Looking for explanation of randomness.

[WARTORIOUS]

Hi all, for some time I have been wondering about something I’m not too sure on. Please could someone tell me how randomness can exist? That is to say on a molecular level, or on any level things happening without cause or justification? Patterns may be too hard for us to currently understand or predict however it would be wrong to say because of that randomness exists.

In a universe described by some driven by chance some have said anything can happen. I once heard a scientist say in all seriousness say there’s a chance we could disappear and reappear in Mars then reappear here. Would like an explanation of how true randomness can exist.

By saying that there’s a chance anything can happen your implying there is randomness on a large scale, also in a more Newtonian universe there can not be infinite dimensions, parallel universes because things can only ever happen one way.I believe that if something moves on a molecular level it’s because of forces acting on it.

 

[Danger]

Hi, Wartorious. Welcome to PF.
On the macro scale, you are correct. Everything happens as a consequence of preceding events. The problem is that when you get down to the quantum level, where those preceding events take place, there is no predictability. (Clarification: you can predict the probability of something happening, but not the certainty of it.) Heisenberg showed that, and it hasn't been refuted. On a lesser scale than your Martian example, all of the gas molecules in a sealed container could end up on one side, leaving a vacuum on the other. The odds of it happening, however, are vanishingly small. When you get into stuff like quantum tunnelling, virtual particles, etc., there are simply too many variables to even consider tracking accurately. We don't even know, for example, how many different subatomic particles there are. Right now, they're trying to find the Higgs bosun and graviton and maybe a couple of others. Every time that a new 'brane or string or whatever theory comes up, it suggests new and more exotic particles. Bottom line, we are not even close to understanding how the Universe works. It seems pretty well established, though, that it is ultimately based upon randomness.
This is not one of my more knowledgeable areas, so I'll leave any further discussion to the experts.

 

[MeJennifer]

Please could someone tell me how randomness can exist?

Well how can anything exist? Randomness is just an instance of that particular problem.

Patterns may be too hard for us to currently understand or predict however it would be wrong to say because of that randomness exists.

Why would it be wrong?

 

[WARTORIOUS]

We can assume we exist. Randomness is however much more hypothetical.

Why would it be wrong?

So randomness is a tool, like numbers to make up our lack of understanding of the universe? If something’s hard currently to measure you would say it can never be measured or predicted because its random? I don’t deny the universe may be incredibly complicated and measuring things in chance a useful way of thinking yet the universe, I believe is balanced and acts without chaos or randomness. If partials were to react erratically without any kind of forces making them act that way then I don’t believe complicated structures could ever exist like they do now. We may call the sky blue, yet its not blue, its just a label we place on it, yet because we call the shy blue then we change the perception of the sky and start to corrupt the truth, I have seen the sky be every colour of the rainbow yet we still call it blue.

If we call the universe random then surly we will put less effort into understanding the true cause of things. I would like to see the jar of gas becoming half unpressurised and even if it did I believe there would be a cause of it and would not prove randomness nesseraly.

 

[MeJennifer]

We can assume we exist. Randomness is however much more hypothetical.

Your question was how can randomness exists.

So randomness is a tool, like numbers to make up our lack of understanding of the universe?

We are talking about if elements of nature have intrinsic randomness right? Then how is this question relevant?

If something’s hard currently to measure you would say it can never be measured or predicted because its random?

No.

I don’t deny the universe may be incredibly complicated and measuring things in chance a useful way of thinking yet the universe, I believe is balanced and acts without chaos or randomness.

Well if you believe that then what is your question? You seem to have made up your mind that the universe cannot be random. So what then is there to discuss?

If we call the universe random then surly we will put less effort into understanding the true cause of things.

Well if you postulate that nothing in the universe is random then it is logical that any person making a statement concerning the randomness of the universe has not "truly understood" it.

So this topic does not seem to be a query but rather a sermon. "Nothing in the universe is random and anybody who says that something is not random simply does not truly understand it".

 

[vanesch]

Hi all, for some time I have been wondering about something I’m not too sure on. Please could someone tell me how randomness can exist?

It is quite a subtle issue and people are still debating what randomness is. Part of the answer is rather simple: randomness is ignorance. When we assign probabilities to events, it is because we don't know them precisely. Randomness is the essential aspect of a signal (if you're on the receiving end): you will get one of different possible messages, but you don't know which one. This makes the "signal", before you received it, a "random quantity". And here we see the "ignorance" part: the emitter DID know, and for the emitter, the signal is of course NOT random.
You can get quite far already with the view that randomness describes ignorance. However, the question remains: is ALL randomness, simply reducible toignorance ? Or are there other forms of randomness in nature ? (sometimes called irreducible randomness).
Note that here, one should make a clear distinction between related concepts: determinism, causality, "free will", ... because often one confuses them when talking about randomness.

 

[3trQN]

I am of a beleif that although we can observe randomness, it is only so because we lack the resolution or understanding of the mechanisms underlying that variation.

Admitedly i don't fully understand things, but this is my stance until i can prove firmly to myself otherwise or that my hypothesis/beleif is true or false.

When i consider this, i think the universe to be ultimatley entireley deterministic. Randomness is then just a psuedo randomness brought about by a lack of complete knowlage of the process, that is the Seed or source and the function or equations that generate that randomness.

I take the anthropic principle and the big bang as possible mechanism that, although i admitedly don't fully understand, will help me decide if this stance is correct or not.

Take for example the flip of a coin.

When we toss a coin, the outcome is said to be random, with a 50/50 chance of either outcome. I dispute this, i would say that the outcome of the toss is entirley determined by the initial variables that go into the "flick" and that these variables are essentially deterministic, however extremley chaotic and difficult to predict.

I look more at probabillity as a way of describing situation where we lack complete information.

I know that this is most likley an incorrect model, but i look forward to learning the outcome regardless.

 

[sneez]

i see we use words as determinism and initial variables and randomness. I think we make assumed understood connection in our posts. They are related but in physics very different level than in spoken everyday language. Plus there is pure mathematical randomness (for which i recommend mr chaitin's book, meta math).

Chaos theory which may connect determinism, randomness and initial variables is in simple word non-linearity. Such systems may be deterministic, but unpredictable and mainly unrepeatable in reality.

psuedo randomness brought about by a lack of complete knowledge

nope, one may know completely equations governing a system but still get unpredictability.

Given that we may never know with infinite precision initial conditions of a system, we are bound by certain unpredictability in certain systems.

 

[3trQN]

yes I am afraid my maths is too weak to fully understand these terms, thanks for the explanation though.

 

[WARTORIOUS]

Well if you postulate that nothing in the universe is random then it is logical that any person making a statement concerning the randomness of the universe has not "truly understood" it.

So this topic does not seem to be a query but rather a sermon. "Nothing in the universe is random and anybody who says that something is not random simply does not truly understand it".

I did find the above quote slightly insulting, however I don’t mind. Was trying to justify my opinion and understand others.

Thanks, I do feel I understand better, although I’m not sure why it’s in the philosophy bit however nearly all the modern theories involve as much Rationalism as empiricism so I am not too insulted.

Thanks all

 

[-Job-]

An important variable is the degree of freedom of these random events. If events are random, but over a finite interval, then some structure may arise out of it.
For example, a given particle's position 1 second from now might be considered a random variable, but this random variable is over a finite interval. The reason is that the particle can't travel faster than the speed of light, so 1 second from now its position is random but within a given radius of the original position. So the particle, whose position 1 second from now is random, is guaranteed to be within a certain finite region of space.
There is then the possibility of some certainty arising out of an underlying randomness.
At a more macroscopic scale, it might be that any given random variable's "freedom" is so small, by comparison, that the Universe, from this macroscopic perspective behaves as a deterministic Universe; even though there is an underlying randomness to events.
I think, to go further, it might be possible to show that for every Universe in which no random variables have "infinite freedom", there must be a scale large enough, such that, at that scale, that Universe behaves deterministically. This could be due to what we might call "loss of precision".

Loss of precision happens in computers because computers have a finite amount of storage for each number causing numbers to be truncated/rounded. If a number's randomness freedom is tiny, then an eventual loss of precision will eliminate the randomness of that number. Similarly at a large enough scale, if an event's randomness freedom is tiny, an eventual loss of precision will eliminate the randomness of that event.

 

[vanesch]

When i consider this, i think the universe to be ultimatley entireley deterministic. Randomness is then just a psuedo randomness brought about by a lack of complete knowlage of the process, that is the Seed or source and the function or equations that generate that randomness.

As I said, "randomness", "causality" and "determinism" are usually mixed with each other.

Determinism means that there is some causal structure (each event has its own past and future), and that, given all there is to know about an events past, the laws of nature determine uniquely what happens at said event ; in other words, there is no freedom of any choice anymore.

However, there's a difference between determinism and randomness. Determinism has something to do with "predicting the future", while randomness has a priori no link with any causal or temporal flow. Randomness applies as well to the past as to the future. Randomness means "one out of many". You have one corpse, and 6 potential murderers. Who did it, is random, until you find more evidence.
The outcome of a football game is random (even if the game is over), until you learn about it (by watching the video or hearing it on the radio or something).

For instance: is the assignment of your telephone number "random" ?
Are numbers from a pseudo-random number generator algorithm "random" ?

When we toss a coin, the outcome is said to be random, with a 50/50 chance of either outcome. I dispute this, i would say that the outcome of the toss is entirley determined by the initial variables that go into the "flick" and that these variables are essentially deterministic, however extremley chaotic and difficult to predict.

I look more at probabillity as a way of describing situation where we lack complete information.

Yes, what a deterministic time evolution does, is to link the randomness of the outcome with the randomness of the initial state. Your ignorance of the outcome is equal to your ignorance of the initial state.
And if you apply the deterministic time evolution in the -t direction, it works in the other way: what is the randomness of the initial state, given that I know the outcome.

However, we are confronted also with quantum mechanics, which seems to indicate that there is some irreducible random element in nature. And then, it doesn't even make sense to say so, because every theory which is random, can be replaced with a theory which is deterministic and which has "hidden variables". So be careful when asking what is "randomness" while thinking about "the laws of nature".

So maybe your question is: "is nature deterministic" ?

 

[3trQN]

However, we are confronted also with quantum mechanics, which seems to indicate that there is some irreducible random element in nature. And then, it doesn't even make sense to say so, because every theory which is random, can be replaced with a theory which is deterministic and which has "hidden variables". So be careful when asking what is "randomness" while thinking about "the laws of nature".

Im aware of this, but lacking enough knowlage to really comment to deeply on it so i omitted it for simplicity.

I apreciate your comments and ill try and reflect on them a bit more.

So maybe your question is: "is nature deterministic" ?

Indeed, that is one of the underlying questions.

 

[pallidin]

I find this discussion rather interesting.
With deterministic theory, there is a demand on value reproducibility. In other words, independent research must exhibit some tangible aspect of reproducible results; else the theory might be considered invalid, undeveloped or even a "sham"(such as supposed "free-energy" devices)

With "randomness", the methodology of verification takes a striking twist:

Randomness can not be "proven" because it is not possible to define exactly what constitutes the difference between randomness-vs-highly convoluted determinism.
A mathematical model for randomness does not exist, nor can it ever exist, as it can not inherently self-validate.

 

[Claude Bile]

On a quantum level, true randomness exists - you can get two different results for the exact same initial conditions. Psuedo-randomness, even chaotic systems do not share this quality.

It is an interesting question, how randomness can exist, but consider the inverse proposition - how can it not exist? In other words, given our apparent freedom of choice, how can the universe be deterministic? While we have yet to reconcile quantum randomness with conscious choice, the mere fact that it opens up the possibility of choice seems to (at least in my opinion) validate the existence of randomness over pure determinism.

Claude.

 

[MeJennifer]

It is an interesting question, how randomness can exist, but consider the inverse proposition - how can it not exist? In other words, given our apparent freedom of choice, how can the universe be deterministic?

You cannot use this as a scientific argument unless you can demonstrate that we have a freedom of choice.

I think it much more plausible that we simply think that we have freedom of choice, but thinking something does not make it so.

 

[Doc Al]

I don't see how randomness can possibly preserve freedom of choice. If something is random, how could you have chosen it?

 

[vanesch]

I don't see how randomness can possibly preserve freedom of choice. If something is random, how could you have chosen it?

Because your choice is random ?
I think the point is that in a deterministic universe, it's clear that there's not such a thing such as freedom of choice (given that everything is already determined since the initial conditions). So the only *hope* to have the *possibility* of a freedom of choice is an element of "randomness", here, of non-determinism : meaning: what happens at an event is not determined by initial conditions of the past.
But it doesn't mean that because there is no temporal determinism, that the random outcome is a result of some free will. It only doesn't forbid it (as determinism does).

 

[Danger]

On a quantum level, true randomness exists - you can get two different results for the exact same initial conditions. Psuedo-randomness, even chaotic systems do not share this quality.

It is an interesting question, how randomness can exist, but consider the inverse proposition - how can it not exist? In other words, given our apparent freedom of choice, how can the universe be deterministic? While we have yet to reconcile quantum randomness with conscious choice, the mere fact that it opens up the possibility of choice seems to (at least in my opinion) validate the existence of randomness over pure determinism.

Claude.

Claude, that is one of the best explanations that I've seen in print.

You cannot use this as a scientific argument unless you can demonstrate that we have a freedom of choice.

I think it much more plausible that we simply think that we have freedom of choice, but thinking something does not make it so.

Despite your claim of atheism in another thread, you certainly seem to take the 'Jesus Freak' approach to things (including in that thread, as evidenced by your hostility toward homosexuality). I'm a true atheist, and therefore 'superdeterminsm' is totally unacceptable. That condition could not exist without a 'supreme being' of whatever denomination. As a side note--Freudian slip?--I just caught that typo in time. My first approach was 'demonination'. Hmmm...

 

[vanesch]

Despite your claim of atheism in another thread, you certainly seem to take the 'Jesus Freak' approach to things (including in that thread, as evidenced by your hostility toward homosexuality). I'm a true atheist, and therefore 'superdeterminsm' is totally unacceptable. That condition could not exist without a 'supreme being' of whatever denomination. As a side note--Freudian slip?--I just caught that typo in time. My first approach was 'demonination'. Hmmm...

Eh, sorry, this has nothing to do with religion. I'd rather say that, if the brain is governed by essentially classical laws (with some noise, which is however not on purpose), there's not much room for free will outside of the laws of nature: what your brain decides is what is determined by these classical laws and the noise (which, I take it, was not "on purpose"). Afterwards, you get the illusion that that is what you "really decided".
Of course, the noise being random, it could be that your "free will" resides in a careful tuning of this at first sight random noise, in order to influence decisions in the right direction. This would then imply that the essence of our brain function doesn't reside in the structure of our brain, but in the thermal noise, which is a strange proposition.
It is only when postulating a soul intervening in the laws of nature that you can really talk about free will.

 

[Danger]

I admit that I've had a few (dozen?) beers, so my debating skills are a bit off. I do submit, however, that any consideration of superdeterminism must of necessity imply the agency of a supreme being. Otherwise, Heisenberg was correct.

 

[vanesch]

I admit that I've had a few (dozen?) beers, so my debating skills are a bit off. I do submit, however, that any consideration of superdeterminism must of necessity emply the agency of a supreme being. Otherwise, Heisenberg was correct.

I fail to see why: the classical, Newtonian universe is entirely deterministic. Where's the superbeing in such a universe ?

 

[Danger]

Newton's work, in fact, was intended to prove the supremacy of his 'maker'. He was a devout Christian, who would gleefully have burned an alleged witch at the stake. Brilliance does not necessarily denote sanity.

 

[vanesch]

Newton's work, in fact, was intended to prove the supremacy of his 'maker'.

Well, that's one of those unfalsifiable claims of course: you can say, if you want, that the laws of nature have a certain "beauty" to them which is an indication of the supremacy (or at least the good taste) of your favorite superbeing. This could very well be. Or not.
The problem with "unfalsifiable" is that it is often equated with "BS", while it isn't. It only indicates that there's no objective way to find out, and that there are things/questions/issues that we, human beings, are not going to know about in an objective and collective way. As such, you're free to claim them, or their opposite, it won't make any observational difference - although it might make a subjective difference to you. So, pick the answers you feel best with (but always remember that it is just a "working hypothesis"). If claiming a superbeing responsible for the laws of nature makes you feel better, feel free to do so. If you'd rather not, feel free to do so too.
The problem with several established religions is not in their unfalsifiable claims ; it is with their falsifiable and falsified claims.

As to free will, for the moment this is still an unfalsified question, but one could think of a way to falsify it: by analysing carefully enough the brain of a person, and predict the 25 next "arbitrary" free will decisions that he will take (like picking out cards of a deck or something). However, if the process turns out to be chaotic or sensitive to external influences, there might be no practical hope to do this, ever. If the brain turns out to be a finite-state machine, then this would be feasible in principle.

 

[Danger]

Okay, this is where I severely regret not having an education. I assume that there must be something wrong with my reasoning, but I can't for the life of me figure out what it is. I'm going on the premise of the Uncertainty Principle, along with Schrodinger's cat. How could there possibly be determinism when the initial conditions can't be known?
Don't feel obliged to respond in a hurry, 'cause I got to get to bed. That last beer just caught me, and I have to go to work in 6 hours. Later, dude.

 

[vanesch]

I'm going on the premise of the Uncertainty Principle, along with Schrodinger's cat. How could there possibly be determinism when the initial conditions can't be known?

That's why I said that in a quantum universe, there might be some form of irreducible randomness. Might be. Because, in a Bohmian view on things for instance, the randomness *still* comes about from our lack of knowledge of initial conditions, and not from any non-determinism in the laws of nature, exactly as in Newtonian physics. The initial conditions determine still, deterministically, every event that will occur in the future. The fact that this knowledge of initial conditions is partially hidden from us (in the sense that we cannot find any operational means to find them out beyond a certain accuracy) has nothing to do with whether nature is deterministic or not. For instance, it is not because you do not know or understand a certain mathematical proof, that the theorem is not valid. Truth has not much to do with what you can know about it, and a particle in a Bohmian universe, which *has* a precise position (even though you don't know it precisely) will deterministically go there and not here (even though you can't predict this, given your lack of knowledge from the start).

So it is very difficult, if not impossible, to find out whether observed randomness is irreducible and non-deterministic randomness, or whether this is just a lack of knowledge on our part.
Free will is very similar.

 

[MeJennifer]

Despite your claim of atheism in another thread, you certainly seem to take the 'Jesus Freak' approach to things (including in that thread, as evidenced by your hostility toward homosexuality). I'm a true atheist, and therefore 'superdeterminsm' is totally unacceptable. That condition could not exist without a 'supreme being' of whatever denomination. As a side note--Freudian slip?--I just caught that typo in time. My first approach was 'demonination'. Hmmm...

Sorry but I do not follow you at all. The "Jesus Freak" approach?

By the way "hostility towards homosexuality"? I have no idea what you are talking about.
I have no opinion about someone's sexual preferences. Frankly I don't care, it is none of my business.

Anyway all this is entirely irrelevant to the topic at hand.

 

[moving finger]

Okay, this is where I severely regret not having an education. I assume that there must be something wrong with my reasoning, but I can't for the life of me figure out what it is. I'm going on the premise of the Uncertainty Principle, along with Schrodinger's cat. How could there possibly be determinism when the initial conditions can't be known?
Don't feel obliged to respond in a hurry, 'cause I got to get to bed. That last beer just caught me, and I have to go to work in 6 hours. Later, dude.

As Vanesch points out - Be careful not to confuse ontic indeterminism with epistemic indeterminability. Here is a good explanation of the difference :

http://philsci-archive.pitt.edu/archive/00000939/00/determ.pdf

The HUP says that there are fundamental limits to our knowledge about the world (epistemic determinability). It does NOT say that there are any limits to ontic determinism (the way the world really is).

Thus the answer to your question "Is the world really random or not?" lies forever on the other side of that epistemic horizon - inaccessible to us.

Best Regards

ps - the analogy with free will suggested by Vanesch I do not agree with. We can construct coherent, rational and logical models of the world that are either deterministic or not; but I'm not aware of a coherent, rational and logical model of the world that is based on the notion of free will.

 

[vanesch]

Sorry but I do not follow you at all. The "Jesus Freak" approach?

By the way "hostility towards homosexuality"? I have no idea what you are talking about.
I have no opinion about someone's sexual preferences. Frankly I don't care, it is none of my business.

Anyway all this is entirely irrelevant to the topic at hand.

I agree with that ; let us not pollute the thread here with some issues in the general discussion forum. (this is the mentor "vanesch" speaking not the physicist).

 

[vanesch]

ps - the analogy with free will suggested by Vanesch I do not agree with. We can construct coherent, rational and logical models of the world that are either deterministic or not; but I'm not aware of a coherent, rational and logical model of the world that is based on the notion of free will.

I guess you're right. There's more need for spirituality in the notion of free will than in the ontic notion of determinism or not. The problem with free will is that "something" has to have it, and clearly that something cannot be physical because it would otherwise just obey physical laws as anything else and hence not have the will in the first place. So this would be something, by definition, not open to rational and logical analysis.

I think the only point we can really make, is that ontic determinism excludes any notion of free will (apart from the *illusion* of free will of course). Non-deterministic views ALLOW potentially free will, in that there is still some "room to manoeuver", but certainly do not imply it.

That said, even the more spiritual notions of free will are still a far cry from any necessity of a creator or anything of the kind, in the same way as the absence of free will, or strict determinism, does not imply either way the existence or not of any creator (who could have "written down the laws of nature" and "the initial conditions" to his/her/its will or not).
All these notions are so far outside of the scope of science that no scientific statements have any implication on it.

 

[vanesch]

As Vanesch points out - Be careful not to confuse ontic indeterminism with epistemic indeterminability. Here is a good explanation of the difference :

http://philsci-archive.pitt.edu/archive/00000939/00/determ.pdf

Brilliant paper ! Highly recommended (although there's a part of maths that escapes me a bit in the middle - just skip it).

 

[Hans de Vries]

It is an interesting question, how randomness can exist, but consider the inverse proposition - how can it not exist? In other words, given our apparent freedom of choice, how can the universe be deterministic? While we have yet to reconcile quantum randomness with conscious choice, the mere fact that it opens up the possibility of choice seems to (at least in my opinion) validate the existence of randomness over pure determinism.
Claude.

There doesn't seem to be any contradiction between "free choice" and determinism.

It's just that somebody's choices become predictable... Regards, Hans

 

[moving finger]

I think the only point we can really make, is that ontic determinism excludes any notion of free will (apart from the *illusion* of free will of course). Non-deterministic views ALLOW potentially free will, in that there is still some "room to manoeuver", but certainly do not imply it.

I'm not sure that the idea of free will is in any way coherent.

If free will exists, then surely we want our actions to be determined by our will? How could we claim responsibility for our actions otherwise, and what would be the purpose of introducing non-determinism into our actions following our free will decision? Thus it would seem we do need determinism on the "downstream" side, ie the physical consequences of our free will decisions must surely be deterministic?

Where, then, would we want to introduce any non-determinism into the entire process? Surely our free will choices themselves are not supposed to be "random"? How about introducing some non-determinism prior to our free will choice perhaps? But how could that work, and still be rational?

Any way you dissect it, it just doesn't make rational sense.

Best Regards

 

[vanesch]

If free will exists, then surely we want our actions to be determined by our will? How could we claim responsibility for our actions otherwise, and what would be the purpose of introducing non-determinism into our actions following our free will decision? Thus it would seem we do need determinism on the "downstream" side, ie the physical consequences of our free will decisions must surely be deterministic?

Well, the "free" part would indicate that you have a choice, which you don't have if the event on which you're going to decide is already determined for at least 15 billion years. It is a bit as if you are claiming to have a free decision of the trajectory of a train. You don't. It follows the track. Now, you can come back and claim that the track exactly goes where you will decide to go, but there's not much free will when there are no alternatives.
The "randomness" means simply that there are alternatives. It means that the laws of nature alone do not fix uniquely the event to be decided, but leave several alternatives, of which you (outside of the laws of nature) can then pick one. That's then your "free choice". In order to be able to chose, you need at least 2 alternatives, right ?

Where, then, would we want to introduce any non-determinism into the entire process? Surely our free will choices themselves are not supposed to be "random"? How about introducing some non-determinism prior to our free will choice perhaps? But how could that work, and still be rational?

Well, it can only be "rational" if you accept a non-physical intervention into physical happenings (a kind of soul or something). The randomness should then be on the side of the purely physical, so that the choice between different possible alternatives is not in contradiction with the laws of nature. So nature (and its physical laws) need to leave some "room for decision" and hence need to leave "alternative possible events from which to choose", which is not the case for an ontic determinism, where the event that's going to happen is unique and determined since the very beginning.

 

[vanesch]

It's just that somebody's choices become predictable...

There's not much freedom in it, then, is there ?