Is Determinism a Valid Hypothesis?

Cito di Pense · **#101** by **Cito di Pense** » Apr 05, 2014 4:36 pm

jamest wrote:We're not trying to ban jokes now, are we? C'mon. Enough's enough.

Well, quantum woo is one thing. Skepticism of the Big Ban theory is quite another.

SpeedOfSound · **#102** by **SpeedOfSound** » Apr 05, 2014 5:43 pm

jamest wrote:
SpeedOfSound wrote:
jamest wrote:We're not trying to ban jokes now, are we? C'mon. Enough's enough.

I know!! We would have to ban your philosophy.

I walked right into that one, didn't I?

Yup. But you see it was a joke. So...

susu.exp · **#103** by **susu.exp** » Apr 05, 2014 6:13 pm

DrWho wrote:QM is not well understood...lot's of unanswered questions. I think it's a bit premature to say what's a likely explanation and what is not.

That's a bit handwavy, don't you think? We do know that local realism is false. We can also show that some forms of non-local realism are false. Nobody has proposed a non-local realist theory that doesn't have causal loops and it's not at all clear that such a theory is even possible.

On second though, that's still too weak. Any non-local model without causal loops is equivalent to a local model. We can rule out local realism, so we can also rule out non-local realism without causal loops.

DrWho · **#104** by **DrWho** » Apr 05, 2014 6:42 pm

susu.exp wrote:
DrWho wrote:QM is not well understood...lot's of unanswered questions. I think it's a bit premature to say what's a likely explanation and what is not.

That's a bit handwavy, don't you think? We do know that local realism is false. We can also show that some forms of non-local realism are false. Nobody has proposed a non-local realist theory that doesn't have causal loops and it's not at all clear that such a theory is even possible.

On second though, that's still too weak. Any non-local model without causal loops is equivalent to a local model. We can rule out local realism, so we can also rule out non-local realism without causal loops.

Well, that's quite a conclusion, are you sure that every competent physicist would agree with that claim? I'm not. I don't even think the meaning of deterministic or stochastic universe is entirely clear. Both propositions can be formulated in different ways.

For instance, I take determinism to mean that the outcome of any prediction is necessitated by the initial conditions the system. On this view, determinism is the foundation for the operation of all scientific law. QM make predictions in the form of probabilities, but these probabilities are determined (necessitated) by scientific law applied to initial conditions. In this sense, QM probability is deterministic. One critical question remaining to ask: Is subatomic activity completely or incompletely deterministic?

QM phenomena could not be purely stochastic because then nothing would be even probable. But there is such eagerness to call attention to the part that is random, that the non-random part (the actually useful) rarely gets attention.

SpeedOfSound · **#105** by **SpeedOfSound** » Apr 05, 2014 7:39 pm

susu.exp wrote:
DrWho wrote:QM is not well understood...lot's of unanswered questions. I think it's a bit premature to say what's a likely explanation and what is not.

That's a bit handwavy, don't you think? We do know that local realism is false. ...

oh yeah? And just how do you know that? Please offer your definition of realism and it's implications.

SpeedOfSound · **#106** by **SpeedOfSound** » Apr 05, 2014 7:42 pm

DrWho wrote:
susu.exp wrote:
DrWho wrote:QM is not well understood...lot's of unanswered questions. I think it's a bit premature to say what's a likely explanation and what is not.

That's a bit handwavy, don't you think? We do know that local realism is false. We can also show that some forms of non-local realism are false. Nobody has proposed a non-local realist theory that doesn't have causal loops and it's not at all clear that such a theory is even possible.

On second though, that's still too weak. Any non-local model without causal loops is equivalent to a local model. We can rule out local realism, so we can also rule out non-local realism without causal loops.

Well, that's quite a conclusion, are you sure that every competent physicist would agree with that claim? I'm not. I don't even think the meaning of deterministic or stochastic universe is entirely clear. Both propositions can be formulated in different ways.

For instance, I take determinism to mean that the outcome of any prediction is necessitated by the initial conditions the system. On this view, determinism is the foundation for the operation of all scientific law. QM make predictions in the form of probabilities, but these probabilities are determined (necessitated) by scientific law applied to initial conditions. In this sense, QM probability is deterministic. One critical question remaining to ask: Is subatomic activity completely or incompletely deterministic?

QM phenomena could not be purely stochastic because then nothing would be even probable. But there is such eagerness to call attention to the part that is random, that the non-random part (the actually useful) rarely gets attention.

I agree with you here. I'm not convinced that just because our calculations or measurements are probabilistic that it rules out determinism.

I also think the issue of locality has nothing to do with this.

Cito di Pense · **#107** by **Cito di Pense** » Apr 05, 2014 7:54 pm

SpeedOfSound wrote:
I agree with you here. I'm not convinced that just because our calculations or measurements are probabilistic that it rules out determinism.

I also think the issue of locality has nothing to do with this.

Well, you can make up your own definition of locality, then, and see how it competes. Be sure to publish something, so that we can take you seriously. I wouldn't bother with this kind of obstreperousness if there were not some physics that has something to say about some definition of locality:

http://en.wikipedia.org/wiki/Principle_of_locality

If you define determinism and locality so that they have something to do with each other, then if you can't set boundaries on a system for which you wish to propose a certain (that is, determined) outcome, you have to start thinking about non-locality.

If you just want to fudge a high degree of statistical confidence into philosophical certainty, be my guest.

susu.exp · **#108** by **susu.exp** » Apr 05, 2014 8:40 pm

SpeedOfSound wrote:oh yeah? And just how do you know that? Please offer your definition of realism and it's implications.

Experimental violations of Bells inequality. Realism here means that objects have fixed properties for all possible measurements prior to any measurements being performed. Locality means that for any event A that influences an event B, event B can not also influence A. For any local realistic theory one can show that Bells inequality holds. Which means that the observed violations of the inequality falsify local realism.

DrWho wrote:Well, that's quite a conclusion, are you sure that every competent physicist would agree with that claim? I'm not. I don't even think the meaning of deterministic or stochastic universe is entirely clear. Both propositions can be formulated in different ways.

Am I sure that every competent Physicist would agree? No. But that's somewhat besides the point, isn't it? We're not figuring out science by survey...
On the second part - Whoa, did you really just basically say, after making arguments in more than one thread about determinism that you don't even have a clue what that word means?

DrWho wrote:For instance, I take determinism to mean that the outcome of any prediction is necessitated by the initial conditions the system. On this view, determinism is the foundation for the operation of all scientific law. QM make predictions in the form of probabilities, but these probabilities are determined (necessitated) by scientific law applied to initial conditions. In this sense, QM probability is deterministic. One critical question remaining to ask: Is subatomic activity completely or incompletely deterministic?

Following the admission that you don't know what terms like deterministic and stochastic mean, you nevertheless try to make some statement on them. The predicatble (neccessitated) outcome of this is word salad.

DrWho wrote:QM phenomena could not be purely stochastic because then nothing would be even probable. But there is such eagerness to call attention to the part that is random, that the non-random part (the actually useful) rarely gets attention.

And even less sense here. What the fuck is a "non-random part"? For some reason this term comes up repeatedly with people who have no clue about probability theory and while it makes no sense at all - a random variable is a random variable is a random variable, there's no operation by which you could split it into a "part that is random" and a "non-random part" (unlike a complex number which has a real part and an imaginary part and where you can extract them). But people who talk about this stuff must think it means something and I can not figure out what the heck they think it means.

hackenslash · **#109** by **hackenslash** » Apr 05, 2014 9:10 pm

The difference between a real scientist and a real navel-gazer.

SpeedOfSound · **#110** by **SpeedOfSound** » Apr 05, 2014 9:30 pm

double

SpeedOfSound · **#111** by **SpeedOfSound** » Apr 05, 2014 9:31 pm

susu.exp wrote:
SpeedOfSound wrote:oh yeah? And just how do you know that? Please offer your definition of realism and it's implications.

Experimental violations of Bells inequality. Realism here means that objects have fixed properties for all possible measurements prior to any measurements being performed. Locality means that for any event A that influences an event B, event B can not also influence A. For any local realistic theory one can show that Bells inequality holds. Which means that the observed violations of the inequality falsify local realism.

Which simply means that measurement is a part of what's real.
Further that our model or geometry is not all there is to it.

And I still have the question: What exactly isn't real about what we find according to the evidence we have?

SpeedOfSound · **#112** by **SpeedOfSound** » Apr 05, 2014 9:51 pm

So my question is, what makes you think realism entails science as it was in the 17th century?

susu.exp · **#113** by **susu.exp** » Apr 05, 2014 10:15 pm

SpeedOfSound wrote:Which simply means that measurement is a part of what's real.

I'm not sure what you are getting at there.

SpeedOfSound wrote:Further that our model or geometry is not all there is to it.

Bells inequality applies to all local realistic theories. This includes those we haven't come up with yet. What you say here basically is that you think there might be a local realist theory for which Bells inequality doesn't hold. That's a bit like holding out for an even prime number greater than 2...

SpeedOfSound wrote:And I still have the question: What exactly isn't real about what we find according to the evidence we have?

This doesn't parse. I just told you what realism means. This doesn't seem to be related to that definition at all. Realism in "local realism" means the same as counterfactual definedness.

SpeedOfSound · **#114** by **SpeedOfSound** » Apr 05, 2014 11:43 pm

susu.exp wrote:
SpeedOfSound wrote:Which simply means that measurement is a part of what's real.

I'm not sure what you are getting at there.

SpeedOfSound wrote:Further that our model or geometry is not all there is to it.

Bells inequality applies to all local realistic theories. This includes those we haven't come up with yet. What you say here basically is that you think there might be a local realist theory for which Bells inequality doesn't hold. That's a bit like holding out for an even prime number greater than 2...

No! Not what I am saying at all. Local realist theory? What the hell is that?

SpeedOfSound wrote:And I still have the question: What exactly isn't real about what we find according to the evidence we have?

This doesn't parse. I just told you what realism means. This doesn't seem to be related to that definition at all. Realism in "local realism" means the same as counterfactual definedness.

You just told me what you think realism means to you. Not necessarily what it means. Why would a philosophical notion, realism, have something to say about how the science turns out? Realism means that there is something and it has fuck-all to do with our minds. Nothing else.

But look:

susu.exp wrote:
1. Experimental violations of Bells inequality.
2. Realism here means that objects have fixed properties for all possible measurements prior to any measurements being performed.
3.Locality means that for any event A that influences an event B, event B can not also influence A.
4. For any local realistic theory one can show that Bells inequality holds.
5. Which means that the observed violations of the inequality falsify local realism.
...

(my numbering and breaks)

First note that you are claiming realism is experimentally declared false unless it violates a theory? Is that what the first line means?

Line two is gibberish. It is all the rage to think that there really are realists who think like this though. But read it a few times out loud and you'll see how ridiculous this is.

Four and five seem to combine some theory about physics with realism to yield 'local realism'. What the Fuck? Let go of causality and model this in a linear space and consider that nothing in philosophy has anything to say about one thing affecting another, or in what order, or at what range. Realism in fact says nothing about causality except that whatever we are seeing and labeling as causal is actually happening and not some shit I made up in my head.

Do you see?

What you are doing here is: 'doing metaphysics with science'. Or trying.

DrWho · **#115** by **DrWho** » Apr 06, 2014 12:07 am

susu.exp wrote: What the fuck is a "non-random part"?.

I don't care for your language. It's disrespectful. I'm done 'discussing' this with you.

susu.exp · **#116** by **susu.exp** » Apr 06, 2014 12:20 am

SpeedOfSound wrote: No! Not what I am saying at all. Local realist theory? What the hell is that?

It is a theory, which is local and realist.

SpeedOfSound wrote:You just told me what you think realism means to you. Not necessarily what it means.

I've told you what it means in the context of Bells inequality. It has a precise technical meaning in physics.

SpeedOfSound wrote:Why would a philosophical notion, realism, have something to say about how the science turns out? Realism means that there is something and it has fuck-all to do with our minds. Nothing else.

That's not what the word means when we talk about Bells inequality. It has jack shit to do with minds, it has to do with whether physical objects have certain properties before we measure them or not.

To get into the reasoning behing Bells theorem. We can measure the spin of a particle in 3 orthogonal directions of space: X,Y and Z. For entangled particles, we find that when we measure them along the same axis they always come out opposite. So we know that the spin in any particular direction is opposed. Now we can also measure one particle in one direction and the other in another.
Realism tells us that each particle has a spin in each direction.
Locality tells us that once the particles are apart they can't influence one another. In particular one particle can't "know" that we have measured the spin on the other and in which direction.

So let's look at the possibilities. To ensure that if we measure the same directions they come out opposite, the spin of the particles has to follow one of two classes of rules:
One always has a spin in one direction, the other in the opposite direction. In this case all measurements would show opposites, no matter which directions we choose.
One has a spin in one direction for two axis and opposed for the third, the other ones is opposed to that. In that case we will find opposites in 5 out of 9 cases.

We could have both intermixed, so if both locality and realism hold, we would find opposed spins in somewhere between 55.56% and 100% of cases. That's the inequality. These experiments have been performed and the result is that we find it in 50% of the cases. That's at odds with local realism. You can drop one of the two, but you can't preserve both.

SpeedOfSound wrote:First note that you are claiming realism is experimentally declared false unless it violates a theory? Is that what the first line means?

The first line means that we have experimentally found that Bells inequality does not hold. Since it arises from the assumptions of local realism, either realism or locality (or even both) are false.

SpeedOfSound wrote:Line two is gibberish. It is all the rage to think that there really are realists who think like this though. But read it a few times out loud and you'll see how ridiculous this is.

See above. We measure the spin of a particle in one direction. Does it make sense to say that the particle has a spin in another direction? Consider that we could have measured it in that direction.

DrWho · **#117** by **DrWho** » Apr 06, 2014 12:48 am

http://www.mathematik.uni-muenchen.de/~ ... las_BA.pdf

DrWho · **#118** by **DrWho** » Apr 06, 2014 12:53 am

http://arxiv.org/pdf/gr-qc/9412005.pdf

DrWho · **#119** by **DrWho** » Apr 06, 2014 1:04 am

To conclude, I would say that not only is a refutation of determinism
essentially impossible, but not the slightest argument
in favour of that idea is to be found in modern physics, whether
in chaos theory or in quantum mechanics. What is strange is that
Bohm’s theory is so widely unknown and that the mere existence of
such a theory is so widely considered impossible. John Bell was one
of the most lucid proponent of Bohm’s theory and noboby protested
better than him against that state of affairs. He exlains that, when
he was a student, he had read Born’s book, Natural Philosophy of
Cause and Chance [4], where, on the basis of a misunderstanding
of the significance of von Neumann’s no hidden variable theorem,
he was making the claim quoted above36. But, as Bell says, “in
1952, I saw the impossible done”; and that was Bohm’s theory. He
continues:
But then why had Born not told me of this ‘pilot wave’?
If only to point out what was wrong with it? Why did von
Neumann not consider it? More extraordinarily, why did
people go on producing ‘impossibility’ proofs, after 1952,
and as recently as 1978? When even Pauli, Rosenfeld, and
Heisenberg, could produce no more devastating criticism
of Bohm’s version than to brand it as ‘metaphysical’ and
‘ideological’? Why is the pilot wave picture ignored in text
books? Should it not be taught, not as the only way, but as
an antidote to the prevailing complacency? To show that
vagueness, subjectivity, and indeterminism, are not forced
on us by experimental facts, but by deliberate theoretical
choice? [2], p. 160.

Jean Bricmont

http://www.dogma.lu/txt/JB-Determinism.pdf

ughaibu · **#120** by **ughaibu** » Apr 06, 2014 3:24 am

DrWho wrote:
I would say that not only is a refutation of determinism
essentially impossible, but not the slightest argument
in favour of that idea is to be found in modern physics
Jean Bricmont
http://www.dogma.lu/txt/JB-Determinism.pdf

The above is plain false. Conway and Kochen's strong free will theorem proves that if physicists can choose the settings of their measuring apparatus, then determinism is false, according to modern physics. However, determinism is a metaphysical thesis, regardless of the fact that there is no reason to think that we live in a determined world and a whole string of ways to construct arguments against the claim that we do, we cannot demonstrate the fact physically.

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