Is a-causality necessary for randomness?

[San K]

What is the relationship between a-causality and randomness?

Let's look at the argument below:

For something to be (truly/inherently) random there cannot be a cause.

Because, if there is a cause then the cause can be studied and the result/output can be predicted and hence there would no randomness.

True Randomness means something that cannot be predicted.

We can predict whether will be an interference pattern or not, however we cannot predict the location of any individual/single photon/electron on the screen.

We can, in principle, predict the results of a roll of a dice (or toss of a coin) if we took into account all the factors such initial forces on the dice during the toss, effect of air molecules etc. Since the roll of a dice has a cause its predictable.

 

[bhobba]

An observation causes a quantum system to change state - we just can't predict what that state will be - but 100% for sure it caused it to change state - the change was not a-casual.

In classical 100% deterministic systems chaotic behaviour abounds meaning since it is impossible to know with 100% accuracy the initial conditions there will always be some imprecision in knowledge that will grow to the point prediction is meaningless.

Thanks
Bill

 

[VortexLattice]

This seems a tad philosophical but... at the very least, it seems like you could have a perfectly reasonable "cause" for a "random" process, but the cause is necessarily hidden. I think that's the same as Hidden Variable Theory, which is I guess wrong because of Bell's Theorem, but I don't know exactly why.

 

[JPBenowitz]

This isn't true. Nothing is truly random, even quantum mechanics. Although QM may seem completely random it isn't, it's just that we can never acquire the necessary information to determine precisely how the system will evolve.

 

[Zarqon]

This isn't true. Nothing is truly random, even quantum mechanics. Although QM may seem completely random it isn't, it's just that we can never acquire the necessary information to determine precisely how the system will evolve.

This is not known. All we can say is that we measure what appears to be a truly random phenomena when we measure quantum states. Although there exists deterministic explanations these are just speculations and have not been proven. At this point it is still an open question on whether the universe is really random or deterministic.

 

[bhobba]

This isn't true. Nothing is truly random, even quantum mechanics. Although QM may seem completely random it isn't, it's just that we can never acquire the necessary information to determine precisely how the system will evolve.

What can be said is a process that passes all tests for randomness may be truly random but of course we can never know if its the result of some deterministic process that has not been discovered yet and that process just happens to mimic randomness - tests for true randomness are pretty good these days and only some very sophisticated algorithms can actually pass it. If you believe nature just happens to be that 'good' - well it is a logically valid position - but I do not ascribe to it. Occams razor would suggest if we know of no underlying deterministic process and it passes randomness tests then the simplest explanation is it really is random.

And as far as we can tell today QM is utterly and truly random eg random number generators based on thermal noise which is quantum in origin I am pretty sure pass every known test for randomness that even some reasonably sophisticated pseudo generators fail - although pseudo generators do exist that do pass those tests.

Thanks
Bill

 

[Maui]

Shouldn't 'truly random' be regarded as the approximately 50/50 distribution of outcomes of hundreds of trials? If you toss a coin 222 times and it lands on tails approximately 111 times, it means it is truly random because nothing unobservable can be said to be affecting its 50/50(1 of 2) possibile outcomes. Does anyone object to this definition?

Electrons and other fundamental particles do not obey the 50/50 statistics so they cannot be truly random. For reference, just look at the interference pattern from single electrons in a double slit experiment. I don't see how we could observe a Newtonian(-like) universe based on a truly random quantum foundation. It would fall apart immediately, wouldn't it?

 

[San K]

Electrons and other fundamental particles do not obey the 50/50 statistics so they cannot be truly random. For reference, just look at the interference pattern from single electrons in a double slit experiment. I don't see how we could observe a Newtonian(-like) universe based on a truly random quantum foundation. It would fall apart immediately, wouldn't it?

Each of the fringes has a fixed probability of the electron/photon landing up on it, I thought...for a given experimental setup (slit width and distance, electron distances etc).

So conceptually the 50/50 i.e. fixed probability (totaling to 1), concept applies.

 

[Maui]

Each of the fringes has a fixed probability of the electron/photon landing up on it, I thought...for a given experimental setup (slit width and distance, electron distances etc).

So conceptually the 50/50 i.e. fixed probability (totaling to 1), concept applies.

The subtlety lies in the fact that the fringes are formed by the accumulation of thousands of single dots(landings). It's as if the electron travels as a wave through the slits but lands on the detection screen as a particle. After many many landings accumulate, we get the interference pattern and this is anything but random. It's so much more on the holistic side, that calling it random seems to require a re-definition of "randomness".

 

[audioloop]

What is the between a-causality and randomness?

Let's look at the argument below:

For something to be (truly/inherently) random there cannot be a cause.

Because, if there is a cause then the cause can be studied and the result/ can be predicted and hence there would no randomness.

Randomness means something that cannot be predicted.

We can predict whether will be an interference pattern or not, however we cannot predict the location of any individual/ photon/electron on the screen.

We can, in principle, predict the results of a roll of a dice (or toss of a coin) if we took into all the factors such initial forces on the dice during the toss, effect of air molecules etc. Since the roll of a dice has a cause its predictable.

unpredictability does not imply the lack of a cause, we can't confound determinism with predictability (or indeterminism with unpredictability)
a-causality have to do with indeterminism but indeterminism does not have a relationship with randomess.

by the way there are deterministic theories without being computable i.e. nopredictable outcomes and indeterministic process can produces a non-random sequence of outcomes.

 

[JPBenowitz]

What can be said is a process that passes all tests for randomness may be truly random but of course we can never know if its the result of some deterministic process that has not been discovered yet and that process just happens to mimic randomness - tests for true randomness are pretty good these days and only some very sophisticated algorithms can actually pass it. If you believe nature just happens to be that 'good' - well it is a logically valid position - but I do not ascribe to it. Occams razor would suggest if we know of no underlying deterministic process and it passes randomness tests then the simplest explanation is it really is random.

And as far as we can tell today QM is utterly and truly random eg random number generators based on thermal noise which is quantum in origin I am pretty sure pass every known test for randomness that even some reasonably sophisticated pseudo generators fail - although pseudo generators do exist that do pass those tests.

Thanks
Bill

My position isn't necessarily that QM isn't "truly random" but what it means to be truly random. For instance we cannot know both the position and momentum of a particle precisely because observing it changes it; in other words the very act of observation constrains the observer to how much information can possibly be extracted from any given system. Because of this information constraint we cannot know precisely the initial conditions of any system to predict a precise outcome. Does this mean that the universe is intrinsically deterministic? Not necessarily because no observer could possibly compute the future--the future remains completely hidden. The universe isn't exactly deterministic or truly random in this sense.

 

[JPBenowitz]

unpredictability does not imply the lack of a cause, we can't confound determinism with predictability (or indeterminism with unpredictability)
a-causality have to do with indeterminism but indeterminism does not have a relationship with randomess.

by the way there are deterministic theories without being computable i.e. nopredictable outcomes and indeterministic process can produces a non-random sequence of outcomes.

Randomness is really just chaos. Where predicting the outcome in a chaotic system requires hefty computation. True Randomness is where a chaotic system cannot have a predicted outcome because of a fundamental computational limit.

 

[audioloop]

Randomness is really just chaos. Where predicting the outcome in a chaotic system requires hefty . True Randomness is where a chaotic system cannot have a predicted outcome because of a fundamental computational limit.

another confusion,
Chaos involves deterministic process i.e. no random.

A deterministic system will have an error that either remains small (stable, regular solution) or increases exponentially with time (chaos). A stochastic system will have a randomly distributed error*, these systems are deterministic, meaning that their future behavior is fully determined by their initial conditions, with no random elements involved**.*Casdagli, Martin. "Chaos and Deterministic versus Stochastic Non-linear Modelling", in: Journal Royal Statistics Society: Series B
**Kellert, Stephen H. (1993). In the Wake of Chaos: Unpredictable Order in Dynamical Systems. University of Chicago Press.
Lorenz, Edward N. (1963). "Deterministic non-periodic flow". Journal of the Atmospheric Sciences 20 (2): 130–141

 

[JPBenowitz]

another confusion,
Chaos involves deterministic process i.e. no random.

A deterministic system will have an error that either remains small (stable, regular solution) or increases exponentially with time (chaos). A stochastic system will have a randomly distributed error* these systems are deterministic, meaning that their future behavior is fully determined by their initial conditions, with no random elements involved**.


*Casdagli, Martin. "Chaos and Deterministic versus Stochastic Non-linear Modelling", in: Journal Royal Statistics Society: Series B
**Kellert, Stephen H. (1993). In the Wake of Chaos: Unpredictable Order in Dynamical Systems. University of Chicago Press.
Lorenz, Edward N. (1963). "Deterministic non-periodic flow". Journal of the Atmospheric Sciences 20 (2): 130–141

That's literally what I am saying. Randomness is really just a deterministic system with an error that increases exponentially. True Randomness is when that error exceeds all computational possibilities on a fundamental physical level.

 

[Zarqon]

That's literally what I am saying. Randomness is really just a deterministic system with an error that increases exponentially. True Randomness is when that error exceeds all computational possibilities on a fundamental physical level.

You have to be careful with your statements. I don't think this has been shown at all. It might work like that but you can't make a statement saying it's certain that it does work like that because it has not been proven (and if you think it has been proven could you find some sources for your claim?).

 

[bhobba]

You have to be careful with your statements. I don't think this has been shown at all. It might work like that but you can't make a statement saying it's certain that it does work like that because it has not been proven (and if you think it has been proven could you find some sources for your claim?).

Indeed.

Thanks
Bill

 

[JPBenowitz]

You have to be careful with your statements. I don't think this has been shown at all. It might work like that but you can't make a statement saying it's certain that it does work like that because it has not been proven (and if you think it has been proven could you find some sources for your claim?).

You are correct I do not think it has been proven. Which is precisely why I am going to explore this avenue. I'll get back to you on what I find :)

 

[QuantumHop]

What is the relationship between a-causality and randomness?

Let's look at the argument below:

For something to be (truly/inherently) random there cannot be a cause.

Because, if there is a cause then the cause can be studied and the result/output can be predicted and hence there would no randomness.

True Randomness means something that cannot be predicted.

We can predict whether will be an interference pattern or not, however we cannot predict the location of any individual/single photon/electron on the screen.

We can, in principle, predict the results of a roll of a dice (or toss of a coin) if we took into account all the factors such initial forces on the dice during the toss, effect of air molecules etc. Since the roll of a dice has a cause its predictable.

"Random" is a thirteenth century word, it was never brought into human language to be used in science. Randomness cannot be created using mathematics and I don't believe it takes place in nature, all my spidey senses say its impossible.

If a radioactive particle decays and you say it just happened "randomly" then it would be an effect without a cause, that's insane. I don't know what gave the signal for the particle to decay but it makes more sense to me to say I'm unable to see what gave the signal and therefore (to me) its unpredictable.

Mathematics produces statistically random numbers so why wouldn't nature just use them instead of performing a magic trick. If they would just throw away the word random and replace it with unpredictable or unknowable I could sleep at night.

Pseudo randomness is real, random is a figment of the human imagination.

Either that or I'm just a nut job

 

[bhobba]

If a radioactive particle decays and you say it just happened "randomly" then it would be an effect without a cause, that's insane.

You are not a nut job - simply very ingrained in classical thinking. It has a cause - the act of interacting with the environment causes it to decohere and for the particle decay to manifest in some kind of observational apparatus. This is exactly the same as any other quantum observation with decoherence taken into account. It has a property before observation such as a particle present or not present - the theory simply does not predict it with certainty - only probabilities. Do you consider flipping a coin insane because you can't predict if its heads or tails - but you know its a head or tail. I don't and most people (actually everyone) I know doesn't. This is purely a matter of getting used to a world view that is slightly different - that's all - nothing mind boggling weird to the point its insane weird - weird yes - insane - no.

Thanks
Bill

 

[QuantumHop]

You are not a nut job - simply very ingrained in classical thinking. It has a cause - the act of interacting with the environment causes it to decohere and for the particle decay to manifest in some kind of observational apparatus. This is exactly the same as any other quantum observation with decoherence taken into account. It has a property before observation such as a particle present or not present - the theory simply does not predict it with certainty - only probabilities. Do you consider flipping a coin insane because you can't predict if its heads or tails - but you know its a head or tail. I don't and most people (actually everyone) I know doesn't. This is purely a matter of getting used to a world view that is slightly different - that's all - nothing mind boggling weird to the point its insane weird - weird yes - insane - no.

Thanks
Bill

I can accept that 13.7 billion years ago space and time sprang into existence even though it didn't have a place to happen. I can believe that every time the universe needs to make a decision it splits in two. And I can believe in the existence of multiple realities just so long as none of them can generate a random number

Imagine a universe where a small plastic computer is in charge of creating motion in some particles, the computer runs its program and instructs all the various particles to start moving. It gets so hot with all this movement that the computer melts. From that moment in time it would look like the particles were moving randomly. In reality the motion would be pseudo random and the cause no longer exists.

I could invent dozens of ways to create the illusion of randomness but not one to create true randomness.

For the universe to be able to create randomness it has to be capable of making a decision, since I view the universe as mathematical then its impossible for it to make a "choice"

The difference between something being truly random or just unpredictable is colossal.

What possible mechanism could the laws of nature use to make a "choice"

 

[QuantumHop]

Its like asking what came first the chicken or the egg but replacing the chicken and egg with cause and effect.

I would ask what came first cause or effect and you would answer "effect"

 

[bhobba]

For the universe to be able to create randomness it has to be capable of making a decision, since I view the universe as mathematical then its impossible for it to make a "choice"

I view the universe as mathematical as well. But why you think being unable to predict the outcome of an observation with certainly involves the universe making a decision has me beat. Mathematically all randomness means is the long term proportion of some outcome reaches a stable limit - nothing to do with decision making of any type.

I don't believe in the MWI rubbish splitting into different realities etc etc - its mystical nonsense IMHO. But hey - to each their own.

Thanks
Bill

 

[bhobba]

Its like asking what came first the chicken or the egg but replacing the chicken and egg with cause and effect. I would ask what came first cause or effect and you would answer "cause"

Precisely why do you believe the inability to predict something means it has no cause?

Thanks
Bill

 

[QuantumHop]

I view the universe as mathematical as well. But why you think being unable to predict the outcome of an observation with certainly involves the universe making a decision has me beat. Mathematically all randomness means is the long term proportion of some outcome reaches a stable limit - nothing to do with decision making of any type.

I don't believe in the MWI rubbish splitting into different realities etc etc - its mystical nonsense IMHO. But hey - to each their own.

Thanks
Bill

If you also think that the universe is mathematical then why would you allow aspects of it to be random when there's no such thing as random in maths. you could observe a moving particle but you wouldn't know if it was in motion because another particle hit it (cause) or it was in motion because of some particle decaying (effect)

 

[QuantumHop]

Precisely why do you believe the inability to predict something means it has no cause?

Thanks
Bill

Aaaaaaagh I got that the wrong way round, I should have said.

I would ask what came first cause or effect and you would answer "effect"

 

[QuantumHop]

If all the particles were just sat there motionless and then for no apparent reason they started to decay (an effect without a cause) and then all those particles start moving around and bumping into each other the net result is there is more effect in the motion of those particle then the cause of bumping into each other, that's crazy.

 

[QuantumHop]

Sit down and try to make a computer program "guess" the outcome of rolling a dice "without using any random function" and you will find its impossible. This is why I'm making a such a big deal over the difference between truly random and just unpredictable. It sounds the same and it yields the same results but deep down one is possible and the other isn't.

 

[bhobba]

If all the particles were just sat there motionless and then for no apparent reason they started to decay (an effect without a cause) and then all those particles start moving around and bumping into each other the net result is there is more effect in the motion of those particle then the cause of bumping into each other, that's crazy.

QM does not say that. Have you actually studied what QM says from a book like QM - A Modern Development by Ballentine? What it says is the outcome of an observation can't be predicted with certainty. Indeed the idea of particles having a definite position for any length of time is not possible so the idea particles just sitting there motionless is silly.

I suspect your view of QM has been too strongly influenced by pop sci accounts.

Again particle decay has a cause - environmental decoherence. We simply can't predict when the decay will occur.

Thanks
Bill

 

[bhobba]

It sounds the same and it yields the same results but deep down one is possible and the other isn't.

Since it is observationally identical have you considered your discomfiture lies within your classically formed intuition rather than nature? Why not face nature on it own terms rather than how you think it should behave? The only difference between throwing a dice and QM is the outcome of the dice can in principle be predicted with sufficient information (although getting that information with enough accuracy to do it is a challenge) and the outcome of an observation is not - they both have a cause - its simply a matter what in principle can be predicted. The idea everything can be predicted with enough information is not something that a-priori must be true.

Thanks
Bill

 

[QuantumHop]

the outcome of an observation can't be predicted with certainty.

I have no problem with that.

the idea of particles having a definite position for any length of time is not possible so the idea particles just sitting there motionless is silly.

I realize that, Its just the easiest way I could think of to explain that the sum total of all motion of all particles is more the result of effect than cause. (although you now clear things up a few lines down)

I suspect your view of QM has been too strongly influenced by pop sci accounts.

Absolutely, the 60's were simple. When they put Armstrong on the moon I was wondering why they didn't just pile cardboard boxes on top of each other and climb up.

Again particle decay has a cause - environmental decoherence. We simply can't predict when the decay will occur.

Now you hit the nail on the head and I can sleep, the particle didn't just decay randomly it has a cause, randomness has been replaced with unpredictability and the universe is behaving itself.

Random means something happened without any clear instruction or cause, unpredictable means it appears random but only because the cause is unknown. The idea of randomness gives me nightmare

 

[bhobba]

Random means something happened without any clear instruction or cause, unpredictable means it appears random but only because the cause is unknown. The idea of randomness gives me nightmare

Within what I think your conception of randomness is (being something that just happens spontaneously) I am inclined to agree but without going into the details that would not be my view about randomness which I equate with unpredictability.

Thanks
Bill

 

[Zarqon]

Random means something happened without any clear instruction or cause, unpredictable means it appears random but only because the cause is unknown. The idea of randomness gives me nightmare

Also you have to acknowledge the difference between what you want to be true and what has actually been established with experiments. Science is not based on your nightmares or on spidey senses.

All we see is that if you put an atom into a superposition state of 0 and 1 and then make a measurement in the computational basis, there is no way of predicting if the outcome will be 0 or 1. Although there are potential deterministic explanations, at this point, it is simply not possible for us to scientifically choose between true randomness or determinism + additional stuff (such as many worlds). Both are possible and no known experiment can set them apart, so for all practical purposes, true randomness does exist.

If you don't like it, feel free to pick one of the deterministic interpretations to believe in, but you can't go around claiming that true randomness is "figment of the human imagination", because that is simple a false statement, since no such thing has been established.

 

[Maui]

Precisely why do you believe the inability to predict something means it has no cause?

Thanks
Bill

To play devil's advocate - why do you believe that in a quantum universe best described by fields and operators, causality plays a fundamental role(except for ordering events so that they seem to make some sense to you)?

 

[bhobba]

To play devil's advocate - why do you believe that in a quantum universe best described by fields and operators, causality plays a fundamental role(except for ordering events so that they seem to make some sense to you)?

Without posting the detail non relativistic QM follows from observations of invariance of observational outcomes when expressed in the language of linear algebra and Gleasons Theorem which shows, again from invariance, the outcomes of observations must be probabilistic - determinism is not possible. So the answer is I believe nature is at rock bottom simple and the outs of such things as Bohmian Mechanics is ugly because it is contrived, contextual and not invariant. Fields follow from the desire to treat space and time on equal footing which means position operators must also be a label like time is ie is a field.

But aside from such theoretical considerations physics is an experimental science and QM and QFT are fully in accord with experiment.

Why do people want to have nature working in ways that conform to their intuition and want to introduce mathematically ugly things like non contextuality rather than simply assume the outcome of measurements is invariant to other things you happen to be measuring at the same time and go for something like BM?

Actually I don't expect you to answer that - its because they have pre-conceived ideas on how they think nature should work just as I do. That's all discussions in this vein are about - each side airing their prejudices and why they never get anywhere - except to possibly clear up misconceptions.

So let's turn it around again - why don't you - assuming of course you don't.

Thanks
Bill

 

[JPBenowitz]

Since it is observationally identical have you considered your discomfiture lies within your classically formed intuition rather than nature? Why not face nature on it own terms rather than how you think it should behave? The only difference between throwing a dice and QM is the outcome of the dice can in principle be predicted with sufficient information (although getting that information with enough accuracy to do it is a challenge) and the outcome of an observation is not - they both have a cause - its simply a matter what in principle can be predicted. The idea everything can be predicted with enough information is not something that a-priori must be true.

Thanks
Bill

This is the position I was presenting. What it means to be be truly random is not well defined and may very well be a causal event which does not commute enough information to determine which event took place first. If it is impossible for an observer to distinguish causality that QM will appear to be perfectly random. This is an interpretation of hidden variable theory where the information of the system is effectively hidden from the observer.