[HN Gopher] Does quantum theory imply the universe is preordained?
___________________________________________________________________
Does quantum theory imply the universe is preordained?
Author : pseudolus
Score : 56 points
Date : 2023-12-19 16:06 UTC (6 hours ago)
(HTM) web link (www.nature.com)
(TXT) w3m dump (www.nature.com)
| gavinray wrote:
| When I was a teenager I had an idea:
|
| If you rolled marbles down a hill, assuming that identical
| starting conditions were applied each time, then the marbles'
| paths and final position would be the same each time.
|
| This also implies that if you know the starting conditions, you
| could calculate the state of any point in time from there.
|
| It made me curious whether you could apply this same logic to our
| universe -- though I get the feeling it's not quite as simple a
| system as marbles on a hill.
| EA-3167 wrote:
| The fundamental question here is whether or not you can get
| identical conditions in the first place. If for example
| spacetime is quantized, then it might be that the basic unit of
| our reality displays the sort of quantum behavior that makes it
| so hard to predict outcomes. It wouldn't just be a complex
| system, it would be an essentially random and ever-changing
| system. By the same token it could be the opposite, maybe it's
| just a _really_ complex system as you were speculating about,
| and while nothing is random, it 's essentially impossible to
| predict.
|
| In essence, is this a universe where a version of Maxwell's
| Daemon could conceivably exist, or is it a universe that even a
| god-like being would find random?
|
| https://en.wikipedia.org/wiki/Maxwell%27s_demon
| sim7c00 wrote:
| i think for physical systems this might hold true in some way,
| though, i am not a physics person at all. it just 'feels' that
| way to me. however, life is also there, and life doesnt
| nessesarily follow such rules, as actually most of
| (intelligent?) life is not physical. (emotions, thought etc.)
| but does have impact / effect on the physical. i dont think non
| physical things are so determenistic. (maybe they are, but it
| doesnt 'feel' that way to me)
| sheepdestroyer wrote:
| What makes you say that life is not physical?
|
| There seems to be no reason to believe that it's not.
|
| On the contrary it seems most plausible that everything,
| including emotions, thoughts, decisions, are just chemical
| and electrophysical reactions. Thus deterministic.
| tedivm wrote:
| If those physical reactions occur at or are influenced by
| the quantum level then they stop being deterministic. Hence
| the article.
| digging wrote:
| For classical physics it's basically true[1]; see Laplace's
| demon. I recall also independently inventing determinism as a
| kid after I realized how easily I'd been swayed by external
| factors into buying one toy over another.
|
| For non-physical things, such as emotions and thought...
| well, we have no actual proof they're anything but physical.
| We just don't have proof that they're _entirely_ physical,
| either. But the simplest explanation is actually that they
| are completely physical processes and just as deterministic
| as everything else (which is to say, possibly not at all,
| depending on how QM is resolved).
|
| [1] "Basically true" here means it's not strictly true (by
| that I mean it's not true in all possible cases) - but
| classical physics itself is not _strictly_ true, thus
| relativity and QM... which are themselves not _strictly_
| true. We 're still trying to find the theory that accurately
| describes _all_ of physics.
| mensetmanusman wrote:
| When you imagine a red ball, where is that red ball
| physically?
|
| Not the atoms of the neuron configuration etc., but the
| plane of existence where you place the red ball.
| digging wrote:
| I don't understand the question or how it relates to my
| comment, can you elaborate what you mean by "plane of
| existence"?
| mensetmanusman wrote:
| When you imagine from your minds eye, that is a plane of
| some sort.
|
| If we understood exactly where or how this plane exists
| and for whom, we could arbitrarily place objects and
| ideas in this plane. Eg force someone to think of a red
| ball bouncing, or pull imagined objects forcefully out of
| the plane.
| mannykannot wrote:
| Eg force someone to think of a red ball bouncing...
|
| Indeed: put them in a sensory-deprivation tank and show
| them a video of a (possibly simulated) ball bouncing.
| Their existing network of neurons will do the rest.
| digging wrote:
| You're asking me to define the physical nature of
| thought? Of subjective experience? I can't. No one can.
|
| As I already said, though, that doesn't mean we should
| assume there's something metaphysical going on. When I
| think of a red ball neurons fire. We have no reason to
| believe there is anything else going on because we have
| no evidence one way or the other. The experience of
| thinking of a red ball is _not_ evidence that there 's
| anything supernatural going on.
| mannykannot wrote:
| When my computer simulates a red ball bouncing on the
| floor, where is that red ball physically?
| mensetmanusman wrote:
| that's just binary rgb code that is reminding the mind of
| a red ball :)
| mannykannot wrote:
| Precisely.
| TheOtherHobbes wrote:
| Luckily reality is nothing like this.
|
| Probably.
| aeonik wrote:
| There's a good documentary called "The Secret Life of Chaos"
| that has a fairly cool overview of this concept.
|
| Though it's just the beginning of a very deep rabbit hole,
| possibly unending.
|
| Here is a link: https://www.dailymotion.com/video/xv1j0n
| ewhanley wrote:
| There's also a decent (not documentary) limited series that
| explores the idea of determinism. It's pretty good and may be
| of interest. https://en.wikipedia.org/wiki/Devs_(TV_series)
| gpderetta wrote:
| If the path of the marbles were to be determined by some sort
| of gate in the path that would open or close depending, via a
| Geiger detector, on whether some uranium atom had decayed,
| then, as far as we know, the path would be truly unpredictable.
| taeric wrote:
| My mental model for this is to consider boiling water in a
| pot. You can make easy statements over how long it will take
| for all of the water to evaporate. It is, to my
| understanding, impossible to discuss any particular molecule
| or atom.
|
| That is to say, the closer you get to the atomic behavior of
| atoms, the harder it is to make "deterministic" descriptions
| of what is going to happen.
|
| We often describe this in terms of "coin flips" as you can
| make a decent discussion over what you will see on 1000 coin
| flips, but you cannot make such a statement over what you
| will see over 1.
| pants2 wrote:
| You can create a marble run and have marbles more or less
| follow the exact same path every time. However, on some scale
| there is an unpredictable nature to things like Brownian motion
| which affect the run in subtle ways. Perhaps you could get
| closer if you could account for the physical properties of
| every particle in the system beforehand, but a some scale these
| interactions are driven by quantum mechanical processes that
| aren't predictable even with perfect information (as far as we
| know).
|
| To look at it another way, the entropy of a system is always
| increasing, so you don't have enough information when the
| marble is at the top of the hill to know the exact outcome when
| it's at the bottom (on a quantum scale, or over a long enough
| period of time).
| mensetmanusman wrote:
| They would be the same until some number of zeros, past which,
| Heisenberg uncertainty takes over and you cannot predict.
| elromulous wrote:
| This does make me wonder: how do we know that random quantum
| processes are truly random?
|
| This gets philosophical very quickly. But for our purposes:
| independent, uniform, etc. But how do we know there isn't another
| (earlier) way to observe the result in some fashion.
| variadix wrote:
| I think Bell's inequality implies the state can't be
| deterministic but hidden. I'm not sure how you could evaluate
| the "quality" of the randomness, or if there are existing
| results analyzing this.
| nyssos wrote:
| We don't. What we know is that we can't have all of
| 1. locality (no backwards causation / FTL information transfer)
| 2. determinism 3. counterfactual definiteness
| (unperformed measurements still have single definite results:
| we can talk meaningfully about what we would have seen had we
| done a different experiment) 4. QM gives correct
| predictions.
|
| Objective-collapse interpretations (like the version of
| Copenhagen described in introductory textbooks) reject 2:
| collapse is fundamentally indeterministic.
|
| Everett (the badly misnamed "many-worlds" interpretation)
| rejects 3: "measurement" is just what unitary evolution looks
| like from the inside, and from that perspective always has
| multiple outcomes.
|
| Superdeterminism rejects 4: QM is wrong, but the initial
| conditions of the universe were for some reason set up in such
| a way as to prevent us from carrying out any experiments that
| would demonstrate that.
| cb321 wrote:
| Bricmont does a good job of discussing entropy, arrow-of-
| time, and irreversibility, information and probability in a
| purely classical statistical mechanics setting in
| https://arxiv.org/abs/chao-dyn/9603009 .
|
| Bricmont has continued to write/expound upon these ideas ever
| since and more recently "come out" as a non-local hidden
| variables proponent of the de Broglie/Bohm variety which
| rejects your (1. locality) for which you left out an example.
| :-)
|
| Sometimes people refer to giving up "locality" in this
| context with the mouthful "a preferred _fundamental_
| foliation of spacetime ". { "fundamental" here does the work
| to block the Cosmic Microwave Background / "average rest
| frame" which people have no trouble treating as a preferred
| inertial reference frame that is "merely contingent" not
| "fundamental", although Ernst Mach might have begged to
| differ, but that is further afield. :-) }
| throwawaymaths wrote:
| Correct me if I'm wrong, but I don't think we even know what
| "collapse" is. Maybe a better way to say it is that arguments
| about what is collapse are at the root of distinguishing
| interpretations
| nyssos wrote:
| Collapse is when you go from a generic quantum state to an
| eigenstate of a given measurement operator. The
| disagreement is about whether this is an objective feature
| of reality, an artifact of semiclassical approximation, or
| not a real physical process at all.
| throwawaymaths wrote:
| Yeah of course we know what the math is and it
| corresponds to observation, I just mean we don't know
| deeply what it is beyond what we've operationally defined
| it as.
| karmakaze wrote:
| My bet is on 1. backwards causation. Light takes the shortest
| path, by (virtually) taking all of them.
|
| Similarly all paths to the future are taken and the present
| _must_ agree with boundary conditions in the future.
| nyssos wrote:
| > the present must agree with boundary conditions in the
| future.
|
| This is true but it's not really what's meant by backwards
| causation here. The specific thing you need is for what
| happens from times (-e, e) to depend on what will happen at
| times (1-e, 1+e) even after conditioning on the intervening
| times (e, 1-e).
|
| Action principles are still local: maximizing the integral
| of the Lagrangian L(x(t)) over time (by, for instance,
| taking the shortest path) is equivalent to satisfying dL/dx
| = d/dt dL/d(dx/dt).
|
| > by (virtually) taking all of them.
|
| This is a superficially appealing analogy but very
| misleading. Even if you take Feynman diagrams literally,
| which you shouldn't, the "path" integral runs over _field
| configurations_. The classical notion of a particle
| following some path simply breaks down here.
| DebtDeflation wrote:
| I think, ultimately, there are only 3 possible explanations for
| the paradoxes of the quantum world. 1) superdeterminism
| (everything including our choices in quantum experiments today
| were fully determined at the instant of the Big Bang), 2)
| something "outside" our observable reality acting as a global
| hidden variable (whether something like the bulk in brane
| cosmology or whatever is running the simulation in simulation
| theory) or 3) emergent spacetime (if space and time are emergent
| phenomena then locality and causation are not fundamental).
| digging wrote:
| Actually, how are 1 and 2 different? If 2 simply refers to
| another layer of reality, don't we still have to figure out if
| it's deterministic or not? I suppose if it has its own
| completely different (or slightly different[1]) physics, we'd
| be starting over, but we'd still work our way back to the
| question of top-level determinism eventually).
|
| [1] Referring to cosmological natural selection as a theory of
| the "fine-tuned" universe:
| https://en.wikipedia.org/wiki/Cosmological_natural_selection (a
| fun favorite of mine but not looking likely)
| hermannj314 wrote:
| It's simulations all the way down.
| DebtDeflation wrote:
| Fair point. I'm assuming that additional layer of reality is
| deterministic.
| Filligree wrote:
| Many-Worlds? Or does that fall under #2 for you?
| coderenegade wrote:
| Many worlds is really just another form of determinism. If
| everything that can happen does, no one in any of the
| individual universes has free will.
| numinos1 wrote:
| Unless awareness is independent of the universe and
| traverses the branching worlds through observation and free
| will.
| TheOtherHobbes wrote:
| Superdeterminism on its own doesn't explain why quantum
| phenomena are statistical, not deterministic.
|
| It seems strange that a superdeterministic universe constrains
| certain kinds of phenomena to statistical distributions for no
| obvious reason.
|
| Free choice is a completely different issue, and I'm not even
| sure it requires quantum theory. Clearly we have the illusion
| of free choice, but just as obviously our choices are very
| heavily constrained. In fact the constraints pretty much
| determine personality. And there's plenty of evidence from
| psychology that if you you have an accurate model of
| personality you can manipulate someone's choices without them
| being aware of it.
|
| So I'm not seeing what quantum theory adds to this. It seems to
| assume consciousness is quantum and works back from there.
| Which is a weak argument (IMO).
| __turbobrew__ wrote:
| I have yet to see a subscriber of superdeterminism not look both
| ways before crossing the road.
| digging wrote:
| A good quip, lol. But of course they would, because they must,
| because the feeling of control (that is: the unconscious
| _belief_ in control) is just as intrinsic as the actual absence
| of control.
| voxl wrote:
| which in other words makes superdeterminism unfalsifiable,
| because any attempt to do so can be met with "it must have
| been that way"
| digging wrote:
| Absolutely. I find it an interesting thought experiment and
| nothing more unless and until we determine some way to
| actually see through the veil and identify these extra-
| universal hidden variables. (At which point our conception
| of the universe may expand to include these variables and
| whatever else exists in that outer layer.)
| throwawaymaths wrote:
| Of course every other QM interpretation is _also_
| unfalsifiable, e.g. Copenhagen (we have no definition of
| what constitutes an observation) or many-worlds (obviously
| unfalsifiable save for actually tunneling through into
| another universe and coming back to tell the tale)
| Pet_Ant wrote:
| Don't know why this was downvoted. Superdetermination is
| indeed unfalsifiable, because the "super" part means that
| there does not exist anything that has been not determined,
| including our thoughts, this comment and someone rolling
| their eyes reading this.
|
| Being unfalsifiable doesn't mean it's not true, just that
| it isn't a scientific theory.
| mensetmanusman wrote:
| That's why Sam Harris still uses his will to speak to
| various crowds that he has no will.
| karmakaze wrote:
| Or rather they must, because it was determined that they do.
|
| And I'm sure sometimes, some of them _don 't_ look both ways
| for the same reason.
| qarl wrote:
| That's because superdeterminism doesn't imply you shouldn't.
|
| Superdeterminism implies that you don't really have a choice as
| to whether you look both ways.
| jeswin wrote:
| The subscriber has no free will. The question would be - why
| exist?
| sheepdestroyer wrote:
| If true, superdeterminism would not permit them to make that
| choice to look around or not anyway.
| PheonixPharts wrote:
| Does believing that gravity exists mean a person will not roll
| down a hill?
|
| Why would belief that we are just agents responding predictably
| to stimuli imply that one would _not respond predictably to
| stimuli_?
|
| The fact that ones behavior does not change when one
| acknowledges that all behavior is deterministic and
| predetermined seems evidence in _favor_ not against that
| hypothesis.
| nyssos wrote:
| > Why would belief that we are just agents responding
| predictably to stimuli imply that one would not respond
| predictably to stimuli?
|
| This is determinism, not superdeterminism.
|
| Superdeterminism claims that the state of any system you
| measure is always already correlated with the measurements
| you perform on it: photons emitted a billion years ago encode
| information about where someone is going to choose to point a
| telescope tomorrow. Not because of any interaction between
| the two, but because the initial conditions of the early
| universe just happened to be set up that way.
| simiones wrote:
| Sure, but superdeterminism implies determinism. That is, if
| the world is superdeterministic, it is certainly
| deterministic, so living agents definitely react to stimuli
| in a theoretically predictable manner.
|
| Interestingly, it's actually very hard to define what it
| would mean to believe in determinism, but _not_
| superdeterminism. Ultimately if the universe is
| deterministic, that must mean that everything that happens
| is predictable from the initial conditions of the universe.
| nyssos wrote:
| > Ultimately if the universe is deterministic, that must
| mean that everything that happens is predictable from the
| initial conditions of the universe.
|
| This is still not superdeterminism. The superdeterminist
| claim is a statistical one: your choice of measurement is
| not even approximately conditionally independent of the
| state of the thing you're measuring. Ever. There are
| plenty of deterministic processes that nonetheless wipe
| out most correlations over the long-term: thoroughly
| mixing two fluids will do it. Preserving a strong
| correlation between the future state of your brain and
| the exact luminosity of a star a billion light years away
| at one particular moment, over the whole history of the
| universe is _incomprehensibly_ unlikely. And
| superdeterminists claim that this happens every single
| time.
| PheonixPharts wrote:
| "Random" is a property of your mind, not of the world.
|
| If I shuffle a deck of cards in a way that you don't know about,
| then the next card I pull is "random" _to you_ even though,
| obviously, if one were to turn the cards face up nothing would
| have changed about the order of the cards, but now the next card
| would be fully deterministic.
|
| I could likewise sort the deck with an algorithm completely
| unknown to you. I could _perfectly_ predict the next card pulled
| because I know the algorithm, and yet the next card would still
| be random for you.
|
| Heisenberg uncertainty principle is more a statement about the
| limits of knowledge than about "God throwing dice". Randomness
| often has a supernatural property in the popular mind, but is
| really just a statement about how much information we have about
| an event.
|
| The famous Bayesian philosopher ET Jaynes refereed to this
| tendency to confuse the randomness as a property of the world
| rather than our mind as the "Mind Projection Fallacy" [0]
|
| 0. https://en.wikipedia.org/wiki/Mind_projection_fallacy
| danbruc wrote:
| _" Random" is a property of your mind, not of the world._
|
| Limited information about the initial state is one source of
| randomness but not necessarily the only one. Whether there is
| true randomness in the universe is at very least an open
| question.
| PheonixPharts wrote:
| Can you clarify what "true randomness" means out side of the
| context of human agency and perception?
|
| Can you also give an example where "true randomness" would
| differ from the randomness I describe on the actions a human
| would take? That is to say, if a my internal model of the
| world tells me a coin landing on heads is 50/50 how does
| "true randomness" or not of the resulting coin toss impact
| how I should gamble on coin tosses?
|
| imho the idea of "randomness" separate from our own internal
| state of belief is a nonsensical concept, but would
| appreciate examples to the contrary.
| danbruc wrote:
| You can not predict the future state from the current
| state, not even in principle.
|
| Measure the spin of an electron along two different axis,
| to the best of our knowledge - or maybe just my - the
| result of the second measurement is not predictable by
| anything. Of course only until it turns out that hidden
| variables is the correct interpretation and that the hidden
| variables can be measured, then this also becomes the other
| kind of randomness.
| digging wrote:
| In basic interpretations of quantum events, quantum
| properties are _not defined_ until measured. It 's not just
| that we can't see the other side of the card; the card is
| blank until we flip it.
| EA-3167 wrote:
| > Can you clarify what "true randomness" means out side of
| the context of human agency and perception?
|
| Depending on your Interpretation of QM, randomness is a
| fundamental aspect of reality. How does a quantum
| superposition of two states resolve? The canonical view is
| wavefunction collapse, which is ultimately random, and
| attempts to find some pattern underneath it all generally
| fail. Look at the Bell Inequalities, which demonstrate that
| any theory which attempts to reproduce the successful
| predictions has to either be non-local, or non-realistic,
| and must be incompatible with local hidden variables.
|
| Now does that mean nature is random? I don't know, no one
| does, because we're sure that QM isn't a complete theory.
| It is a _really_ good theory though, in some domains such
| as QED it 's been tested to more than 11 decimal places and
| found to hold. The difficulty of making a new theory that
| matches that precision _and_ represents a paradigm shift
| can 't be overstated. The result is that a lot of time is
| spent on those aforementioned Interpretations, you've
| probably heard of some, such as "The Many Worlds
| Interpretation" aka parallel universes. After all if
| _everything_ happens, and we just happen to only perceive a
| part of it, then there is no randomness... no hidden
| variable. When a quantum state collapses, part of it doesn
| 't just vanish, it's just out of our site.
|
| The problem with that is... there's no evidence to support
| it, probably no way to even test it. Anyway, the bottom
| line is that maybe there is _real_ randomness, and maybe
| there isn 't, we just don't know.
| Guvante wrote:
| Do you count wave particle duality as randomness?
|
| Certainly the dual slit experiment makes hidden variables
| very hard to preserve.
|
| Additionally several tests have shown that hidden variables
| don't work to explain quantum mechanics, there aren't
| possible coins the allow the kind of probabilities we see.
| simiones wrote:
| > Can you also give an example where "true randomness"
| would differ from the randomness I describe on the actions
| a human would take? That is to say, if a my internal model
| of the world tells me a coin landing on heads is 50/50 how
| does "true randomness" or not of the resulting coin toss
| impact how I should gamble on coin tosses?
|
| It's pretty simple. If the world is fundamentally
| deterministic, then you should only gamble with someone who
| you believe doesn't possess knowledge you don't. If an
| advanced alien or an angel offers to call a coin toss, you
| shouldn't take their bet, since they might know how to
| determine the result of the coin toss based on the weather
| and the color of the coin tosser's pants.
|
| On the other hand, if the universe is fundamentally random
| at every turn, then you can safely take the bet: nothing
| they know could give them more information than you have
| about the result of the coin toss.
|
| This is very similar to the difference between pseudo-
| random number generators (PRNGs) and sources of true
| randomness in a computer. There is no test you could do on
| the outputs of an RNG to determine if it is a (good,
| cryptographic-grade) PRNG or if it is a "true" RNG.
| However, if you're gambling based on the results of a PRNG,
| you should try to find out if the one you're gambling
| against doesn't happen to know the seed (in which case they
| can predict with 100% certainty what the next number will
| be).
| losvedir wrote:
| I'm not an expert, but I think the "orthodox" understanding is
| that quantum mechanics is fundamentally rooted in probabilities
| at the lowest level. The position you're taking, that quantum
| uncertainty isn't inherent in the system, but just related to
| us not knowing enough about it, is considered a "hidden
| variables" hypothesis.
|
| And I think those have been ruled out by Bell's Theorem, or at
| least implies other very counterintuitive things have to be
| true instead.
| phkahler wrote:
| >> And I think those have been ruled out by Bell's Theorem,
| or at least implies other very counterintuitive things have
| to be true instead.
|
| Non locality seems less weird to me than any of the other
| interpretations of quantum mechanics. But I feel like I'm in
| a small minority with this. Besides, what we think about it
| isn't really relevant.
| digging wrote:
| Not sure I agree fully in the case of Uncertainty. To the best
| of our knowledge, an undetermined quantum property is
| _actually_ undefined. Whether we go with the simple Many Worlds
| or the Copenhagen wave function collapse or even Pilot Wave
| theory, when the value becomes defined it is randomly selected
| (or our World is a random selection of all of them) according
| to the wave function.
|
| I believe what you're saying is that there is indeed a
| superdeterministic hidden variable that would allow us to know
| before the value is defined what it will be. For simplicity
| let's assume the Many Worlds interpretation... this variable
| would tell us _which_ world we 're in.
|
| The issue with this explanation is that we're not in that World
| yet, because our current World is only the result of _past_
| quantum events. When this next undefined value becomes defined,
| our single world splits into Many more Worlds, each of which
| has ours as a parent, so how could one of those be more or less
| intrinsically ours? Each is equally our World, and if we back
| up a single "step", our World contains _all_ of the supposed
| hidden variables that say which child World is which. So I find
| that Many Worlds seems to invalidate superdeterministic hidden
| variables.
|
| With other, single-World interpretations, the hidden variables
| make more sense. What you say would be true. But single-World
| interpretations are already more complicated than Many Worlds,
| with or without hidden variables and superdeterminism.
| simiones wrote:
| I don't think you're right about the many worlds
| interpretation here.
|
| In the most popular "simple" many worlds interpretation, the
| whole universe is a QM system described by the universal
| wavefunction. The "worlds" are just "branches" of the
| wavefunction that are not entangled with one another.
|
| The Schrodinger equation (and the more advanced QFT versions)
| are fully deterministic differential equations: the state of
| the universe at time T is fully determined by the state of
| the universe at time T-x, for any x. This remains true even
| if x is negative: there is no "arrow of time" in QM, there is
| no distinction between the past and the future in any QM
| equations.
|
| The only "non-determinism" in Many Worlds is thus of the
| knowledge kind: you don't know which "world" you happen to be
| in, so you don't know which result you'll notice. But this is
| like being spun around a coin: you don't know which face
| you'll end up looking at, but you know both faces actually
| exist. All the possible outcomes of any QM event are realized
| in "some world", there is 0 uncertainty.
| digging wrote:
| Hm, that could be correct actually. Perhaps Many Worlds is
| the most deterministic interpretation and I've got it
| backward - this clearly is not my day job :)
| Jensson wrote:
| > Heisenberg uncertainty principle is more a statement about
| the limits of knowledge than about "God throwing dice".
|
| This isn't what physicists believe though, Heisenberg
| uncertainty principle is about a wave not having both a well
| defined position and velocity. They either drift apart
| (undefined velocity) or they are spread apart (undefined
| position). Then the wave collapse keeps the wave together over
| time by randomly removing parts of it, we have no theory where
| that isn't random even "many world" means you randomly select
| one of the branches to follow.
|
| We do know for sure that particles are waves that spread out
| and exist in all of those parts, it isn't just that it
| represent a point particle with unknown location. And we know
| for sure that those waves under certain circumstances withdraw
| from parts and just keep other parts, ie wave collapses. Both
| of those are easily observed in experiments and not up for
| debate.
| simiones wrote:
| If QM is correct and there is no "deeper" hidden variable
| theory that explains the movement of all particles, then you're
| wrong.
|
| Heisenberg uncertainty as it exists in QM today is not a
| statement about your knowledge, it is a statement about the
| possible interactions between particles. It tells you that if a
| particle collides with another at a specific point in space,
| then their trajectories after that collision can't depend on
| the momentum of either particle, for example, because that
| would violate the inequality.
|
| This indeed does not necessarily imply randomness per se. But
| it is much more than a statement about precision of
| measurements at a human scale: it is a statement about the
| possible interactions at even the lowest scales.
| Lichtso wrote:
| The uncertainty principle is just a really misunderstood
| concept because it was first discovered in the context of
| quantum physics (Heisenberg 1927) and only later (Gabor 1946)
| the underlying mathematical principle that causes it was
| discovered.
|
| It has nothing to do with measurement, knowledge, randomness or
| even our physical reality at all. It is a much more fundamental
| mathematical phenomenon [0] that always occurs when you switch
| representation between time and frequency domains and it tells
| you how you can arrange information in such mixed
| representations.
|
| [0]:
| https://en.wikipedia.org/wiki/Uncertainty_principle#Signal_p...
| munch117 wrote:
| Appealing to quantum theory to defend free will does not make
| sense.
|
| If the quantum randomness is fundamental, and reality is
| stochastic at heart, that makes it non-deterministic, but it
| doesn't make it any less mechanical. It's in the name, after all:
| Quantum _mechanics_. If there is any guiding light to the
| randomness, any pattern to how the random choices come out, then
| it 's not really random, is it?
|
| So, if you think that a deterministic reality is devoid of free
| will, then you must equally think that a Copenhagen-
| interpretation fundamentally stochastic reality is devoid of free
| will.
| nwiswell wrote:
| > If there is any guiding light to the randomness, any pattern
| to how the random choices come out, then it's not really
| random, is it?
|
| Well, yeah, that's the point. By definition, a deterministic
| model of reality means there is no room for a free agent to
| make decisions: things couldn't have worked out another way.
|
| But a mechanism that _appears random_ provides at least the
| potential for a free agent, since randomness is exactly what it
| looks like when you cannot predict system outputs purely from
| system inputs.
|
| It's really a semantic issue. It's not that it's a source of
| _randomness_ that we 're after in order for free will to be
| possible, but rather _non-causality,_ and quantum mechanics
| does provide some potential in that regard.
| dotsam wrote:
| I find the idea of computational irreducibility useful for
| rescuing a type of free will in a fully determined world.
| Computationally irreducible programs are perfectly
| deterministic, yet you can't predict the output before you
| run them, and nor are there any shortcuts to get there before
| running them for the first time. The program running in our
| brains for 'free will' can be computationally irreducible in
| this way. No-one can say with perfect accuracy what we will
| choose to do in advance, not even us.
|
| For me, this kind of free will is enough, though it is rather
| deflationary when compared to some kind of godlike non-causal
| free will. I think that if we search for non-causal free
| will, we lose any hope of explanation or understanding:
| presumably if it's non-causal, then anything can happen, for
| no reason.
| tromp wrote:
| > All the observed complexities can be regarded as partial
| descriptions of a simple fundamental reality: the Universe's
| wavefunction. As an analogy, a perfect sphere can be cut into
| many chunks with complicated shapes, yet they can be put back
| together to form a simple sphere.
|
| As another analogy, the 100-bit lambda calculus term
|
| (l 1 1) (l (l l l 1 (2 (l l l 3 1 (2 (l 2)))) (3 (l 4 (l 4 (2
| 1))))) (1 1)) (l 1)
|
| is a binary tree containing all (infinitely many) closed lambda
| terms at its leaves. Thus including representations of all
| possible data and all programs.
| ericfrazier wrote:
| Proving the world operates without free will is trivial.
| mensetmanusman wrote:
| Just die and see?
| MrGinkgo wrote:
| Not sure if this is just a moot point, but I'll say it because
| I'm genuinely curious to hear what people have to say. Anytime I
| hear theories like this, I feel wary of accepting it as an air-
| tight reliable outlook because of human limitations. Like, our
| understanding of quantum physics and all natural laws come from
| what we can percieve and measure, but there's bound to be
| phenomena which we can't percieve or measure (either yet, or
| ever) which limit our understanding of the universe. I understand
| that science is a constant process, and that we shouldn't jump to
| conclusions of any theories being "truth" because of this
| process, but anytime anything like this comes up, I'm always wary
| of the consequences that occur from all the people who DO
| dogmatically assert that it's undeniable, especially with how
| easily theories of predeterminism tend to enable unproductive,
| nihilistic outlooks. I don't necessarily see science as trivial
| pursuit because of our human limitations, but I feel like not
| enough people have learned their lesson about the consequences of
| eagerly accepting a "work in progress" as "ultimate truth".
| moritzwarhier wrote:
| Very well put!
|
| > I don't necessarily see science as trivial pursuit because of
| our human limitations
|
| Me neither, quite the opposite, but the problem you are
| describing has always been a problem when discussing
| metaphysics, as it is commonly called.
|
| Science is aware of its limitations, that's what makes it
| science.
|
| But sometimes, people tend to conflate a materialistic world
| view (maybe even strong determinism) with believing in the
| scientific method.
|
| The "belief" I mean here is strongly tied to assigning the
| appropriate role in ones thinking to scientific facts.
|
| Proving an all-encompassing scientific world view is a logical
| paradox.
| broscillator wrote:
| > But sometimes, people tend to conflate a materialistic
| world view (maybe even strong determinism) with believing in
| the scientific method.
|
| I would say more than sometimes. It seems that if you're not
| like that, you're immediately labeled religious.
| thefaux wrote:
| Religious is also a modern pejorative. It's pretty silly
| the way it's used given that extreme atheism is just as
| dogmatic as so called religious faith.
| dotsam wrote:
| Scientific knowledge, like all knowledge, is fallible. All we
| can hope to do is correct errors and generate better
| explanations.
|
| There is no "ultimate truth" or airtight reliable outlook at
| which we can stop and say we know everything there is to know
| -- that would be a dogmatic assertion, and it is false.
| broscillator wrote:
| I think you're just describing human nature. We can look back
| and see how incomplete theories about the world led to horrible
| acts, or to averting our eyes from those acts because we
| thought it was justified, or because we thought there was no
| better way, or out of fear.
|
| Yet there's the prevalent sense of "this time we're getting it
| right".
| pmontra wrote:
| People did horrible acts because they did want to do those
| acts to those other people. They picked a theory to justify
| them.
| at_a_remove wrote:
| I've never seen some consensus as to the definition of free will
| to the extent that it was testable. As in, "What experiment can
| we perform to show this thing has free will?" or "Define free
| will in such a fashion that a universe with free will is notably
| and different from a universe _without_ free will, in a manner we
| can detect. "
|
| If we cannot do that, I am not even sure what the point is of
| discussing the concept. It is like some box we are told lies
| sealed in a distant continent, and we argue about what is in the
| box. Why? We'll never know, and the answer doesn't seem to change
| anything.
| karaterobot wrote:
| I have not heard a convincing explanation of how the universe
| could produce the Monorail episode of _The Simpsons_ merely by a
| certain configuration of energies in the first moment of the big
| bang, and the consequences of thereof. The most obvious argument
| is that the Monorail episode of _The Simpsons_ is not only
| possible in at least one of the infinitude of quantum,
| deterministic universes, but inevitable, and that the seeming
| absurdity is merely my inability to acknowledge my anthropic
| bias. Nonetheless, I laugh every time I think about the motion of
| particles leading unavoidably to the invention of everything
| required for someone to type "I call the big one Bitey!", and
| for me to appreciate it--or believe, as I must--that I appreciate
| it. The mind reels!
| twiceaday wrote:
| The three body problem is impossible to solve analytically. The
| state space is clearly all connected but in a way that cannot
| be short-cut. You have to walk it deterministically one state
| at a time. Once you reach some interesting state, you know that
| you will always reach it from your initial state. It is
| inevitable but in general impossible to predict. There is no
| simple story to tell as to why you'd end up there, you just do
| as a culmination of the state-path up to that state. We've
| reached a state where that Simpsons episode was created. It's
| very interesting and was impossible to predict from all the way
| back during the bing bang. Maybe it was inevitable?
| aap_ wrote:
| The cosmic ballet goes on.
| Xcelerate wrote:
| I feel like "deterministic" and "predictable" are often
| conflated. Suppose I give you the output of encoding a secret
| message with a one-time pad. Can you predict the message contents
| without the one-time pad? No. Does that mean the output was
| generated non-deterministically? No.
|
| More generally, there are strings with Kolmogorov complexity of
| at least the length of the string but for which the conditional
| Kolmogorov complexity is very small given some other string.
|
| In this sense, it's quite possible that quantum mechanics is
| fully deterministic _and_ there is a hard limit on our ability to
| predict the future (so for all intents and purposes, quantum
| mechanics is at some level indistinguishable from true randomness
| _to us_ despite there being no randomness whatsoever in the laws
| of physics). In fact, I think the former actually implies the
| latter:
|
| Consider a completely classical, deterministic universe (or at
| least imagine a high fidelity molecular dynamics simulation of
| our lightcone of the universe). Then all of the actions that
| humans take in an attempt to predict future observations are
| fully pre-ordained. Why should it be the case that these actions
| just so happen to lead to output that describes another
| subsystem's behavior to arbitrary precision? That would be a
| strange coincidence to have for whatever set of laws describes
| the time evolution of this hypothetical universe. Mathematically,
| how many universes like that are even possible? What sort of
| bizarre initial conditions would there have to be for this to be
| the case?
|
| My take is pretty simple: 1) the universe is fully deterministic
| and 2) quantum mechanics appears inherently random _to us_
| because we are inescapably part of the system we are trying to
| study and predict.
|
| So now the interesting question: is there is an experiment that
| can distinguish between the case of a fully deterministic
| universe and one with non-deterministic processes, given that the
| two would seem to appear the same as far as human observation is
| concerned?
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