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Math Science

When Does the Universe Compute? 182

Posted by timothy
from the mice-were-quite-clear-about-this dept.
KentuckyFC writes "The idea that every physical event is a computation has spread like wildfire through science. That has triggered an unprecedented interest in unconventional computing such as quantum computing, DNA computing and even the ability of a single-celled organism, called slime mold, to solve mazes. However, that may need to change now that physicists have worked out a formal way of distinguishing between systems that compute and those that don't. One key is the ability to encode and decode information. 'Without the encode and decode steps, there is no computation; there is simply a physical system undergoing evolution,' they say. That means computers must be engineered systems based on well understood laws of physics that can be used to predict the outcome of an abstract evolution. So slime mold fails the test while most forms of quantum computation pass."
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When Does the Universe Compute?

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  • by Anonymous Coward on Tuesday October 08, 2013 @01:35PM (#45072513)
    "I'll get it," a wife said to her husband as the phone rang.
    On the line a pervert, breathing heavily, said, "I bet you have a tight asshole with no hair."
    "Yes," she responded. "He's sitting next to me watching TV."
  • Before we go into philosophy, I warn that being a computation is different from "being the result of a computation". The mold can be simulated.

    • by ackthpt (218170)

      Psst! It's an Analog Computer, they're way faster and more flexible than digital ones, but don't tell anyone or I'll be modded down into oblivion.

      • Analog computers are more flexible? Did you post this comment from an analog computer? Can I play candy crush on an analog computer?

        How are you defining flexibility?

  • by presidenteloco (659168) on Tuesday October 08, 2013 @01:42PM (#45072605)

    Why can we not think of the information as being embodied in "some aspect or other of" the matter and energy undergoing evolution. It is only some observer that needs to see the information as having been encoded or decoded.

    Metrics of computations, or measurements of information flows, may be a productive way of describing (and predicting) complex physical evolutions, regardless of whether the physical system itself is identifiably encoding and decoding information explicitly. You just have to establish your own observer convention for how you think the information is represented in the matter and energy under discussion, or you can even just think about "the maximum amount of information" that could be contained in that matter/energy/spacetime region, and the maximum possible amount of information flow there.

    • by Xaedalus (1192463)
      If I understand your argument, you're speculating that the universe is a pantheistic, evolving computation seeking entropy?
    • by Hatta (162192) on Tuesday October 08, 2013 @01:49PM (#45072717) Journal

      We only don't see the encoding and decoding steps because we are inside the system that is doing the computation. If the universe were a simulation, those inside the simulation would see a ball trace a parabola with no encoding or decoding steps. Those who designed the simulation would be well aware of those steps.

      • Balls don't trace parabolas. They trace ellipses where one of the focal points is the center of mass of the Earth. In order to trace a parabola, the ball would have to be travelling at around 11.2 km/s
    • by Artifakt (700173)

      When you try to define an observer in Physics, you run into a property of Quantum Mechanics. There, an observer is, for example, any outside particle that becomes involved in a state vector. When the state vector begins to impact what the particle is doing, that "collapses the vector", and the quantum state, which is until then is theoretically only a probablity, becomes an actual event, from the 'perspective' of that particle. You can also describe this process in terms of fields instead of particles, whi

    • this is a true statement:

      Why can we not think of the information as being embodied in "some aspect or other of" the matter and energy undergoing evolution. It is only some observer that needs to see the information as having been encoded or decoded.

      I think TFA (and Turing too, but we'll get to that) make a fundamental mistake that leads them to these TED-talk kind of wild eyed pop-science speculation.

      It relates to social construction of reality: http://en.wikipedia.org/wiki/Social_constructionism [wikipedia.org]

      So, my poin

      • by retchdog (1319261)

        information theory tells you the limits of what you can know, without regard for how hard it might be to get there. (actually it mostly proves upper bounds on these limits, but that's the style of it.)

        computation theory speaks of how hard it is to get there.

        if your opponents have only a classical computer and polynomial time, then you don't actually need a one-time pad (which is an information theoretic limitation); you can fake it, and they won't have enough time to unweave your trick. in the other directi

        • hey thanks for the response...it's clear you are more adept at handling the terminology of Computer Science.

          IMHO, though you are batting around heady ideas, it is all just language to describe **things we program machines to do**

          i'm not being reductive_it's recontextualizing fresh language to describe what we observe and, in that context **what we can predict and how**

          start with your introductory sentence...'X theory does 1, while Y theory does 2'...wrong...humans test hypothesis and program machines to exe

          • by retchdog (1319261)

            i'm sorry, but without definitions we're not going to get anywhere. it's been a while since my formal training in complexity theory, but i don't think i've committed any fundamental errors; i'm trying my best to both recall and summarize for a public forum, while you do nothing but bat around baseless assertions and try to insult me. there's nothing wrong with baseless assertions, but please don't assign them labels which you don't understand. consider refining your ideas into precise statements, rather tha

    • If you think the whole universe is a computer, then the phrase "I'm going to buy a new computer" is meaningless. There needs to be a differentiation between things that can be used for general computation, and other things (e.g. like the kind of computer that can only be used to compute how a particular slime mold will go through a particular maze at a particular time.

      If you don't need the information to be encoded/decoded because you can just "see it" in there like the matrix, that information still repre

  • Sounds like they are arbitrarily defining computing as a simulation of the universe, therefore the actual universe cannot compute. I think this unnecessarily limiting people's imagination.

    Besides, from the inside of a simulation its all real to you.

    • Re:Definitions (Score:4, Insightful)

      by gstoddart (321705) on Tuesday October 08, 2013 @01:55PM (#45072787) Homepage

      Sounds like they are arbitrarily defining computing as a simulation of the universe, therefore the actual universe cannot compute.

      Or that they're saying the universe doesn't need to do calculations to determine where a falling object is going -- it just falls according to the laws of physics and doesn't need to be calculated.

      I think this unnecessarily limiting people's imagination.

      Does 'imagination' in this context actually tell us anything? We know that we need to do calculations for this stuff, but how does the assertion that the universe isn't doing the calculations limit our imagination? Stuff happens according to physical laws, the behavior is inherent to reality. Nobody has to do the math, it just happens.

      Besides, from the inside of a simulation its all real to you.

      Very meta, and equally meaningless. Yes, if we were in a simulation, we'd likely never know.

      But given that we have no evidence to suggest we are, any assumptions around the notion that we are (or may be) are pretty much useless to us unless we can figure out the gaps in the simulation.

      To me the suggestion we're living in a simulation serves no other purpose that throwing out something wacky to stump people at parties, but otherwise doesn't seem to have any application to understanding our universe.

      • by Obfuscant (592200)

        Or that they're saying the universe doesn't need to do calculations to determine where a falling object is going -- it just falls according to the laws of physics and doesn't need to be calculated.

        Sounds like a Schroedinger's Cat of physical computation.

        Hold a bowling ball over a cat. Drop the bowling ball. The cat is either a live or dead, the actual state cannot be determined until something decodes the computation done by the falling (or not falling) bowling ball.

        "Damn, my printer jammed, we're overrun by half-dead cats." "We're half-overrun by dead cats?"

        • "Back in Nebraska, our cat got stuck in my brother's camp trunk, and we did not need to open it to know there was all kinds of dead cat in there." - Penny.
      • Re:Definitions (Score:4, Informative)

        by Sarten-X (1102295) on Tuesday October 08, 2013 @02:12PM (#45073023) Homepage

        doesn't seem to have any application to understanding our universe.

        If we are a simulation, we may be able to discern exactly what we're simulating, and why. Theology aside, even discovering that our universe functions like a simulation may allow us to seek out and utilize aspects of the simulation that are useful to us.

        Consider, for example, if we could simply access an information store outside our universe from anywhere within it. Even a single bit being accessible would offer the ability to have near-instant communications with other planets, or perhaps even other stars. If we could push matter out of or into the universe, we'd have an effective teleportation mechanism.

        Science is all about figuring out the rules of our universe. Being inside a simulation means there are other, possibly different, rules outside, so breaking out means we have new capabilities that are impossible within our universe.

        • > If we are a simulation, we may be able to discern exactly what we're simulating, and why.

          No wai and I can prove it.

          You have an mp3 player with two songs in it. The random playing algorithm makes it play the first song, the second song, the first again the second again and so on, because when it has to choose the next song there is only the other one available.

          The normal playing algorithm plays the first song then the second song then the first song and so on EXACTLY LIKE the random playing algorithm.

          Wi

          • by Sarten-X (1102295)

            Your "proof" only illustrates one particular case, which does not necessarily apply to the question at hand.

            It is indeed like Plato's cave, and the same lesson applies: Occam's razor is not always correct. Sometimes there are really weird truths, and with enough experiments, they can be discerned. Perhaps that MP3 player takes a little longer between songs while it tries to randomize the list. With a long enough recording of the playback at a high enough precision, the slight delay can be noticed, and that

        • by gstoddart (321705)

          If we are a simulation, we may

          I see ifs, maybes, what ifs, a few 'could bes', and wouldn't it be awesome if ... and nothing at all to suggest any of it is real or relates to our universe as we see and experience it.

          Science is all about figuring out the rules of our universe.

          Yes, yes it is.

          It isn't about saying "gee, if our universe wasn't really a universe, then all of these things could be true and I could have a pony".

          What you're describing is at best speculative fiction, and at worst just making shit up.

          • by Sarten-X (1102295)

            Yes, everything I said was speculative. No, I don't think we're actually in a simulation. That does not mean that such a thing has been proven impossible. Until it is, it cannot be dismissed as a theory to explain observations that don't fit existing theories.

            Science only deals in what we can see and observe

            That is not limited to what we can see or observe right now. Perhaps a future observation will reveal discrepancies in We could not observe the Higgs boson until long after its existence was theorized. In fact, I think your original post said it well:

            But given that we have no evidence to suggest we are, any assumptions around the notion that we are (or may be) are pretty much useless to us unless we can figure out the gaps in the simulation.

            B

        • > If we are a simulation, we may be able to discern exactly what we're simulating, and why.

          As a mystic the reason is quite simple: The growth and evolution of consciousness.

          There is one primary reason the [physical] universe exists: Relationships.

          What, you thought human consciousness was the only kind !? There is NO-THING BUT consciousness.

          See Peter Russel's excellent talk:

          The Primacy of Consciousness - Peter Russell
          http://www.youtube.com/watch?v=-d4ugppcRUE [youtube.com]

          • by mestar (121800)

            It's promising in the first 25 minutes but then he wedges in "remote viewing" as a fact, and then it all falls apart.

            Nothing later explains the world better, no predictions from his model where he puts consciousness into single atoms and similar bullshit.

      • by Artifakt (700173)

        I have absolutely no interest in learning if I exist inside a simulation or not, unless it's programed with accessable cheat codes.

      • To me the suggestion we're living in a simulation serves no other purpose that throwing out something wacky to stump people at parties

        ... whoa... </neo>

    • Yeah from the article it seems they worked things out by writing a pet definition. There no experiment here. No observation. No math even. This is physics that could be done by lawyers.
  • by naasking (94116) <[moc.liamg] [ta] [gniksaan]> on Tuesday October 08, 2013 @01:49PM (#45072725) Homepage

    The type of computation discussed in this article is not the type of computation used in the phrase "every physical event is a computation". These physicists are trying to discern computation from physical processes by discerning whether the process can encode information in its initial conditions, and other information can be extracted from its results. This is good when trying to determine which processes lend themselves to building computers, but it does not address the question of whether the universe is a computer, and whether the laws of physics are merely closed form equations describing some of its operational semantics.

    • imo, the entire discussion and investigation comes down to one question: How do you define information?
      IF DNA is encoded information and keeping a similar DNA 'alive' for billions of years is considered success (a Species is kind of a generalized unknowable DNA), then slime mold is successful. The randomization of sexual reproduction where all the stuff gets shuffled all the time (between generations), is one method of 'predicting' the randomness of the future. Or atl elast dealing with enough to get a goo
    • but it does not address the question of whether the universe is a computer

      b/c, IMHO, 'computing' is the act of programming a machine with instructions

      that's all 'computing' is...asking if the universe is a 'computer' is like asking if it is a 'Volksvagen'....they are both just analogies of types of systems

      whether the laws of physics are merely closed form equations describing some of its operational semantics.

      as opposed to what?

      how could 'the laws of physics' be anything other than humans attempt to make he

      • by cowdung (702933)

        Computing is not the act of programming.. Computing is the act of executing a program.

        In my opinion, this is a question for Computer Scientists and not Physicists.

        • Computing is not the act of programming.. Computing is the act of executing a program.

          programming is not computing?

          when I write a python script, that isn't under the umbrella of human activity we use the word 'computing' for?

          you're dead in the water on this one...I'd like to have a discussion about this topic but this is not that

      • by naasking (94116)

        b/c, IMHO, 'computing' is the act of programming a machine with instructions

        Computing and programming are not synonymous. Whether a machine is a programmable computer is a completely separate question from whether it's a computer at all, ie. the universal Turing machine vs Turing machine distinction.

        as opposed to what?

        Reality could compute uncomputable functions (like functions on the reals). That would make natural laws super-Turing, ie. Turing + Oracle. The Oracle isn't a computer as we currently define i

        • Thanks for the response.

          I think my whole point is that Turing's concepts should be done away with...so when you say this:

          Whether a machine is a programmable computer is a completely separate question from whether it's a computer at all, ie. the universal Turing machine vs Turing machine distinction.

          I want to scream (the truth)...the discussion itself (like the one we're having) begins to resemble a meta-Turing Machine itself...then I feel crazy inside....

          Turing is as Turing does. Anything can be 'Turing-com

  • by Sique (173459) on Tuesday October 08, 2013 @01:57PM (#45072825) Homepage
    It's much more complicated than that. Myxogastria can be onecelled and mononuclear, and they can be multicelled and multinuclear, and they can even be onecelled and multinuclear - all within the same organism. A single plasmodium cell can contain up to 10 mio nuclei and span several square meters. Thus it would be better to call the plasmodium acellular, as it has no inner cell structure.
  • by Empiric (675968) on Tuesday October 08, 2013 @01:58PM (#45072833) Homepage
    For example, the processes that slime mould uses to solve a maze are largely unknown. For this reason it is not computation.

    Don't we usually declare characteristics of things based on what we know about them, rather than on the basis of not knowing about them?

    Seems like a strange kind of subjective solipsism--"what is, is dependent upon on what I currently know is".
    • by nashv (1479253)

      Yeah, who the hell are these authors anyway? Engineers?

    • Don't we usually declare characteristics of things based on what we know about them, rather than on the basis of not knowing about them?

      I'm Donald Rumsfeld, you insensitive clod!

  • See subject.
    • by Suiggy (1544213)

      Agreed. The authors of the papers are just old biologists who don't like the idea of pancomputationalism and digital physics infringing upon their domain. They want the magic of life to remain elusive. The truth, however, is that computation *is* the magic they so desire.

  • BS (Score:4, Interesting)

    by nashv (1479253) on Tuesday October 08, 2013 @02:00PM (#45072869) Homepage

    I RTFAed. Their theory is essentially that computation can only be said to have occurred if you know the physical nature / laws that allowed the computation to occur.

    Which is BS. There are plenty of people who can add 2 numbers on a calculator without knowing anything about electrons, bits, electronics etc. You can extend that until the number of people who understand specific physical laws underlying a computation is zero.

    Since when is human knowledge the test for whether any computation is happening? All they are saying is "If we don't understand it, we will not call it computation." Way to go with the semantic circus.

    • They're trying to draw a distinction between computation and experimentation. Essentially, they're saying that if your model/mental-map of the problem is good enough, i.e. you have good predictive power over your methods, then you are performing a calculation/computation. If you're not so certain of the outcome, then it's experimentation. But I do agree, it's kind of a semantic knife's edge.
    • Since when is human knowledge the test for whether any computation is happening?

      Are you sure anyone's referring to human knowledge? I've only skimmed it but got the impression that their criterion is that there is some information (in the new-fangled sense) to be had at the end of it - it doesn't have to interpreted by a human, it simply has to be available (to a human, or a cat, or a particle in the vicinity).

      • by nashv (1479253)

        There is always information around (new-fangled sense). In fact, Any dissimilarity in the universe of any kind is information. Presumably, the ability to recognise such dissimilarities is required for any information retrieval, and in the end humans must detect it if we are to talk about if it is computation or not.

        The point they are making is that one must understand a systems physical laws governing events for it to be a computation. Wrong. What they say actually applies to the fact that we must understan

  • I think whether or not the Universe computes is relative.

    What is it you're trying to compute? If you are trying to compute the dynamics of the Universe then the Universe does compute. It computes itself better than any other model.

    If you are talking about abstractions then probably computers do very well give proper instruction and dataset.

    To get a computer to compute the universe is like trying to force a very large round peg into a very small square hole.

  • "God does not care about our mathematical difficulties. He integrates empirically." --Albert Einstein
  • by sycodon (149926)

    Slashdot is slipping. Twenty Five posts and not one mention of Douglas Adams.

    • We're all waiting to claim post 42, of course.
    • by dgatwood (11270)

      The mice were mentioned in the "department" line, so we assumed we'd be modded redundant. But as long as we're going down that path....

      Ooh. I know this one. The computation stops when we get bulldozed to make room for an intergalactic superhighway.

    • I'm shocked, shocked and dismayed, that I had to scroll down this far to find that someone had beaten me to it.
  • Slime mold senses its environment and reacts accordingly. That is computation in the broader sense used by physicists. It isn't engineered (unless you are of a certain ilk) but it is an organized, coherent system.

  • I.e., the idea of the entire universe as constituting some sort of universal computational substrate.

    The idea is probably wrong, mainly because every "my conception of the fundamental nature of the universe based on just discovered science" is wrong, due to the time-bound nature of our perceptions.

    • >The idea is probably wrong, mainly because every "my conception of the fundamental nature of the universe based on just discovered science" is wrong...

      probably wrong but not necessarily wrong.

      Maybe, if people keep coming up with new kinds of science (pun intended), one new theory will finally get a lot of the rest of the unknown bit (pun not intended) right.

      Just because computing is the "latest thing" does not mean it is not a better analogy/explanation of certain things (minds, big chunks of physics) t

  • By defining computation to be X and not Y, I have proved that X is computation and Y is not.

    Yes, terribly helpful, that.

  • Does this remind anyone else of how religious philosophers of days past used to argue over how many angles could dance on the head of a pin? I'm not sure about the angles part, but there are surely some pinheads in this story.

  • However, that may need to change now that physicists have worked out a formal way of distinguishing between systems that compute and those that don't. One key is the ability to encode and decode information. 'Without the encode and decode steps, there is no computation; there is simply a physical system undergoing evolution,' they say. ... So slime mold fails the test while most forms of quantum computation pass."

    The slime mold is computing the optimal solution to the task at hand. Evolution is the computa

  • Physicists, please leave this to computer people. Interpretation is just a transformation, and is no magic door to computational efficiency.

    If a slime mold could, via interpretation, solve some NP-Hard problem, that would be an astounding result with major implications for the computational ability of the universe.

    This is independent of the interpretation. It is the equivalency of reducing a problem to another, of which physicists are indeed well aware.

  • by gweihir (88907) on Tuesday October 08, 2013 @03:27PM (#45074017)

    "A physical system undergoing evaluation" is pretty much what a computation on a physical device looks like. Seems some physicist(s) with their usual search for meaning when the midlife-crisis strikes but little idea of Computer Science drummed something up that does not make a lot of sense. The issue is of course that the encoding and decoding steps (properly called abstraction and application) are only necessary when you have a computing device using a different primary mechanism that the device the calculation apply to. For example, when doing analog computations in a radar system, you do not change the mechanism, the signal already is electrical and analog. Hence when doing, day, computations for gravity, there would well be an invisible tiny "gravitational computer" in any particle affected by gravitation that uses the available input directly.

    Of course, there is always the (likely) possibility that this whole universe is only a simulation, and all perception of it we have is a cleverly crafted illusion. In that case the abstraction step is not necessary either, except possible in the bi-directional channel that delivers the illusion to each of us. (Solipsists win the most here: Only one bi-directional channel needed for the whole universe ;-)

  • In the 18th century, the sexy model of the universe was a clockwork mechanism because that was the coolest tech available at the time. Move forward three centuries and suddenly the universe is a digital computer because that is the new trendy tech. Never mind that 50 years ago Feynman showed that the universe is not efficiently computable by a Turing machine...

    • by nashv (1479253)

      This is what Feynman said

      ""It always bothers me that, according to the laws as we understand them today , it takes a computing machine an infinite number of logical operations to figure out what goes on in no matter how tiny a region of space, and no matter how tiny a region of time. How can all that be going on in that tiny space? Why should it take an infinite amount of logic to figure out what one tiny piece of space/time is going to do? So I have often made the hypotheses that ultimately physics will n

  • However, that may need to change now that physicists have worked out a formal way of distinguishing between systems that compute and those that don't.

    Just because a bunch of physicists propose such a "formal way" doesn't mean that that formal way is actually correct or even meaningful. The history of science is littered with physicists proposing all sorts of things outside physics, almost all of which have turned out to be b.s.

  • Philosophers tend to want to create specialized definitions and terms in order to project that philosophy so that it can be more broadly applied. I think this is what we are seeing here. In specific they mentioned slime mold and encoding and decoding. Actually slime mold is encoded with DNA and the function of the slime mold in navigating the maze reveals the decoding expressed as the function of slime mold. If our human abilities were more advanced we should be able to determine the future funct

  • Computation is essentially the same process. A computation uses the evolution of a physical system to model an abstract theory.
    But this only works when the link between the real and abstract worlds is clear and well understood.

    Yet strangely I can work computations using pen and paper using only the evolution of the poorly understood system consisting of my brain, arm, hand and eyes.

  • Maybe that'll throw a monkeywrench into the viral notion that we are living in a simulated universe [wavewatching.net].

    Not holding my breath though.

  • "The idea that every physical event is a computation has spread like wildfire through science."

    Not that it's necessarily true, but I think it would have made better science fiction had The Matrix claimed that humans were computation units in the Machine's world, rather than that "battery" stuff.

    [Morpheus voice]
    What an amusing reversal... Which lane is fastest through this interchange? How many people get in the elevator? Have the soup or the salad? Tastes great or less filling? Our surroundings are enc

  • does not compute.

  • by ihaveamo (989662)

    That was a yummy SLIME MOLD!

    I know Nethack was an old game, but I didn't know it was written with organics...

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