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Entanglement Could Be a Deterministic Phenomenon

kdawson posted more than 4 years ago | from the playing-dice dept.

Science 259

KentuckyFC writes "Nobel prize-winning physicist Gerard 't Hooft has joined the likes of computer scientists Stephen Wolfram and Ed Fredkin in claiming that the universe can be accurately modeled by cellular automata. The novel aspect of 't Hooft's model is that it allows quantum mechanics and, in particular, the spooky action at a distance known as entanglement to be deterministic. The idea that quantum mechanics is fundamentally deterministic is known as hidden variable theory but has been widely discounted by physicists because numerous experiments have shown its predictions to be wrong. But 't Hooft says his cellular automaton model is a new class of hidden variable theory that falls outside the remit of previous tests. However, he readily admits that the new model has serious shortcomings — it lacks some of the basic symmetries that our universe enjoys, such as rotational symmetry. However, 't Hooft adds that he is working on modifications that will make the model more realistic (abstract)."

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259 comments

Arm the laser banks ! (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#29231179)

We are going in for the first deterministic first post.

I knew it. (5, Funny)

Anonymous Coward | more than 4 years ago | (#29231189)

Free will is a sham. Of course, believe whatever you will. It's not like you have a choice.

Re:I knew it. (1, Insightful)

tecnico.hitos (1490201) | more than 4 years ago | (#29231623)

Oh, but everyone have free will. It's just the decision you will make is determined by your biology, experiences and environment.

It doesn't mean you don't make a decision.

Re:I knew it. (2, Insightful)

Impy the Impiuos Imp (442658) | more than 4 years ago | (#29231779)

That's where the philosophy chokes. It assumes making a decision, i.e. weighing pros and cons and your emotions and information, is somehow magically free of both determinism and random control. They may have influence, but ultimately there's some mysterious spiritual thing beyond determinism and randomness that's doing the deciding in a manner that doesn't involve either.

Which, I submit, makes no sense. Weighing options is the essence of determinism, for that matter.

More importantly, back to the physics, you can easily base quantum on determinism if you give up on Einstein's concept of reality. Which is to say, that there are "real things out there with real, measurable properties".

Quantum implies heavily that, for example, there is no particle out there with an actual, measurable position, and so on.

But if Quantum Mechanics itself was, say, a computer simulation, then the whole hidden-variables problem disappears as an issue. I.e. the "wavicles" of QM and their quantum properties don't even exist as real objects. The "probability cloud" and entanglement are not real features. Of course, that really violates Einstein's sacred belief about real objects out there.

Re:I knew it. (1)

spazdor (902907) | more than 4 years ago | (#29232589)

you can easily base quantum on determinism if you give up on Einstein's concept of reality. Which is to say, that there are "real things out there with real, measurable properties".

Quantum implies heavily that, for example, there is no particle out there with an actual, measurable position, and so on.

You needn't give up on Einstein's notion just to believe in QM. There are still real things out there, with real, measurable, probabilistic properties. There's nothing more 'real' about a Bohr atom than a Planck one.

Re:I knew it. (3, Insightful)

John Hasler (414242) | more than 4 years ago | (#29232693)

> But if Quantum Mechanics itself was, say, a computer simulation... ...then the computer on which the simulation is running must exist in a universe. You now have replaced a few hidden variables with an entire hidden universe. Apply Occam's Razor.

Re:I knew it. (1)

holmstar (1388267) | more than 4 years ago | (#29233137)

Occam's Razor is just a rule of thumb. It doesn't prove that the simpler answer is the correct one.

Re:I knew it. (1)

Torodung (31985) | more than 4 years ago | (#29233299)

In fact, I'd say that Occam's Razor is a tautology. What it really says is that a simpler solution/explanation is more easily implemented/grasped. More useful and productive.

No matter how complex things actually are, it's nothing but art appreciation if you can't wrap your head around the idea, understand, and produce something with that understanding.

That is the essence of Occam's Razor.

--
Toro

Re:I knew it. (1, Interesting)

Anonymous Coward | more than 4 years ago | (#29232825)

That's where the philosophy chokes. It assumes making a decision, i.e. weighing pros and cons and your emotions and information, is somehow magically free of both determinism and random control. They may have influence, but ultimately there's some mysterious spiritual thing beyond determinism and randomness that's doing the deciding in a manner that doesn't involve either.

The mind may or may not have a spritual (in the supernatural sense of the word) aspect, but that is beside the point. The mind could very well be an emergent phenomena that involves a combination of both deterministic and random features which are the result of purely natural features. In that case the mind is neither purely deterministic nor random, rather the mind is both simultaneously!

Which, I submit, makes no sense. Weighing options is the essence of determinism, for that matter.

Weighing options is also the essence of Free Will. There is also more than one [wikipedia.org] philsophical formulation of Determinism [wikipedia.org]. While various Incompatibilist stances seems most prevalent on Slashdot (and with IT professionals in general), it has no more empericial evidence than any of the Compatibilist stances. The former essentially believes that of all theoretical options only one (the one selected by the agent) was possible based on all circustances surrounding a given decision, basically reducing every decision to a huge conditional function (which might partially explain why IT proefessionials tend to prefer it:P). The latter believes that while the circustances surrounding the decision may heavily influence what the agent chooses, they are still free to choose one of multiple options and which one they choose can't always be predicted regardless if the prediction has complete and perfect information about both the circumstances and the agent involved in the choice.

I haven't studied the parts of Physics involved enough to meaningfully comment on the second half of your post.

Re:I knew it. (1)

huckamania (533052) | more than 4 years ago | (#29233141)

It assumes making a decision, i.e. weighing pros and cons and your emotions and information, is somehow magically free of both determinism and random control. They may have influence, but ultimately there's some mysterious spiritual thing beyond determinism and randomness that's doing the deciding in a manner that doesn't involve either.

Where does this nonsense come from? If you did something and feel later that there is some mysterious spiritual thing that decided what that something was, seek help before the mysterious spiritual thing has you jumping off a roof. I think using the word 'free' to describe something is a disservice to everyone who follows. Like FOSS, the free in free will is a distraction that will never go away. Is it controversial to say that someone has 'will power'? Why is it a controversy for intelligent animals to have 'free will'?

Quantum implies heavily that, for example, there is no particle out there with an actual, measurable position

Really? From Wikipedia In quantum mechanics, the Heisenberg uncertainty principle states that certain pairs of physical properties, like position and momentum, cannot both be known to arbitrary precision. I guess if the particles were really 'out there' then we couldn't actually measure their position from in here. If they came in here then we might have a chance.

But if Quantum Mechanics itself was, say, a computer simulation, then the whole hidden-variables problem disappears as an issue.

QM is a theory describing the Universe. If QM itself was, say, a computer simulation, then the Universe is a computer simulation, running on God's box (elite gaming rig, of course). Unless the computer running the simulation is a simulation itself. Eventually you'd have to have a real computer in the really real reality, possibly sitting on a stack of turtles.

Re:I knew it. (5, Insightful)

Chris Burke (6130) | more than 4 years ago | (#29231879)

Free will is a sham. Of course, believe whatever you will. It's not like you have a choice.

Dude, if you were counting on the non-determinism of quantum entanglement to save the concept of free will, then you were out on a limb to begin with. How is randomly following the rules of the universe any more a matter of "will" than deterministically following them?

You could try to rely on a seriously weird and unlikely interpretation of QM which is basically a pun (measurement -> observation -> observer -> sentient observer), but then you're using the concept of sentience/free will influencing quantum events to explain how sentience/free will is possible in the first place. Maybe it's possible, but it's quite a long shot to be basing your whole concept of self awareness on.

I have free will because as far as I can tell I exercise it. In a pure philosophical sense you could never prove you have it even if we somehow did show that QM is influenced by "observers". But that act of faith has worked well enough for me. I'm certainly going to live my life as though I have free will, and if I'm only "automatically" making that choice, then so be it.

Its just a matter of modeling (5, Insightful)

Brain-Fu (1274756) | more than 4 years ago | (#29232263)

When you model the universe in terms of will-less mechanisms, you will (amazing!) discover that free will is a logical impossibility.

Trying to model free will in terms of physics is like trying to describe the combustion engine using only the words found in a book on home gardening.

The only reason some people find this personally problematic is because they have decided that our current model of physics is also the concrete, accurately-represented holy truth. In fact, our current model is just an abstract representation of something we can't see, and it is just the best we've come up with so far (in fact, any scientist worth his salt will predict that our models will change in the future).

So the quantum-mechanical model of the universe is incompatible with any free-will-is-real model of the universe. So what? This incompatibility doesn't make either theory right or wrong. The evidence for each theory is all that matters.

As Epicurus [wikipedia.org] (one of the fathers of the modern scientific method) advised, "if several theories are consistent with the observed data, retain them all."

Re:Its just a matter of modeling (1)

Korin43 (881732) | more than 4 years ago | (#29232807)

And how would you model the universe.. In terms of magic?

Ask an alchemist. (4, Insightful)

Anonymous Coward | more than 4 years ago | (#29233089)

Or maybe a Sorceror.
Or maybe a Christian.

Modeling the universe in terms of magic is what humanity has been doing for most of recorded history.

Modeling the universe in terms of mechanical interactions of particles or waves is the new-and-cool. And we are still getting our heads around how to do it.

Re:Its just a matter of modeling (1)

Torodung (31985) | more than 4 years ago | (#29233361)

Why not? Belief systems still function even though we don't understand why or how they work. For most of the population, quantum physics might as well be magic!

I have a particular opinion about which is a better model, but I'm an admittedly lousy "magical thinker." ;^)

--
Toro

Re:Its just a matter of modeling (2, Interesting)

Anonymous Coward | more than 4 years ago | (#29232915)

The current model of the universe is not necessarily composed of will-less mechanisms.

In fact the non-determinism of QM (if it is so) could be exactly the mechanism by which free will is introduced into the universe. QM does not have to be random as insinuated by the GP, but it instead could be the method by which free will forces (perhaps our 'souls') outside the universe (as we see it) inject their free will into the universe (by slight manipulation of the odds so to speak).

I don't believe this myself, but I also don't see why it isn't theoretically possible.

Re:Its just a matter of modeling (2, Interesting)

blackraven14250 (902843) | more than 4 years ago | (#29233457)

That's really insightful, and I'd give you a +1 for it. You're completely right that the introduction of our will could very well be us, without knowing due to barriers beyond science, changing a quantum particle from a superposition into one of it's potential positions. In fact, there's no proof that the essence of a person's mind actually is created on this plane of existence, lending a large amount of potential to this argument.

Re:I knew it. (1)

NickFortune (613926) | more than 4 years ago | (#29232831)

Interesting subject.

You could try to rely on a seriously weird and unlikely interpretation of QM which is basically a pun (measurement -> observation -> observer -> sentient observer), but then you're using the concept of sentience/free will influencing quantum events to explain how sentience/free will is possible in the first place.

Or maybe just pointing out that there's room for free will in the quantum model. I know the idea is unpopular among physicists, but I didn't think anything had emerged that made it significantly less likely than any other interpretation.

There's also a real question of what constitutes "measurement" in the absence of conciousness. You can placing a ruler on a desk to measure a line, but in the absence of intention and perception, there's nothing to distinguish such an occurrence from any other collision between two pieces of wood.

I have free will because as far as I can tell I exercise it.

Good call :) Personally, I think free will and determinism are merely useful models of reality. Determinism works well if you're designing an engine. Free will works better for things on a personal and social level. I suspect neither is entirely true in objective terms.

The trick, of course, is to use the worldview best suited to the task at hand.

Re:I knew it. (0)

Anonymous Coward | more than 4 years ago | (#29233025)

What the fuck

Re:I knew it. (1)

Atario (673917) | more than 4 years ago | (#29233431)

I have free will because as far as I can tell I exercise it.

Or, put another way, you are not capable of perceiving the phenomena that constitute your deterministic behavior ahead of time. This should come as no surprise, since doing so would no doubt interact with that very behavior. Not to mention that we're all caught up in a Sensitive Dependence On Initial Conditions maelstrom on every level imaginable.

I have free will (2, Funny)

kiick (102190) | more than 4 years ago | (#29231947)

...because I choose to believe that I have free will.

If you don't believe in free will, then there's no use arguing with me, because it's been pre-determined that I will believe in free will.

PS:
Isn't trying to change someone's mind pretty much a futile gesture to a determinist?

Re:I have free will (1)

Rockoon (1252108) | more than 4 years ago | (#29232161)

No.

I am a determinist because I believe that everything that ever happened and everything that ever will happen can be explained by particles following one simple rule: The path of least resistance.

The fact is that in following that path, my brain insists on convincing you of my wisdom. It may very well be that in following that path, your brain begins to believe that I am in fact extremely wise.

That this is inevitable, I cannot say.

Re:I have free will (1)

Torodung (31985) | more than 4 years ago | (#29233397)

And the path of least resistance is inevitably entropy. The abyss called, it wants to stare back at you.

Scary to consider, but I think you're dead on.

--
Toro

Re:I have free will (0)

Anonymous Coward | more than 4 years ago | (#29232255)

> Isn't trying to change someone's mind pretty much a futile gesture to a determinist?

Not if you are destined to have your mind changed by somebody destined to try!

Re:I have free will (1)

Code Master (164951) | more than 4 years ago | (#29232363)

Not if the person has been predetermined to change their mind after the attempt. It's not like they have a choice to be changed.

Re:I knew it. (0)

Anonymous Coward | more than 4 years ago | (#29232117)

The mice were right!

Re:I knew it. (2, Funny)

sexconker (1179573) | more than 4 years ago | (#29232135)

It may be, but science has not even attempted to define who I, my conscious self, am.

How does a lump of grey matter result in a singular consciousness?

All you other fuckers, you're just deterministic machines. I could model you perfectly given enough time.

But me? I'm something...else.

Re:I knew it. (1)

JamesP (688957) | more than 4 years ago | (#29232157)

Well, will is nothing more than the output of a huge amount of data fed into a chaotic function.

Re:I knew it. (0)

Anonymous Coward | more than 4 years ago | (#29232447)

Yeah, right. You had to say that.

Hidden controlled by Hidden (4, Insightful)

Twillerror (536681) | more than 4 years ago | (#29231213)

I've often been skeptical of the idea that you could disproove a hidden variable. The hidden variable itself could be dynamic controlled by another hidden variable.

I guess I just assume that there is more we don't know about the universe that we do know about it.

Re:Hidden controlled by Hidden (1, Insightful)

Anonymous Coward | more than 4 years ago | (#29231511)

Whoa who modded this troll? The parent is making a valid point. The line between deterministic and stochastic can sometimes be blurry. Hidden variables don't have to exactly stochastic. A stochastic variable, for instance, can often be approximated by deterministic variables -- you just create multiple scenarios. This is often done in stochastic programming -- certain stochastic programs can be transformed into deterministic form (e.g. multiperiod formulations).

Someone's obviously trigger happy this morning.

Re:Hidden controlled by Hidden (5, Informative)

blueg3 (192743) | more than 4 years ago | (#29231675)

It's not really valid, though; it makes a false distinction between "a hidden variable" and "a hidden variable controlled by another hidden variable" as if they were different. Bell's theorem covers (or at least appears to cover) any additional information or state, regardless of the theory or process involved, provided that state is "attached" to the entangled particles (that is, it's local).

Re:Hidden controlled by Hidden (1)

0xABADC0DA (867955) | more than 4 years ago | (#29232523)

provided that state is "attached" to the entangled particles (that is, it's local).

A hidden variable:

      return self.state;

A hidden variable controlled by another hidden variable:

      self.state = self.last_observed_by->state;
      return self.state;

An entangled variable that isn't known yet:

      self.state = calc_state(self, self.last_observed_by);
      return self.state;

I think these three are very different cases, and afaik (not much) only the first has been ruled out. Just because the second and third may be 'the same' for some particular experiment doesn't mean they are in fact the same. For instance, what happens when "self.last_observed_by.self != self" (ie one particle interacted with something else and the other didn't). Is there no interaction in either direction, or is there a interaction in just one direction, or is there a different kind of interaction?

Re:Hidden controlled by Hidden (3, Informative)

locofungus (179280) | more than 4 years ago | (#29232721)

Bells inequality rules out every possibility of the case:

result_of_experiment = me.some_function();

where some_function() has access to the entire history of me plus as much additional local information as you like (including internal variables) and it is deterministic.

There is a tiny "loophole" in that a truly rigourous test is extremely hard to do and not everybody agrees that the experiments done so far are 100% watertight.

Tim.

Re:Hidden controlled by Hidden (0)

Anonymous Coward | more than 4 years ago | (#29233073)

What I'm getting at is, has there been any research on more than just two particles...

A and B are 'entangled', B interacts with C, how are measurements of A, B, and C related after that?

It seems to me that maybe there can be hidden variables and spooky interaction at a distance.

Re:Hidden controlled by Hidden (0)

Anonymous Coward | more than 4 years ago | (#29233225)

Yep, but the second and third scenarios aren't local because they make a reference to last_observed_by, which might be in a galaxy far far away by the time the reference is made. We already know there are lots of nonlocal models for quantum mechanics.

Re:Hidden controlled by Hidden (1)

vertinox (846076) | more than 4 years ago | (#29232881)

It's not really valid, though; it makes a false distinction between "a hidden variable" and "a hidden variable controlled by another hidden variable" as if they were different.

I can't remember who said this (might have been Hawking or Sir Francis Bacon) was that there is a very important difference between "That which 'I know I don't know' and that which 'I don't know that I don't know'"

Re:Hidden controlled by Hidden (2, Funny)

mfnickster (182520) | more than 4 years ago | (#29232295)

> The hidden variable itself could be dynamic controlled by another hidden variable.

You can't fool me, young man! It's variables ALL the way down! :)

Universe.tar.gz (1, Insightful)

drseuk (824707) | more than 4 years ago | (#29231247)

I'll believe it when it's finished downloading - I may be some time.

Re:Universe.tar.gz (0)

Anonymous Coward | more than 4 years ago | (#29232173)

Yeah, god should have used bz2 or lzma when he made that tarball. What a bozo!

His model is all wrong (2, Funny)

Anonymous Coward | more than 4 years ago | (#29231263)

In his model of the universe, everyone has a beard or goatee.

Re:His model is all wrong (0)

Anonymous Coward | more than 4 years ago | (#29232757)

Troll? Classic Trek reference goes whoosh.

Come up with a generic theory... (1)

nweaver (113078) | more than 4 years ago | (#29231275)

And then tweak it to match reality.

I'm afraid people do that all the time, each one new and different.

But why do they bother? We already have the ultimate "parameterize and tweak the theory to match reality" theory in String Theory, so why bother with anything else?

Re:Come up with a generic theory... (4, Insightful)

Anonymous Coward | more than 4 years ago | (#29231509)

Come up with a generic theory...And then tweak it to match reality.
I'm afraid people do that all the time, each one new and different.

Uh...yeah. That is how the scientific process is supposed to work. You form a hypothesis based on what you know already, you test it, and as the results of your tests roll in, you modify the hypothesis accordingly. Form and then tweak. This is the essence of all scientific progress we have made to date.

Why do you have a problem with this? I'd say the proof is in the pudding.

But why do they bother? We already have the ultimate "parameterize and tweak the theory to match reality" theory in String Theory, so why bother with anything else?

Because string theory lacks evidence, and we don't have the technological means to gather much evidence for it (at present). Also, at present, the theory fails to offer much utility (we can't build any useful devices based on string theory).

Your attitude sounds a bit scarey. I read it as, "we already KNOW the truth, so why continue looking?" This very attitude inhibited scientific progress for most of human history. I wonder if it also inhibits you?

Re:Come up with a generic theory... (1)

firewrought (36952) | more than 4 years ago | (#29232469)

Come up with a generic theory...And then tweak it to match reality. I'm afraid people do that all the time, each one new and different.

That is how the scientific process is supposed to work. You form a hypothesis based on what you know already, you test it, and as the results of your tests roll in, you modify the hypothesis accordingly. Form and then tweak. This is the essence of all scientific progress we have made to date. Why do you have a problem with this?

I think you misunderstood the parent's use of generic. When you can tweak the parameters of a theory to match any possible outcome, your theory no longer has any predictive power. For instance, there is a number--a universal constant if you will--that you can add to this post to reveal who killed JFK. This post, therefore, is a "theory" with only one parameter, but since we can find parameters describing all possible suspects, it's sort of a truism in disguise.

The parent was referencing string theory as an example of something that has become too broad... he wasn't endorsing it.

Re:Come up with a generic theory... (1)

blueg3 (192743) | more than 4 years ago | (#29231591)

This argument only seems relevant if your generic theory is completely generic; that is, with the proper choice of parameters, it can be exactly equal to any alternative theory. This is true neither of string theory nor physics-as-cellular-automata.

Re:Come up with a generic theory... (1)

Captain Spam (66120) | more than 4 years ago | (#29231679)

This argument only seems relevant if your generic theory is completely generic;

"Things happen. Sometimes."

I think that about wraps up everything.

"Backwards" Causation (5, Interesting)

etymxris (121288) | more than 4 years ago | (#29231353)

Bell's inequalities fall apart if current particles can "know" about future measuring devices. However, for particle physics, neither direction of time is privileged. Particles are just as likely to be influenced by future interactions as they are by past interactions. Because of this, there is no "action at a distance". Influences travel along the backwards light cone and remain perfectly relativistic.

This simple, straightforward solution has been largely ignored.

Note that most interpretations of quantum mechanics are explicitly time asymmetric due to the "collapse" caused by observation. Cramer's transactional theory is an exception, it is symmetric and there is no collapse, but it doesn't get much attention.

Re:"Backwards" Causation (1, Funny)

Anonymous Coward | more than 4 years ago | (#29231621)

I have no idea what any of that means but I am so going to memorize it for the next time I need to have a fake cell phone conversation in public!

Re:"Backwards" Causation (1, Insightful)

Anonymous Coward | more than 4 years ago | (#29231841)

Given that Bell's inequality has been violated routinely in experiments any theory is going to have to give up on either local realism or causality. Is it really surprising that it's easier to toss out local realism? Personally I find it a lot easier to give up on locality than causality. Is a theory that rejects causality really straightforward?

Re:"Backwards" Causation (2, Informative)

etymxris (121288) | more than 4 years ago | (#29231981)

If "causality" as you use it is explicitly asymmetric, then yes, it's fairly straightforward to reject it. Typical arguments against backwards causation don't apply to these quantum measurements. Why? Because it's impossible to get between the particle and the future measurement. Any attempt to do so just becomes a measurement in itself. "Causality" as described by Bell just seems like simplistic philosophy. The very inequalities Bell derived should serve as a counterexample to this notion of "causality".

Re:"Backwards" Causation (2, Funny)

lpp (115405) | more than 4 years ago | (#29232001)

Given that Bell's inequality has been violated routinely

Aren't there laws against that?

Re:"Backwards" Causation (0)

Anonymous Coward | more than 4 years ago | (#29233449)

Given that Bell's inequality has been violated routinely

Aren't there laws against that?

Personally, I've always believed that all particles should be equal in the eyes of the law. Therefore Bell's inequality is innately unjust and violating it (while accepting the consequences of course) is proper civil disobedience.

Re:"Backwards" Causation (2, Interesting)

Anonymous Coward | more than 4 years ago | (#29232003)

Exactly, it seems that most quantum mechanicists assume that the fundamental equations must be hyperbolic in nature. However, general relativity admits solutions with closed time-like curves. This means that a theory combining quantum mechanics and general relativity must as well. (Since in the classical limit it must reduce to general relativity.) Closed time-like curves mean that forward-evolving your hyperbolic equations of motion is impossible. In effect, the loops in time cause future boundary conditions that you must satisfy.

Coarse-graining over the spacetime foam at plank length must include the effect of these small-scale timelike loops. The result of this probably changes the fundamental equations to be elliptic in nature. If this is done, then most of the mystery of quantum mechanics disappears.

As you have said, Bell's inequality requires one of locality or causality to hold. (Most quantum mechanicists assume causality, which then implies that "funny action at a distance" exists.) However, if you drop causality, then the interpretation of wave-function superposition is just your lack of knowledge of future boundary conditions. It becomes a calculational tool to solve your elliptic equations. (Note that the same sum-over-histories technique used in quantum mechanics appears in purely classical situations like a billiard-ball table with a worm-hole that can alter the ball trajectories.)

This interpretation, locality over causality, is so much nicer since it removes the special "measurements" that collapse wave-functions. However, it implies that the universe is a static solution for all time, and has been completely determined. There is no such thing as free will etc. This obviously annoys some people. However, I contend that even if we don't have a free will, we might as well act as if we do, since the future boundary conditions that constrain everything are unknown.

Re:"Backwards" Causation (1, Insightful)

Anonymous Coward | more than 4 years ago | (#29232453)

This interpretation, locality over causality, is so much nicer since it removes the special "measurements" that collapse wave-functions. However, it implies that the universe is a static solution for all time, and has been completely determined. There is no such thing as free will etc. This obviously annoys some people. However, I contend that even if we don't have a free will, we might as well act as if we do, since the future boundary conditions that constrain everything are unknown.

Actually, it does imply free will, just not your free will.

Being able to choose a single path in a branching multiverse implies the existence of a choice function (selection among possibly indistinguishable elements of a set) defined on each branching point.

No matter how you interpret the structure of the universe, there's always at least one choice in there somewhere and your choices are embedded in the universe's choices.

Re:"Backwards" Causation (0)

Anonymous Coward | more than 4 years ago | (#29232755)

The whole point of having elliptic fundamental equations is to avoid any branching, and thus the requirement for any choice function at all. Notice how the wave-function collapse process of measurement loses all importance.

However, you are right that there may be many possible universes due to eternal inflation. This existence of a multiverse does not imply free will. Pretend the multiverse is a pack of cards. Our universe is one of those cards. Which of the 52 we don't know until the end of time when the suit and value are revealed. Another version of yourself might be in a universe with a different suit, but same rank. This person doesn't get to pick that though - it is implicit within the existence of that card within the deck itself.

The 5 of spades does not get to pick to be the 5 of spades... and somewhere within the standard deck lies one card that must indeed be the 5 of spades.

Re:"Backwards" Causation (1)

RoccamOccam (953524) | more than 4 years ago | (#29233303)

I contend that even if we don't have a free will, we might as well act as if we do

Okay, this one is really messing with my head.

Re:"Backwards" Causation (2, Insightful)

medv4380 (1604309) | more than 4 years ago | (#29232093)

However, for particle physics, neither direction of time is privileged.

Einstein's Law of Causality states pretty clearly that Time is Uni-driectional, and you'd have to present a pretty solid proof to disprove the Law of Causality. People have tried but short of building a time machine I'm pretty sure the Law of Causality isn't about to fall just yet.

Re:"Backwards" Causation (1)

etymxris (121288) | more than 4 years ago | (#29233195)

Einstein had a lot of trouble dealing with the results of quantum mechanics. His ERP paradox ironically ended up being a reductio of his own views of causality. If you want to cite authorities on QM, you'll need to look elsewhere.

Re:"Backwards" Causation (3, Informative)

shma (863063) | more than 4 years ago | (#29232625)

Particles are just as likely to be influenced by future interactions as they are by past interactions

This seems to be a poor understanding of time reversal symmetry. Particle physics works if you run time forward, or if you flip its sign and run time backwards. But that does not mean the same thing as what you said above. You can look at an experiment with each event in reverse, but you can't, for instance, say that event 2 was caused by event 1, but event 1 was caused by event 3. It only can follow the laws of physics if the causal order is 123 or 321.

The idea of 'backwards' causation has obvious major problems. First of all, you run into causal paradoxes. But more importantly, if the outcome of your experiment rests on future events, how can you do science? Every result becomes meaningless because you don't know if a future event caused it.

Re:"Backwards" Causation (1)

etymxris (121288) | more than 4 years ago | (#29233143)

First about causal paradoxes. The going back in time to kill your grandfather type of paradox is impossible for the quantum measurements we are talking about. This act of preventing a future event is known as "bilking" and is a pretty sound argument against time travel. However, bilking is impossible for entangled particles. I cannot measure the particle so as to change the future measuring device since the observation becomes the new measurement.

Second about science being impossible. I doubt that. On macroscopic scales not much changes since backward causes are limited and most "causes" actually derive from the entropy decrease of local systems. So far we've only seen entropy increase towards the past. This is a mystery in itself given the largely symmetric nature of particle physics, but is besides the point when we're discussing quantum measurements of single particles where thermodynamics plays little or no role.

Moreover, sometimes science and mathematical calculations are hard. But that's the way the world is and the simplicity of calculations can't stand against the reality of observations. Calculation difficulties have been around since the three body problem.

Finally, I'll address your first point that it's either all forwards or all backwards. Well certainly, if you limit yourself to theories where determination only goes one way, then that must be the case. But that's question begging since the very issue at hand is whether influences can go both ways in time to influence certain events. Typically calculating influences from both directions is not done. But the very point I'm making is that it should be. And it certainly can be done. Cramer's transactional theory is a case in point.

not much of a theory (1)

speedtux (1307149) | more than 4 years ago | (#29232911)

Cramer's transactional theory is an exception, it is symmetric and there is no collapse, but it doesn't get much attention.

As far as I know, Cramer's "theory" doesn't make any testable predictions. Hence, it's not actually a theory, it's more like religion or philosophy.

Spin on it (1)

MosesJones (55544) | more than 4 years ago | (#29231425)

The phrase "spin on it" clearly means different things to different physicists but not having rotational symmetry sounds like more than just a big flaw it sounds like the sort of flaw that you really should try and fix before saying that you've just proved huge numbers of physicists wrong.

Its a mind-bending idea to model the universe in this way and personally I think it will fail because of H2G2

"Some people believe that if man understands the universe then it will be automatically replaced by one even more bizarre and inexplicable, others contend that this has already happened"

Obligatory XKCD (1, Informative)

Anonymous Coward | more than 4 years ago | (#29231541)

http://xkcd.com/505/

Dammit, there goes the planet. (5, Funny)

BigGar' (411008) | more than 4 years ago | (#29231547)

If Stephen Wolfram turns out to be correct, his ego will collapse into a singularity form the rapid mass inflation it will under go, taking the Earth with him.

Re:Dammit, there goes the planet. (1)

maxume (22995) | more than 4 years ago | (#29231967)

So dark matter results from intelligence arising and becoming arrogant?

Who knew.

Re:Dammit, there goes the planet. (1)

0xABADC0DA (867955) | more than 4 years ago | (#29232671)

Actually if Stephen Wolfram turns out to be correct then his ego must be defined by Rule 110 [wolfram.com] which, as has already been proven, is universal; it expands forever and is full of hot gasses.

Einstein dice (0)

Anonymous Coward | more than 4 years ago | (#29231669)

So at last where hidden dice and they were controled with a hidden magnets

Obvious (1)

MarkPNeyer (729607) | more than 4 years ago | (#29231857)

Most likely, I'm missing something here, but this seems obvious to me, as a simple result of the fact that cellular Automata are Turing complete:

A model of the universe is nothing other than an algorithm for converting initial conditions into empirical measurements. Initial conditions and empirical measurements are both describable in terms of numbers. Therefore, any model of the universe is an algorithm for converting numbers into numbers, and thus expressible as a Turing machine. Since cellular automata are Turing complete, any model of the universe is expressible as some cellular automaton. QED, bitches.

As an aside note, the fact that some model (e.g. cellular automaton) is capable of predicting everythign we've experienced in no way implies that the model is 'real' - i.e. that the universe is really a finite automaton / Turing machine.

Re:Obvious (1)

gtall (79522) | more than 4 years ago | (#29233291)

The kicker is that, according to quantum mechanics which t'Hooft is attempting to dispute (I think), some of your numbers will be probabilities. So it isn't like you could predict the position and velocity of an electron. And even the probabilities might not conform to a logic system you would use, they might conform to a quantum logic. So reasoning from your automata might not be entirely straightforward.

How does "no hidden variable" not apply? (1)

gweihir (88907) | more than 4 years ago | (#29231989)

If anybody here can give a short explanation on how this gets around these proofs, I would be grateful. I remember being pretty convonced by the proof and did not see a way around it. Although, personally, I believe that hidden variable fits reality better, as entanglement with non-determinism needs an extension of the model of the Universe, while "hidden variable" can get by without. Being a CS, I prefer simpler solutions any time ;-)

Re:How does "no hidden variable" not apply? (1)

ceoyoyo (59147) | more than 4 years ago | (#29232181)

It allows non-local influences. The hidden variable proof assumes a local universe.

Re:How does "no hidden variable" not apply? (1)

mbone (558574) | more than 4 years ago | (#29232483)

See my response below - it has to be either non-local, non-causal or exceed the speed of light. (These are of course coupled possibilities.) If he has found another way around Bell's Theorem, I bet he would be touting that, not cellular automata.

Re:How does "no hidden variable" not apply? (1)

gweihir (88907) | more than 4 years ago | (#29233547)

Hmm, yes, I think that would do it. Thanks.

Seems to me that the Quantum-Theory people know a lot less at this time than some of them pretend to.

Hilbert Space (1)

neo (4625) | more than 4 years ago | (#29232047)

The invocation of Hilbert space in the article suggests a LINEAR cellular automata. It would suggest the possibility of any two points in space affecting each other through a very long, but singular line. The concept is akin, if I understand it correctly, to saying that the entire universe is one long line in Hilbert space and thus each iteration of movement affects all others.

but, IANAP

A Nonlocal Hidden Variables Theory? (3, Informative)

internic (453511) | more than 4 years ago | (#29232119)

Firstly, I find the title of the submission a little odd. I mean, Entanglement can easily be understood as "deterministic" in a sense in conventional quantum mechanics. The generation of entanglement via the Schroedinger equation is quite deterministic. What's usually understood as non-deterministic is what happens when you measure.

I saw a talk by t'Hooft a number of years ago (I actually had lunch with him and my adviser). He was talking about a similar idea then, and my interpretation was that it evaded Bell's Theorem by being a non-local hidden variables theory. I haven't read the paper, so I'm not certain if this new idea is significantly different.

For background: Bell's Theorem is a result that shows that a local realistic hidden variables theory (a theory where each, say, particle has some hidden degree of freedom that determines the outcome of a measurement on it before the measurement is made) cannot reproduce the results of quantum mechanics for an entangled quantum state. To get around this obstacle, it's generally said that you either have to give up determinism (things don't have one specific state, etc. , before they're measured) or locality (the outcome of an experiment in one place may be totally changed by events happening at the same time arbitrarily far away)

FTFA (0)

Anonymous Coward | more than 4 years ago | (#29232185)

"A two photon state with total spin zero is not an eigenstate of the beables of the theory."

Hidden variables and metaphysics (1)

CustomDesigned (250089) | more than 4 years ago | (#29232251)

As I understand it, there are hidden variable theories completely in sync with experiment. But they are experimentally indistinguishable from true randomness - and hence serve no scientific purpose (although answering Einstein's famous objection, "God does not play dice"). A hidden variable theory where the "hidden" variables can be deduced by experiment "inside" the universe is no longer a truly "hidden" variable theory.

Re:Hidden variables and metaphysics (1)

blueg3 (192743) | more than 4 years ago | (#29233003)

"Hidden" in this sense doesn't mean "impossible to deduce by experiment" but simply "currently unknown to us".

3 choices (4, Informative)

mbone (558574) | more than 4 years ago | (#29232405)

Hidden variables in this case should be thought of as a hidden micro-states. A hidden variable theory would have quantum mechanics be something like thermodynamics; i.e., a theory that is not really basic, but appears so as we cannot see the fine scale true reality. Einstein was convinced that this had to be the case.

The tests of Bell's Theorem shows that no locally causal hidden variable theory is viable. This says basically that one of these must be the case

There are no hidden variables (i.e., true quantum uncertainty applies, and quantum mechanics is correct).

The speed of Light can be violated (i.e., there are hidden states that can exchange information faster than the speed of light). This implies, by the way, causality failures would be possible, so that in principle you could do something like kill your grandfather and prevent your own existence.

There is action at a distance (i.e., the theory is non-local).

There has long been a viable theory, that of Bohm [wikipedia.org], that replicates normal quantum mechanics. It's non-local.

I cannot tell from a read of the article (and without seeing the underlying paper) if 't Hoof has a non-local theory or just how he stays consistent with Bell's Theorem.

Another avenue: Invariant Set Hypothesis (1)

isd.bz (1260658) | more than 4 years ago | (#29232449)

Dr. Tim Palmer wrote a wonderful paper in which he makes an argument which would result in similar implications (disregarding the particular solution of using cellular automata): the Invariant Set Hypothesis [cornell.edu]. I haven't read t'Hooft's paper yet, but I have read and (attempted) understood this paper. He argues that there may be an invariant set behind quantum mechanics that is scale-variant but repetitive (this, if you knew the invariant set, it would be scale invariant). I'm not sure if this the same kind of determinism, but I suspect not.

It's an interesting read, anyhow.

Re:Another avenue: Invariant Set Hypothesis (0)

Anonymous Coward | more than 4 years ago | (#29232813)

I think I had an idea very much like that a few weeks ago. I didn't have a chance to study much quantum mechanics (I was a math major) so I'm not completely sure what I do and don't understand, but I had the thought that if you ran the universe backwards, warped the geometry, and flipped the notion of density and lack of density (i.e. sparsity), you could get time symmetry in that the starting point (a big bang, infinite wave function density) would map onto the end point (an infinitely dispersed wave function).

That lead to me wondering if you could reformulate general relativity so that it warps spacetime in a manner consistent with this backwards mapping. The big bang has an infinitely small space and the point at infinite time has an infinitely large space.

Yes, I know it's obvious I'm out of my depth here, but on occasion I've known my subconscious to come up with ideas that are too complicated for my conscious mind to understand. Yes, I know that sounds crazy, and it probably is.

Does Holographic Universe explain entaglement? (0)

Anonymous Coward | more than 4 years ago | (#29232775)

Entanglement is described as 'spooky action at a distance'. Of course, if what appears to us to be distance really isn't, i.e. if the measured electrons are in some way tightly packed still at the point in time when they are measured, then measuring one can be expected to have a knock-on effect on the other.

If what we see as matter is really a manifestation of the interference pattern of multiple waves, then matter-to-energy is extremely obvious. You simply exert some kind of effort to make them decoherent. Cumulacy applies, so a big thing can be split into smaller, which can be split into smaller again etc. This also explains thermodynamics etc. Matter/antimatter is simply a destructive interference pattern.

In this case, at the point two electrons are emitted, they aren't coherent, just somehow.. close to each other in 'true' 2D space =p At the point you measure, hence which one you measure is really pretty random, because they are both actually in the same space. When you _do_ measure one, then the other one _must_ take on the opposite spin, regardless of where it happens to be in 'fake-3D' space.

The hidden variable is really the position of these waves in 2D space.

Sounds like global warming theory (0)

Anonymous Coward | more than 4 years ago | (#29233409)

The theory is sound, except for the fact that it can't predict reality.

Facinating news for the mathematical universe (1)

Torodung (31985) | more than 4 years ago | (#29233531)

We are describing the universe with mathematics. Mathematics are wholly invented by man. The rules are deterministic. Where we get unexpected results, such as with chaos mathematics, all we can do is map the boundaries and boggle.

Eventually, when you do enough math, everything you can understand about the universe with math alone is going to look deterministic because of the semantic properties of the language you are using to describe it.

So the question is, what are we leaving out by boiling the universe down to a mathematical model, and is that undiscovered area of knowledge worth studying/of use to us? What is the end point of Newton's insistence that God described the universe with math, instead of just Newton alone, projecting his own ideas upon a God that may or may not exist?

I get excited when I see reports like this, because it may indicate a time for a paradigm shift, proven necessary because we've exhausted the mathematical possibilities, and that may lead us to a new revolution in knowledge.

Maybe we'll see technological singularity yet. Is it too much to hope in my lifetime?

Wondrous.

--
Toro

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