Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

DETERMINISM OR RANDOM? Pick a side

  1. Jan 16, 2012 #1
    Einstein strongly believed in determinism. Some physicists today like Michio Kaku are leaning toward indeterminism.

    I have many of my own reasons but I'm on Einstein's side.

    I want to discuss, not fight. Listen to what other posters have to say before refuting it.
     
  2. jcsd
  3. Jan 16, 2012 #2
    The uncertainty principle only shows that we cannot know the position and momentum of a particle at any time for certain, it does not mean its position and momentum are not certain.

    Meaning the domino effect of action/reaction holds true on all scales, just because we don't understand them fully does not mean we should call them random.
     
  4. Jan 16, 2012 #3

    Ken G

    User Avatar
    Gold Member

    In my view, it's not an either/or issue. Both determinism and randomness are just models, ways we use to think about what is happening. What is actually happening does not need to be either one, and unlikely is. The scientist only has access to these two types of models so far, yet in my opinion, the only thing more absurd than imagining that what happens is truly random is imagning that it is truly determined by what has already happened.
     
    Last edited: Jan 16, 2012
  5. Jan 16, 2012 #4
    I hear what you're saying, but it is most obviously one or the other. Things either happen for a reason or they don't. They are either random, or not to some degree. So really you have to pick a side in terms of physical interactions.
     
  6. Jan 16, 2012 #5
    Um... I'm afraid PBS Nova or BBC (or Brian Greene/Lisa Randall) or what have you have given a completely incorrect impression. Indeterminism in quantum mechanics is certainly *not* some new fangled idea that people are toying with at the frontier of physics. It is a central aspect, as far as we understand it, of quantum mechanics. Quantum mechanics was developed in the 1920's, more or less finished by the 1950's, that's 60-90 years ago. Einstein never liked quantum mechanics and wrote a list of, what he felt, were absurd results that quantum mechanics predicted that he thought were proof that quantum mechanics was not complete. What Einstein thought were "contradictions" are now called Einstein's (and Podolsky and Rosen) PARADOXES. Why? Well because he was wrong on every point, all these things he couldn't believe were possible ARE possible and have been verified many times. Einstein was simply wrong about quantum mechanics but this is not NEW.

    The problem (well one of many) with these pop science accounts (Brian Greene, PBS Nova, etc.) is that they conflate frontier/speculative physics like string theory, with extremely old and established physics like relativity and quantum mechanics. The whole Einstein vs. QM debate was resolved before even my FATHER was born and is a dead horse that has been dealt additional blows throughout the decades (the most significant recent blow I believe being by Alain Aspect and his Bell's inequalities experiments).

    This is not to say that there aren't still open interpretational issues in quantum mechanics but any framing of it as Einstein vs. String theory is COMPLETELY incorrect, Einstein WAS wrong about QM and the interpretational issues of quantum mechanics have NOTHING to do with string theory (and are very old). If anything you could say it was Einstein vs. Bohr way back in the 1930's and Bohr was right.

    However, determinism vs. randomness as a general debate is one that continues on but the forms and considerations have grown far beyond those founding fathers of quantum mechanics. The central issue now is that we have essentially reduced the issue to the following: There CANNOT be a hidden determinism in quantum mechanics without breaking causality and special relativity, we have literally tested quantum mechanics billions of times (you do it every time you use a digital device), we have never observed a violation of causality or special relativity (ulta-new neutrino data not withstanding). So the only way to reconcile determinism with quantum mechanics is to break some other physics that we have absolutely no reason to suspect is incorrect. Regardless, this has nothing to do with Michio Kaku (see P.S.) or string theory and is certainly not a new frontier


    P.S. Also, an FYI, in general people who present popular science AREN'T actually particularly noteworthy physicist, the theories that Michio Kaku describes to you aren't HIS theories and he's not like the leader of the people who push these frontiers, rather the people who push these frontiers think very little of such a person since the public ends up perceiving them as *great* physicists because they spend LESS time actually doing physics and MORE time doing things like TV spots and radio interviews
     
    Last edited: Jan 16, 2012
  7. Jan 16, 2012 #6
    What about the "birth" of the universe or even conscious intent, choice, or decision (assuming one believes in free will)? I mean, are these random/indeterministic or causally deterministic? I'm not sure either one applies?
     
  8. Jan 16, 2012 #7
    You don't *pick* sides. This is science, specifically physics. As a layman you see things as "well apparently Einstein said this and he's supposed to be really smart but some other guys says this, who do I trust?" However, physics is both a collaborative effort and a quantitative one. There's not proof by authority, the only proofs are by math and experiment. The current state of math and experiment is firmly on the side of non-determinism and to salvage determinism the amount of physics that would have to be wrong and rewritten would be quite staggering.

    However, if you really want to reduce things to who said what, as I said in my previous post, IF quantum mechanics were deterministic "Einstein's" (sorry Lorentz, Poincare, Minkowski, etc.) special relativity would have to be wrong. So for "Einstein to be right" about quantum, as you say, he'd have to be wrong about "his" special relativity.
     
  9. Jan 16, 2012 #8
    Einstein may have been wrong about aspects, but the fact that we know SO little about many of the phenomenon observed at the quantum level means that we CANNOT, and COULD NOT, rule out either determinism or indeterminism based on our current understanding of quantum mechanics. In fact truly it means that our understanding can provide VERY little insight on the subject, atleast until we actually know what half the things we observe are.

    I also NEVER implied that it was EINSTEIN VS STRING THEORY, when i mentioned Einstein and Michio Kaku, all i was doing was showing that the topic is one continuously debated by physicists.

    I also NEVER implied that quantum indeterminacy was a new concept.

    The facts are that the things we do observe only appear to grow in complexity the more we observe them. So I ask, do you believe the complexity within interactions is random or deterministic?

    ( and on a side note, dont worry i know michio kaku is obviously just trying to gain fame)
     
  10. Jan 16, 2012 #9
    For a possible deterministic description of QM see:

    arXiv:1111.3319 [pdf, ps, other]
    de Broglie Deterministic Dice and emerging Relativistic Quantum Mechanics
    Donatello Dolce
    Comments: 10 pages, 7 figures, talk given at DICE2011 (Space-Time-Matter), minor corrections
    Journal-ref: J. Phys.: Conf. Ser. 306 012049 (2011)

    "Similarly to a particle in a box or to a vibrating string, relativistic fields can be quantized
    by imposing their characteristic de Broglie periodicities as constraints [1, 2, 3, 4, 5, 6, 7]. In
    this way elementary systems can be thought of as ”de Broglie internal clocks”, that is, as
    relativistic fields with intrinsic dynamical de Broglie time periodicities Tt . Even for a light
    particle such as the electron, this intrinsic time periodicity (also know as zitterbewegung) is
    extremely fast (T_t \sim 10^{−20} s), many orders of magnitude away from the present experimental
    resolution in time. As in a dice rolling too fast with respect to a given resolution in time, these
    de Broglie internal clocks can only be described statistically. It can be shown that the effective
    statistical description emerging from such periodic dynamics matches (without fine tunings)
    ordinary relativistic Quantum Mechanics (QM) [1].The idea is similar to the ”stroboscopic
    quantization” [8] or to the ’t Hooft determinism [9]. At the same time the underling classical-
    relativistic physics seems to solve many conceptual difficulties of the canonical quantum theory.
    In particular they do not involve any local-hidden-variable so that we can actually speak about
    deterministic quantization....."
     
  11. Jan 16, 2012 #10
    Also when you view all of these topics from a more outside perspective, rather than trying to find answers within current understandings, it is obvious that there is order in the universe, such as self-similarity in nature. For one to say indeterminacy is the answer, you would HAVE to say that randomness produces laws, imitations, and even concious thought.

    I think this way of thinking is what spurred Einstein into being "convinced" that he does not play dice. ( And by "he" I do not mean the common religious understanding of god)
     
  12. Jan 17, 2012 #11
    Listen, a lot of people on here know more about physics than me guaranteed, but it is obvious that detailed knowledge is not required to understand or even produce intelligent theories. ( Newton, Einstein,). Even M-theory requires a largely different perspective of things than most would consider the norm. These things are derived from logic, and logic is the only thing which allows us to support them. Hence a logical argument is without a doubt a justified one.

    I believe Einstein inspired many in this way by thinking simply, to derive a theory which most would not deem simple.

    So when i talk of indeterminacy as being something i disagree with, it is not because i am unaware that there is mathematical and logical evidence supporting it. Just that if determinacy were true, it would UNDOUBTEDLY, require a much higher level of detail and understanding than humans are currently capable of to prove or even evidence it mathematically.

    Which leaves logic as its last defense. Dismissing it based on our current mathematical understanding would be like a 3 yr old telling max planck he was wrong based on his findings. In our case the 3 yr old being humans, and max planck being "the reason that manifests itself in nature", as Einstein put it.
     
  13. Jan 17, 2012 #12
    In a dice the outcomes are random but, if observed in slow-motion, also pre-determined by classical mechanics and initial conditions. Mathematics show that in QM something similar happens. The indeterminacy could be a problem of resolution in time.
     
    Last edited: Jan 17, 2012
  14. Jan 17, 2012 #13
    The outcomes of a dice aren't random at all? The variables are just very minute and too complex for us to predict. So the fact that a random dice throw isn't random. In itself should show that its smaller constituents that decide its outcome are not random.

    Logic itself denies indeterminacy, while indeterminacy denies logic.
     
  15. Jan 17, 2012 #14
    and halycon-on, what do you think about it?
     
  16. Jan 17, 2012 #15
    Sorry just re-read ur message. You are a determinist. And what you said is OBVIOUSLY true hahah
     
  17. Jan 17, 2012 #16
    Think about the first time the word random was ever used. Lets say a version of it was used by a cave man 14,000 years ago, he would have said the full moon was random.

    Little more info, it aint random.

    He would have said getting sick was random.

    Little more info, it aint random.


    THE WORD RANDOM WAS ONLY EVER CREATED DUE TO A LACK OF UNDERSTANDING.

    Random is only what we call things when we do not fully understand them. Tell me a situation in which you fully understood how a system worked, but then did not go on track.

    If you can, i will again guarantee you, that whatever made it not go on track, was just something you missed.
     
  18. Jan 17, 2012 #17

    Ken G

    User Avatar
    Gold Member

    All of physics was only ever created due to a "lack of understanding," that's the whole point of physics, and why we call them "models" and "theories." The same is true of determinism-- just another type of physics model, and the word was only ever created due to a lack of understanding (consider Newtonian physics re quantum physics). Also, you are wrong that the reality must be one or the other-- we have heard examples above that were neither, and one that was both. Indeed, it's not even clear that scientific theories have to be one or the other-- the debate rages as to which one quantum theory is, and even that is just a model of reality! Personally, I find it vastly unlikely that reality is either of the templates that we fit it into for our various purposes, it certainly doesn't need to be for physics to work on what it works on.

    To make this point more concrete, I'll choose one of the myriad of examples I could choose: chaotic phenomena. Now, I realize that someone who doesn't understand what I'm saying will jump up and say that chaotic dynamics are "actually deterministic", we just can't predict them because we don't have the precise knowledge of the initial conditions. But this is incorrect, it is the common mistake of confusing a particular model of chaotic phenomena (which is deterministic, say classical chaos theory) with actual chaotic phenomena (which we have no idea is deterministic, or "truly random", or neither one). Indeed, as soon as we bring in quantum mechanics, we get right back to the debate that rages in quantum mechanics itself, but even that misses the point-- for that's just a model too, as I said. Actual chaotic phenomena do not need to be either random or deterministic, but we can try to model them either way, and do in various contexts-- and to varying levels of success or failure.
     
    Last edited: Jan 17, 2012
  19. Jan 17, 2012 #18
    Ken g, physics is based on logic. The word random is based on " we don't understand the logic". or more like, "we think there is no logic in the way things work"

    So if physics is based on logic. But according to indeterminists there is no actual logic because everything we think is all derived from random particle interactions within our brain.

    We already know free will is an illusion. You just have to ask if this illusion is random or not.
     
  20. Jan 17, 2012 #19
    "we have heard examples above that were neither, and one that was both."

    I disagree with this entirely. I have heard no such thing. Point out your examples and i will tell you why they are one or the other.
     
  21. Jan 17, 2012 #20
    Give me an example of truly chatoic phenomena? One that couldn't easily be accounted for due to a lack of understanding of how the phenomena occurs
     
  22. Jan 17, 2012 #21
    As for us not knowing about quantum I think you're drastically misinformed about the state of quantum mechanics. As has been said quantum mechanics is quite old and extremely well understood on a practical level. There exist no mysteries in terms of its ability to predict reality, it is neither a new nor a "shaky" field, it is in fact the opposite, it is the most quantitatively successful theory in the history of mankind. It's simply metaphysical weird. It correctly predicts experiments, it tells us that our everyday classical world should obey the laws it does (i.e. the equations of quantum mechanics become those of classical mechanics when energies and systems are large). It's done, it's old, it's accurate as can be and it says the world is non-deterministic. It is by no means a work in progress. Plus, the theorems that forbid a (local) hidden variable theory (i.e. a deterministic theory that doesn't break special relativity) are extremely general, more general than quantum mechanics, they essentially put a constraint on what is called "local realism".


    And as to the ability of a layman to interpret the situation I would strongly disagree with your assertion that you can come to understand it (and I'm not quite sure why you list people like Newton and Einstein as 'everyman's" Newton held the most esteemed professorship of mathematics at Cambridge university and was the head of the royal academy of science, Einstein has a PhD in physics and was looking for a faculty job before taking a job as a patent clerk (which is a high paying job that requires an advanced degree in physics or engineering) because his first kid was born, his plan was to get a few papers out and try again for a faculty job, a strategy that worked out VERY well). If you don't understand the math, you simply can't understand what the issues are. The math doesn't hide the real concepts it IS the concepts.

    P.S. You REALLY shouldn't post so many messages in a rant like fashion, you're clearly very curious about physics which is good but that's the kind of thing that gets you banned.
     
    Last edited: Jan 17, 2012
  23. Jan 17, 2012 #22
    Um.... any quantum mechanical system... That's the WHOLE POINT. Quantum mechanics is NOT a theory about US not knowing the position and momentum of an electron, it's a story about the UNIVERSE not knowing the position and momentum. Quantum mechanics IS NOT secretly governed by classical mechanics, that's simply not what is at all and that's truly fundamental.

    If you would like specific examples, taking only a minute to think about them:

    -Stimulated Emission
    -Spontaneous Emission
    -The Results of a Stern-Gerlach experiment
    -Any of the Bell's inequalities experiments
    -Alpha decay
    -Beta decay
    -Gamma decay
    -Any decay
    -Single particle slit experiments on light
    -Single particle slit experiments on electrons
    -Single particle slit experiments on buckyballs (C-60)
    -Positional measurement of a particle in a box
    -Momentum measurement of a particle in a box
    -Transition amplitudes for any tunneling event
    , etc.
     
    Last edited: Jan 17, 2012
  24. Jan 17, 2012 #23
    I didnt know you weren't allowed to post heaps of messages, it will be one at a time then :p Thanks

    Also, there is something fundamental you are forgetting when you speak of quantum mechanics as being so sound that the maths behind it excludes the idea of determinism.

    Here is the fundamental thing you missed:

    "If you think you understand quantum physics, then you don't understand quantum physics"- Richard Feynman

    Also when you say the maths is the concept so to understand the thing you must understand the maths. This must be true on many levels. But also leaves out the fact that the concepts AND the maths are only based on what's right infront of us, and are only created by US.

    And whats right infront of us, is a world in which we KNOW, the interactions on our larger scale are a direct result of the interactions that occur on the subatomic scale.

    We also know that when you divide a number in half over and over it will never reach zero.

    We have also NEVER been presented with evidence that suggests that the smaller scales ever stop. Every time we've looked closer in history we have found that the material is made of the chain made of the molecule made of the atom made of the subatomic particles. This could continue forever, and is just as likely, and makes more sense then if it were ever to stop.

    So now you tell me, when facing INFINITY, does one brush the infinite explanations for the things they are seeing away, and stick to one narrow minded way of thinking regarding them??

    Also answer this, if indeterminacy is real, then why do we participate in physics? Are we trying to understand something with no meaning? Trying to figure out how the things work, even tho we already figured out that they work sometimes, and act differently others? just work and do **** because they just do and there is no reason behind it
     
  25. Jan 17, 2012 #24
    How can you say any kind of decay is truly chaotic, when half lives are fairly predictable? How can you say anything is truly chaotic, when others are not?

    For something to be truly chaotic, everything would need to be truly chaotic. Everything would need to be indeterminacy. Every physical law, every interaction. All of it would be utterrly useless. It would have either popped up randomly or would have always been there, always acting randomly.

    Like you say maths is the concept. Yet if the concept can be viewed without maths, by people. And maths is nothing more than a logical arrangement of peoples thoughts. Then maths is as much evidence as logic. Its when you have the two unified that something becomes believable.

    And i can assure you, quantum mechanics has not unified maths and logic
     
  26. Jan 17, 2012 #25

    Ken G

    User Avatar
    Gold Member

    It appears that your fundamental thesis here is that if we cannot positively rule out that something might be deterministic, then we should regard it as deterministic, and say we just don't understand it. What kind of logic is that? That's not an argument, it's a philosophical commitment, to a degree that is not at all unlike a religious faith. But science is not really all that interested in trying to shake your philosophical commitments, or your religious faiths. If you want to maintain that the universe is truly deterministic, you can always do that-- you could have done it in Aristotle's day, in Newton's, in Einstein's, and in the year 2450, had you been alive then. But what we are really talking about here is physics, and in physics, we don't ask if we can positively rule out determinism, we ask, what has determinism done for us lately? That's a scientific kind of question-- what does the model accomplish? Certainly determinism had its day, and continues to be a widely successful concept. But it has also exposed some limitations, in terms of our modern physics. That's the point, not that we now know determinism can't be right (we could never know that, how do you think we ever could?), but that we have stopped finding value in clinging to the concept.

    Randomness is similar-- many physical theories used randomness as part of the theory (statistical mechanics, thermodynamics, chaotic dynamics, etc.), and have done so for centuries. These are aspects of a theory, not aspects of reality. We don't get the latter, that's not what physics does. Yes, sometimes a statistical theory that invoked randomness turned out to be underpinned by a more fundamental theory that invoked determinism, and sometimes a deterministic theory turned out to be underpinned by a more fundamental theory that invoked randomness. And so on-- why should we ever expect that state of affairs to end? Are you one of the people who believes there is an "ultimate theory" that explains everything, and that this ultimate theory will have to be deterministic? On what basis do you hold this religious faith of yours? (Oh yeah, you base it on the fact that people said Newton couldn't do what he did, etc.-- but as I said, that's quite a flimsy basis for your logic.) The actual truth is, we have no diea, and I doubt we ever will, but that's fine because that's never what physics was about knowing. Physics was, is, and will be, about making models, and we will invoke whatever concepts we need at the time, be they deterministic, random, or who knows what else.

    Here we have your other main thesis: determinism is the only thing that can grant meaning to physics. That is really pretty way off target. You might not realize this, but when Newton first came out with his deterministic laws, many physicists were very disappointed in it-- they actually said it wasn't physics at all! That's because all it did was connect the final state to the initial state-- there wasn't anything that the dynamical equations could add, if all the information was already there in the initial condition! So they said the dynamical equations weren't actually telling us anything, they were just pushing back the "meaning" (as you put it) to the initial state, which was still unexplained! So much for the "meaning" in determinism. Of course, nowadays we don't fret that the information is in the initial conditions, and the dynamical equations only propagate this information forward in time, because we have discovered the power in being able to do that. So we changed our concept of what physics was supposed to able to do, and ran with that ball.

    Then the same thing happened again in quantum mechanics, except this time the "ball" we had to run with was indeterminism, and so again we changed our concept of what physics was supposed to do. And so on. This is all perfectly natural, it's just how physics works. We have no idea where the next turn will be, but we find "meaning" all along the path-- and we have no reason whatsoever to equate meaning with determinism, that's actually a rather limited and possibly even uneducated view (I don't mean to be harsh, I think your view is rather common) of what physics has done and can do.
     
    Last edited: Jan 17, 2012
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook




Loading...