is still "A". > Would a artificial self-aware entity emerging from human technology represent "mind"? Who can tell. But it may not be a meaningful question. Such a system that might unerringly pass the turing test would probably be assumed to be thinking and engaged accordingly. Just as I believe I think but and can only assume that others do based on their behavior communications. Skinner was not wrong, just woefully incomplete. Obviously this debate won't be settled to everyone's (anyone's?) satisfaction here. It may well be settled, though, to all but the most committed skeptics in the lifetime of some of those on this list, if not in my own. If so, we most likely will never be sure of the entitys' "consciousness". And they would just as likely have to take our word about it regarding ours (our "intelligence" may be even less obvious to them). Cheers CMR
Re: Determinism - Mind and Brain
My 2½ pence on "Mind AND Brain":
IMO (no persuasion intended) our mental complexity is an ASPECT of the
complexity human (which is part(ner) of enveloping (interinfluencing?)
complexities unlimited - applies a material tool with a very high level (how
high is it?) of interconnectional complexity. It is called the (neuronal?)
brain. The entire aspect of mentality is what I call mind, together with
that material tool. I do refrain from (hypothetical) hierarchical
ordinations. The components(?) act in some concert, the mechanism(?) of
which may be getting discovered sometimes in the future. Our 'body' is not
restricted to the "not the brain" parts, our neuronal bio-functions are
bodyfunctions allright, contributing to the inseparable process of the
(inseparable) complexity. To separate some imaginary components from a
complexity seems to me just futile. I talk about neuron-firings, toe- or
toothaches, love and hunger, all pertinent to the management of the human
beiing ("body and brain").
I think we can get past the unsurmountable problem whether 'neurons think?'
Even in thinking physics: the transition from physical data into mental
quality, the description of a 'living' (imperfect, unreliable, forgetful)
memory vs the perfect machine-storage, the diversity of reflections upon
"the same" input, etc. Lenin
said that quantity turns into quality - but that was a different aspect.
The still highest authorities in this question worked within the cognitive
nventory of 2500 years ago and the later thinkers don't dare to modernize.
Plato is Plato.
And the last thing I want to condone is a special kind of 'modernization':
to fashion the human complexity (mind?) after the (designed) functions of a
machine, which is a partial product of the human mind. - AI is still "A".
John Mikes
Scientific Agnosticist
Original Message -
From: "Eric Hawthorne" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Saturday, January 17, 2004 9:59 PM
Subject: Re: Determinism
Re: The Facts of Life and Hard AI
CMR wrote:
I think it's useful here to note that from the "strong" AI point of view
"life as it could be" is empahasized as opposed to "life as we know it".
It's also worth pointing out that the latter is based upon a single data
point sample of all possible life, that sample consisting of life that
(apparently) evolved on our planet. Given that, defining life in the
universe, and certainly in all universes, based only upon that sample is
speculative at best. (Unless, as some claim, our biosphere is truly unique;
I doubt this is the case).
Just to be clear I'm not at all attempting to "dis" the possibilities of
"hard" artificial intelligence.
I studied it to postgrad-level in the past, and would hope to be able to
work in that field for real some
day.
The "Emergence of Life" paper is talking specifically about those sorts
of life that can emerge
WITHOUT THE ASSISTANCE OF AN ALREADY SMARTER, MORE-ORGANIZED AGENT.
That's why that kind of life ("natural" life) is a truly emergent or
(emergent from less-order) system.
One way of looking at A.I. is that it may become in some attributes
life-like (I prefer just to say
it will become a true cognitive agent i.e. a true thinker (active
modeler) without NECESSARILY
also independently being a fully self-sufficient life-form. If WE can be
considered part of the environment
of AIs, then they are a life-form that uses US to reproduce (at least
initially).
It's traditional to think of the environment of a lifeform as less
ordered than the lifeform itself, so this
AI case, where the environment includes extremely ordered self-emergent
SAS's (ourselves)
is a little bit strange situation and it's hard to categorize.
With AI, it's probably best just to say that there is another emergent
system emerging, which is
(at this stage) a combination of humans (the human-species pattern and
its behaviours) and the software
(informational) and computing hardware technological/cultural artifacts
we produce, acting together
to form the new emergent system.
People do talk about AI computers/robots and nano-tech, in combination
perhaps, becoming self-sufficient
(self-replicating and self-advancing/adapting independent of their human
creators.)
I have no trouble believing that this is in-principle possible. I just
want to point out that
the properties for true long-term sustainability of pattern-order are
HARD (difficult, onerous)
requirements, not easy ones. Natural life (in the admittedly single case
we know) is highly constrained
because of the constraints on its long-term survival and incremental
improvement in a less-ordered
environment.
It seems easier (but is it much easier really?) to get AIs to
self-improve/self-sustain purely as virtual (informational) patterns
or entities (i.e. as software and data ie. pure-informational
entities/thinkers/knowledge-bases) rather than as informational/physical
hybrids as we are. I suppose some of the people on the everything-list,
myself included, may see the
distinction between informational and physical as more just a matter of
degree than of substance,
so this is a puzzling area. Certainly both human-built computers and
physical machines (robots eg mars rovers,
nanobots etc) have a long way to go, not only in their basic FUNCTIONAL
development, but
perhaps more significantly and certainly more difficultly in their
ROBUSTNESS (lack of brittleness)
AND EVOLVABILITY (& META-EVOLVABILITY?) criteria, and their raw-material
choice
(natural life uses primarily the most commonly occurring-in-the-universe
chemically-bondable elements
(hydrogen, carbon, oxygen, nitrogen etc) for good reason), before they
could hope to be very self-sustainable.
It is interesting to speculate that the mechanisms available to a future
AI robot/nanotech-conglomerate/web-dweller
for self-adaptation might be far more flexible and wide-ranging than
those available to early natural life on Earth,
because we are building AI's partly in our image, and
we, after all, by becoming general thinker/planners (information
maestros if you will) have managed
to increase enormously the range of ways we can adapt the environment to
our needs. (Caveat: As an eco-aware
person however I can tell you the jury's out on whether we're doing this
to system-survival-levels of sophistication,
and the jury's leaning toward "guilty" of eco-cide - or more precisely
guilty of severe eco-impoverishment and disordering).
BTW I'm most excited today in the AI field by the possibilities that the
combination of the WWWeb's
information as accessed via google (and similar) and AI
insights/technologies will have. The web is
not a big distributed brain yet, but it could get there.
Eric
Re: The Facts of Life
> Just to be mischievous, I'll here pronounce "the facts of life" or more > precisely > "a sketch of a theory of the emergence of life" which will serve the > purpose of partially constraining/ > defining what is meant by life. This is a hobby project. Wow! A Rather exhaustive and admittedly impressive sketch, that. I'll concede that given those requirements, "life" may indeed be rare in this and other universes. I think it's useful here to note that from the "strong" AI point of view "life as it could be" is empahasized as opposed to "life as we know it". It's also worth pointing out that the latter is based upon a single data point sample of all possible life, that sample consisting of life that (apparently) evolved on our planet. Given that, defining life in the universe, and certainly in all universes, based only upon that sample is speculative at best. (Unless, as some claim, our biosphere is truly unique; I doubt this is the case). Here, I think that I tend to agree with Kory that patterns in a simulation need only meet some set of basic recognized criteria (perhaps Dawkins replicators?) within the contraints of the self consistent "physics" of the "simulation" in order to be considered life. Ilachkinski suggests that as AI extends the exploration of possible life, the associated self-consistent artificial physics might well point to "physics as it could be" as opposed to the physics we know(?). CMR
Re: The Facts of Life
Eric, I love your 'project'. Do not despair by my liking it, it does make sense to me even outside of the orthodox physicalistic thinking. I don't copy the long text, everybody got it, only some little parts of it, to which I paste some comments (marked - [JM]:) John Mikes - Original Message - From: "Eric Hawthorne" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, January 18, 2004 3:27 AM Subject: The Facts of Life > > CMR wrote: > > >Indeed. The constraints to, and requirements for, terrestrial life have had > >to be revised and extended of late, given thermophiles and the like. Though > >they obviously share our dimensional requisites, they do serve to highlight > >the risk of prematurely pronouncing the "facts of life". > > > Just to be mischievous, I'll here pronounce "the facts of life" or more > precisely "a sketch of a theory of the emergence of life" which will serve the > purpose of partially constraining/defining what is meant by life. This is a > hobby project. > > The Emergence of Life Via Weak (Stochastic) Physical Pattern Replication == > Definitions: > > "pattern" a form of order or regularity, which can be described by a > finite and usually simple set of constraints.(...) [JM]: I'd add: ...,a 'model', chosen from a finite set of observed cases. SNIP... > Abstract: > - > The natural selection process that results in the evolution of lifeforms > as we know them can be extended > backwards in time further than is traditionally assumed, to fully > explain the emergence of life from chance-occurring patterns of >matter and energy ... that lifeforms exhibit. ([JM]: I know: on this list of physicists one can not escape from the word 'energy'. Could anybody DEFINE its meaning - not identifying what it does or how it compares to other concepts (measurements) or why we have to think of it, just the term, in a classically identified meaning) SNIP > Characteristics of a living organism: > --- > 1. It self-replicates (aka reproduces). [JM]: since the prokaryotes nothing reproduces. Nothing replicates 'self'. Especially since the invention of sexes: two organisms activate a process in which a third one is produced as a result, not matching either of the instigating parents. It is the 'species' that may said to reproduce, even this only superficially meant, because the ever changing environmental circumstances result in variations (mutations?) of the reaction-product. The variant can be applicable to the (changed, new) environment, or not, when it does not proliferate. The first case - as observed after some time (many generations, in science) are called "adaptation and natural selection". The 'bad' product died out and are not even observed. (Concurring ideas in Appendix B). SNIP > 3. It is an autonomous agent (within some environmental constraints.) [JM]: perfect with the parenthesis, viewed WITHIN the set boundaries of our modelled observation. (Similarly expressed further on). SNIP > Thesis ... [JM]: I might have (similar?) ideas - expressed in a less physiclistic mode, which, by some, may sound 'just less precise'. Exactly, since I think in not-so-restricted boundary-enclosed modelling and so the equations of identical values are more fuzzy (influenced by the 'neglected' data outside the circle of the actual observational model). This was also an 'unprecise' statement. I concur with the par (in a sense that 'environment is beyond boundaries): > Definition-weakening 3: ENVIRONMENT-DRIVEN METABOLISM< extended to more than just metabolism. The Appendices require more time to my readings. Appendix A is formulated in a rather 'physicalistic' language.A short remark concerning App. B is included above. So I skip the rest. I thank Eric for a great idea and its excellent exposition. [JM] > SNIP
Re: Computational complexity of "running" the multiverse
To below and many others on the list: Do we really assume the MWI or any setup of the (poorly identified) existence we dream up for the unlimited system of "universes galore" in our little 'material-inhibited' minds, as being totally 'constructed' according to OUR recent explanations of OUR poorly understood observations on THIS little muddy planet during the past split second of its churnings? John Mikes - Original Message - From: "scerir" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, January 18, 2004 5:07 AM Subject: Re: Computational complexity of "running" the multiverse > From: "Eric Hawthorne" > > > One of the issues is the computational complexity of "running all the > > possible i.e. definable programs" to create an informational multiverse > > out of which consistent, metric, regular, observable info-universes > > emerge. If computation takes energy (as it undeniably does WITHIN our > > universe), then an unfathomably impossibly large amount of > > "extra-universal" energy would be required to compute all > > info-universes. > > Tree points here, or, maybe, three non-senses (in this case > I apolozige). A) Is there a principle of conservation of energy > in MWI? I do not think so. Does it mean that - in principle - > you could have a world in which there is "omnipotence" or > a very large amount of energy? B) Which is the role of > observers in that "info-universal-computation"? Do they > cooperate? Is such a computation a "participatory" computation > (in the sense of Wheeler)? Possibility of delayed choices, > anthropic "functionals", Banah-Tarski weirdness, and other > amenities ... like http://www.arxiv.org/abs/quant-ph/0109022 > C) According to Spreng the parameters are three: energy, time, > existing information. Thus you can minimize energy by using > more time and more information. > s.
Re: Tegmark is too "physics-centric"
On Sat, Jan 17, 2004 at 11:05:18PM -0800, Hal Finney wrote: > Yes, I see that that is true. I think it points to a problem with some > of the simple conceptualizations of measure, about which I will say > more below.But let me ask if you agree that considering Conway's 2D > Life world with simply-specified initial conditions as in your example, > that conscious life would be extraordinarily rare? Life is an universal CA (it is possible to implement Life in Life e.g.), but not all universal CAs are suitably structure to support emergence of life from a random pattern. Biggest problem is translation, Life doesn't support translation of large blocks, so you have to implement storage/copy, it doesn't have noniteractive particles natively, it doesn't conserve noise naturally (you get increasingly rare splotches of noise of gliders colliding with stationary/evolving structures). You could implement a more suitable CA (or any other machine) in Life, but it couldn't emerge naturally (it would have a huge cell unit size), and it's not obvious it could eventually overgrow the entire substrate, once emerged (there might be tricks with perimeter guards, etc., but the whole point is that Life is pretty hostile to emergence of life. > I want to say, vastly more rare than in our universe, but of course we > don't know how rare life actually is in our universe, so that may be a It would be nice if we could find several independently emerged life nucleation points in our solar system (difficult, given the high rates of crosscontamination through impact ejecta). If we don't find them, the emergence of local life is of course causally linked to us, so it's still biased by the anthropic principle. We need other data points, maybe from nearby systems. > hard claim to justify. But the point is that our universe has stable > structures; it has atoms of dozens of different varieties, which can form > uncountable millions of stable molecules. It has mechanisms to generate > varieties of these different molecules and collect them together in > environments where they can react in interesting ways. We don't have a > full picture of how life and consciousness evolved, but looking around, > it doesn't seem like it should have been THAT hard, which is where the > Fermi paradox comes from. In many ways, our universe seems tailor made There's not much of a paradox, if you look at Fermi from anthropic principle angle. And we absolutely can't say how probable emergence of an advanced culture is (given the above). We have been leading unusually sheltered lifes, and there's nothing particularly obvious about us coming into being scant few 100 megayears before the curtain falls on life in the local environment. > for creating observers. > > In contrast, in the Life world there are no equivalents to atoms or > molecules, no chemical reactions. It's too chaotic; there's not enough Life's about patterns, not atoms or reactions. I agree that Life is sterile, however, and there are no obvious tweaks in how make it work better. However, most digital physics people seem to think the unit cell is at Planck scale, or below, and I have absolutely no idea how a Plack scale life would look like on macroscale, considering how much volume one has, and how many iterations occur there. I never figured out how to get rid of grid assymetries shining through to macroscale, and how to generate rule tables with conservation laws intact, but then there are perfectly spherical sound waves, and wave interferece in stupid lattice gas automata, of all things. That's pretty surprising, so perhaps it doesn't make sense to rule out too much yet. > structure. Replicators and life seem to require a balance between > chaos and stasis, and Life is far too dynamic. It just looks to me > like it would be almost impossible for replicators to arise naturally. > Almost impossible, but not absolutely impossible, so if you tried enough > initial conditions as you suggest, it would happen. I won't belabor > this argument unless you disagree about the ease with which life might > arise in a Life universe, and consciousness evolve. I'd rather amazed to see large assemblies capable of translation in Life universe, already. > that those are too parochial. But as I recall he had a number of broad > arguments that would apply even to a Life-like universe. > > This was the motivation for the idea I proposed a few days ago, that > for applying anthropic reasoning, a universe should get a "bonus" if > it had a high density of observers, rather than merely a high absolute I'm not sure how that follows, using anthropic principle and relativistic pioneer expansion wavefront (which directly follows from Darwin, and current knowledge of propulsion methods) the Fermi paradoxon completely disappears. > number of them. It's too easy to create universes with low-density > observers, as your example of Life suggests. But just as the existence > of a counting progr
Re: Tegmark is too "physics-centric"
At 1/17/04, Hal Finney wrote: But let me ask if you agree that considering Conway's 2D Life world with simply-specified initial conditions as in your example, that conscious life would be extraordinarily rare? I certainly agree that it would be "extraordinarily rare", in the sense that the size of the lattice would need to be very big, and the number of clock-ticks required would need to be very large. But "big" and "large" are such relative terms! Clearly, our own universe is very, very big. The question is, how can we sensibly determine whether life is more likely in our universe or in Conway's Life universe? I don't believe we have anywhere near enough data to answer this question, but I don't think it's unanswerable in principle. Fredkin actually believes that our universe is a 3+1D cellular automata, and if anyone ever found such a description of our physics (or some other fundamentally computational description), then we could directly compare it with Conway's Life, determining for each one how big the lattice needs to be, and how many clock-ticks are required, for life to appear with (say) 90% probability. (Of course, this determination might be difficult even when we know the rules of the CAs. But we can try.) One thing that you'd have to take into account is the complexity of the rules you're comparing, including the number of states allowed per cell. Not only are the rules to Conway's Life extremely simple, but the cells are binary. All things being equal, I would expect that an increase in the complexity of the rules and the number of cell-states allowed would decrease the necessary lattice-size and/or number of clock-ticks required for SASs to grow out of a pseudo-random initial state. I mention this to point out a problem with our intuitions about our universe vs. Conway's Life: the description of our universe is almost certainly more complex than the description of Conway's Life with a simple initial state. If Fredkin actually succeeds in finding a 3+1D CA which describes our universe, it will almost certainly require more than 2 cell-states, and its rules will certainly be more complex than those of the Life universe. We have to take this difference into account when trying to compare the two universes, but we have nowhere near enough data to quantify the difference currently. We really don't know what size of space in the Life universe is equivalent to (say) a solar system in this universe. In a way, this is all beside the point, since I have no problem believing that one CA can evolve SASs much more easily than some other CA whose rules and initial state are exactly as complex. (In fact, this must be true, since for any CA that supports life at all, there's an equally complex one that isn't even computation universal.) I have no problem believing that the Life universe is, in some objective sense, not very conducive to SASs. Perhaps it's less conducive to SASs than our own universe, although I'm not convinced. What I have a problem believing is that CAs as a class are somehow less conducive to observers than quantum-physical models as a class. In fact, I think it's substantially more likely that there are relatively simple CA models (and other computational models) that are much more conducive to SASs than either Conway's Life universe or our own. Models in which, for instance, neural-net structures arise much more naturally from the basic physics of the system than they do in our universe, or the Life universe. In many ways, our universe seems tailor made for creating observers. I understand this perspective, but for what it's worth, I'm profoundly out of sympathy with it. In my view, computation universality is the real key - life and consciousness are going to pop up in any universe that's computation universal, as long as the universe is big enough and/or it lasts long enough. (And there's always enough time and space in the Mathiverse!) When I think about the insane, teetering, jerry-rigged contraptions that we call life in this universe - when I think about the tortured complexity that matter has to twist itself into just to give us single-celled replicators - and when I think about the insane reaches of space we see around us (even if we end up finding life in practically every solar system, there's a crazy amount of space even between planets, not to mention stars) - I find it easy to believe that our universe is just one of those countless universes out there in Mathspace which isn't especially conducive to life at all, but is simply computation universal, so life pops up eventually. Because of the above conclusions, the problem of measure is a serious one for me. I don't have a clue why I would be more likely to find myself in a universe like this one instead of some CA universe. Regarding your suggestion that we might judge universes not only by the complexity of their rules and initial states, but also by the com
Re: Computational complexity of "running" the multiverse
From: "Eric Hawthorne" > One of the issues is the computational complexity of "running all the > possible i.e. definable programs" to create an informational multiverse > out of which consistent, metric, regular, observable info-universes > emerge. If computation takes energy (as it undeniably does WITHIN our > universe), then an unfathomably impossibly large amount of > "extra-universal" energy would be required to compute all > info-universes. Tree points here, or, maybe, three non-senses (in this case I apolozige). A) Is there a principle of conservation of energy in MWI? I do not think so. Does it mean that - in principle - you could have a world in which there is "omnipotence" or a very large amount of energy? B) Which is the role of observers in that "info-universal-computation"? Do they cooperate? Is such a computation a "participatory" computation (in the sense of Wheeler)? Possibility of delayed choices, anthropic "functionals", Banah-Tarski weirdness, and other amenities ... like http://www.arxiv.org/abs/quant-ph/0109022 C) According to Spreng the parameters are three: energy, time, existing information. Thus you can minimize energy by using more time and more information. s.
The Facts of Life
CMR wrote: Indeed. The constraints to, and requirements for, terrestrial life have had to be revised and extended of late, given thermophiles and the like. Though they obviously share our dimensional requisites, they do serve to highlight the risk of prematurely pronouncing the "facts of life". Just to be mischievous, I'll here pronounce "the facts of life" or more precisely "a sketch of a theory of the emergence of life" which will serve the purpose of partially constraining/ defining what is meant by life. This is a hobby project. The Emergence of Life Via Weak (Stochastic) Physical Pattern Replication == Definitions: "pattern" a form of order or regularity, which can be described by a finite and usually simple set of constraints. "living organism" is a subtype of "spatially organized pattern of matter and energy with some distribution for a time period in some spatial region" in otherwords, of "physical pattern in space-time". "ecosystem" or "supporting environment of an organism" is also a subtype of "physical pattern in space-time". "species" is also a subtype of "physical pattern in space-time", ranging over a larger span of time than an organism pattern, and which includes instances over time of the subpatterns of the "species" pattern that constitute the individual organisms of the species. Abstract: - The natural selection process that results in the evolution of lifeforms as we know them can be extended backwards in time further than is traditionally assumed, to fully explain the emergence of life from chance-occurring patterns of matter and energy. A model of the form of this earliest natural selection process is presented, in terms of three specific weakenings of the self-replication and metabolism processes that lifeforms exhibit. Characteristics of a living organism: --- 1. It self-replicates (aka reproduces). Part of what this means is that the organism assimilates surrounding matter and energy so that they become part of its species pattern, if not necessarily of its own "individual organism" pattern. 2. It metabolizes. It ingests matter and energy and converts them to a form more directly usable for the maintenance of the form and function of the organism pattern and for its reproduction. 3. It is an autonomous agent (within some environmental constraints.) The matter and energy that is "inside" the organism pattern can replicate the pattern, and metabolize pattern-external matter and energy, in a relatively diverse set of surroundings, compared to its own form and function constraints anyway, and it can do these things substantially "by itself" so long as an appropriate supporting environment (which may not itself qualify as an organism but has some form and function constraints itself) is maintained near it. In a sense, this "autonomous replicating and metabolizing" criterion just helps us define a boundary around what matter and energy is "the organism" to and what is "its environment". Thesis --- 1. Before there was "strong" "individual-organism" self-replication, there was "weak" (stochastic) replication of "weakly constrained" (and possibly physically dispersed) "pre-organism" patterns of matter and energy. The only property (constraint on form and function) that these patterns had to exhibit was just enough probability and frequency of just as roughly accurate pattern reproduction so as to maintain the order (i.e. the pattern constraints) of the "pre-species" pattern against the various forms of pattern-dissolution attacks that occurred in its environment. These attacks don't need to be explained much. They are comprised just of a.. the natural tendency of any physical system to increasing entropy (disorder) and b. active processes of dissolution of the pattern or its resources in its supporting environment where those active processes are the result of the actions of competing weakly-replicating, weakly-metabolising physical patterns in the vicinity. 2. Before there was "strong" "organism-internalized" metabolism process, there was "weak" (stochastic) pseudo-metabolism. That is there were processes of energy conversion (and temperature regimes and matter mobility regimes (e.g. liquid phases) ) IN THE VICINITY OF A WEAKLY REPLICATING PATTERN which were such as to support the (at least probabilistic) carrying on of the weak replication process of the pattern. That is, early metabolism could be defined as happening both within and in the environment of the pattern. Since the weakly replicating pattern initially may have been somewhat spatially distributed, and only stochastically present at various time intervals, it's just as well that we don't require that the pattern-supporting energy conversion processes (heat-engine processes) be carrried out initially entirely WITHIN the pattern (pre-organism) itself. Weak Replication and
Re: Tegmark is too "physics-centric"
Kory Heath, <[EMAIL PROTECTED]>, writes: > It is very likely that even Conway's Life universe has this feature. Its > rules are absurdly simple, and we know that it can contain self-replicating > structures, which would be capable of mutation, and therefore evolution. We > can specify very simple initial conditions from which self-replicating > structures would be overwhelmingly likely to appear, as long as the lattice > is big enough. (The binary digits of many easily-computable real numbers > would work.) Yes, I see that that is true. I think it points to a problem with some of the simple conceptualizations of measure, about which I will say more below.But let me ask if you agree that considering Conway's 2D Life world with simply-specified initial conditions as in your example, that conscious life would be extraordinarily rare? I want to say, vastly more rare than in our universe, but of course we don't know how rare life actually is in our universe, so that may be a hard claim to justify. But the point is that our universe has stable structures; it has atoms of dozens of different varieties, which can form uncountable millions of stable molecules. It has mechanisms to generate varieties of these different molecules and collect them together in environments where they can react in interesting ways. We don't have a full picture of how life and consciousness evolved, but looking around, it doesn't seem like it should have been THAT hard, which is where the Fermi paradox comes from. In many ways, our universe seems tailor made for creating observers. In contrast, in the Life world there are no equivalents to atoms or molecules, no chemical reactions. It's too chaotic; there's not enough structure. Replicators and life seem to require a balance between chaos and stasis, and Life is far too dynamic. It just looks to me like it would be almost impossible for replicators to arise naturally. Almost impossible, but not absolutely impossible, so if you tried enough initial conditions as you suggest, it would happen. I won't belabor this argument unless you disagree about the ease with which life might arise in a Life universe, and consciousness evolve. And the main point is that these are exactly the kinds of considerations which Tegmark discusses. Issues of stability of the building blocks of life, of providing the right amounts and kinds of interactions. These physics-like considerations are precisely the correct issues to consider in looking at how easily observers will arise, and that is Tegmark's point. I haven't read Tegmark's paper in detail recently, and to the extent that his arguments are based on string theory or QM then I would agree that those are too parochial. But as I recall he had a number of broad arguments that would apply even to a Life-like universe. Now I'll get back to the question above about measure. There are universes, as in your example, where life is intrinsically unlikely, but if you make the universe large enough, and provide all possible initial conditions for finite-sized regions, then in all that vastness, somewhere life will exist. The problem is, this is not too different from separately implementing alternate, smaller versions of that universe, with different initial conditions for each, so that all possible initial conditions are tried in some universe. A small fraction of those universes will have life. To specify just one of the life-containing universes will typically take a lot of information, while specifying all of the universes takes less information. This is analogous to the even broader picture of the "universal dovetailer (UD)" program, the program that runs all programs (on all initial conditions). It's a very small program, yet it creates all possible universes. Even universes with incredibly complex laws of physics and initial conditions are created by this extremely small UD program. Does this mean that all universes have the same measure, and it is large, since this small program creates them? The answer has to be no. It's not enough to find a small program which generates a desired structure, somewhere in the vastness that it creates. Otherwise all integers would have the same complexity because they are all created by a simple counting program. Wei Dai once suggested a heuristic that the measure of a structure ought to have two components: the size of the program that creates it; and the size of a program which locates it in the output of the first program. By this argument, you could have a big program which output just the structure in question, which was then located by a trivial one; or you could have a small program which output the structure among a vastness, which then required a big program to locate it. Either way, the structure has a large measure. This was the motivation for the idea I proposed a few days ago, that for applying anthropic reasoning, a universe should get a "bonus" if it had a high density of observ
