Does randomness exist?

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  • #51
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As I understand the question it is not

Is everything random?

but

Is anything random?

The second does not preclude the option of some things some being random and some nonrandom.

You only need to point to one randon event to answer yes to the question, no matter how many non random events you can catalogue.

My offering presented a way of working with any randomness more precisely.

Have a nice day.
 
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  • #52
fluidistic
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As individual beings, we know what we're going to do next, the people who know us extremely well MAY be able to predict this, to a limited degree
I completely disagree with this. There are random processes occurring in the brain which can be described by quantum mechanics. We do not have a control over it and hence we don't know what we'll do. Rather we could know what we will likely do.
Here is an article (http://www.scientificblogging.com/news_articles/other_people_know_you_better_you_do_study_shows) that shows that others know us better than we do, for some of our characteristics. Hence others can predict better some of our reactions to situations than we do.
I don't know enough quantum mechanics nor did I read the whole thread, but I believe it's generally assumed that a true randomness (i.e. something totally unpredictable, even knowing the maximum amount of information) exists in this theory. Until now, this theory hasn't been showed wrong in its range of accuracy.
 
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  • #53
I completely disagree with this. There are random processes occurring in the brain which can be described by quantum mechanics. We do not have a control over it and hence we don't know what we'll do. Rather we could know what we will likely do.
Here is an article (http://www.scientificblogging.com/news_articles/other_people_know_you_better_you_do_study_shows) that shows that others know us better than we do, for some of our characteristics. Hence others can predict better some of our reactions to situations than we do.
I don't know enough quantum mechanics nor did I read the whole thread, but I believe it's generally assumed that a true randomness (i.e. something totally unpredictable, even knowing the maximum amount of information) exists in this theory. Until now, this theory hasn't been showed wrong in its range of accuracy.
Dear fluidistic, your next decision is yours alone. You have COMPLETE knowledge of what it is, because you do it (I am talking about your IMMEDIATE next action). I'm not talking about anything outside of what you do. It's foundation is your desire and your state of understanding at that time. I'm not talking about you knowing why you have those desires. I don't even know if that'll ever be an important question.

Of course quantum formulae are useful in predicting a range of possible outcomes. Some take this as proof that randomness exists in reality. It does not prove that, and never can. I could produce a probablistic formula for any number of unknowns, and this would be backed up 100% by experimental data, because of course, the probablistic formula does not predict a precise outcome in the first place, just a range. The next question is, then, do we dare or bother to ask WHY a certain outcome happens rather than another outcome, or at least admit that we don't know the reason? Or, do we take a brazen leap of faith and assign a new force we call "randomness", which has zero foundation in logic. The second option closes that "why" question forever. Do we have any reason whatsoever to be that brazen about it? Of course if we are we've already stopped asking why, so scientific progress in that area is halted completely and forever (and only because of a leap of faith in something with no logical foundation!). Scientists should not take such unnecessary leaps of faith for no good reason.
 
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  • #54
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We can only ever describe our observations. We cannot address ontological truth in any tangible way. I can only say that certain things appear random. Similarly, I can state that certain relationships permit a deterministic description. However, this determinism is a property of the description I have constructed, not necessarily of reality itself. You cannot prove determinism any more than you can prove randomness (you can only observe that certain events have arbitrarily high levels of correlation with each other).
 
  • #55
fluidistic
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Dear fluidistic, your next decision is yours alone. You have COMPLETE knowledge of what it is, because you do it (I am talking about your IMMEDIATE next action). I'm not talking about anything outside of what you do.
Hi Navigateur, I share a different viewpoint. However I agree that if you've done something on purpose, i.e. knowing that you would do it, then yes you had the control over yourself and the decision was yours. But it is not always the case. What if my next action is an involuntary movement? What if it was caused by a quantum effect of say a flow of electrons in the brain or whatever? It was my next action, however I didn't control it nor was it my decision to move.


Navigateur said:
It's foundation is your desire and your state of understanding at that time. I'm not talking about you knowing why you have those desires. I don't know if we'll ever even need to know that.
In the case of involuntary movement, this is false.

Navigateur said:
Of course quantum formulae are useful in predicting a range of possible outcomes. Some take this as proof that randomness exists in reality. It does not prove that, and never can.
Why do you say it's not a proof? I don't know if you know French (since your nickname is a French word), in the affirmative case, I strongly suggest you to listen to a small part of an interview of Étienne Klein. He's a physicist with an important post in France and he also has a Ph.D. in philosophy, earning a special mention for his thesis. See http://www.arte.tv/fr/science/104012,CmC=1551806,CmPart=com.arte-tv.www.html [Broken]. He has a different point of view than yours about quantum mechanics. I've seen the interview more than a year ago so I may misquote him, but he basically said that throwing dices was not a true randomness because if you knew the initial conditions to an extreme degree, you'd know the outcome. He then says that things are different in QM and that one can NEVER know the "initial conditions" (for example the position and the velocity of a particle) not because they're hidden, but because they don't exist if no measurement is done (they can't exist both at the same time with a perfect accuracy). I remember him clearly saying that there is a "true randomness" in QM, unlike in Classical Mechanics. I'm just a second year physics student so I don't have his knowledge on both physics and philosophy, but I must say he's quite convincing.


Navigateur said:
I could produce a probablistic formula for any number of unknowns, and this would be backed up 100% by experimental data, because of course, the probablistic formula does not predict a precise outcome in the first place, just a range. The next question is, then, do we dare or bother to ask WHY a certain outcome happens rather than another outcome, or at least admit that we don't know the reason? Or, do we take a brazen leap of faith and assign a new force we call "randomness", which has zero foundation in logic.
What do you mean by "zero foundation in logic"? If I understand well the meaning, why an impossibility to know the outcome of a very simple experiment is illogic? Why do you assume that it's possible to know every initial configuration? In classical mechanics I agree it's possible, but not in QM. Now why trust QM? As I said, it hasn't been showed
wrong in its range of accuracy. I've read in a scientific website saying that there's a new article saying that any other theory that would replace QM cannot have more determinism than QM. In other words (I'm not expressing myself well in English), any other theory that would pretend to replace QM would have to have at least the same amount of indeterminism than the one of QM. It really implies that it's impossible to know "all velocities and positions of all particles at the same time". If anyone has the reference of the article, I'd be glad to know it. It stated that Einstein was wrong by thinking that eventually a more general theory than QM used to describe the microscopic world would be deterministic. It stated that Bohr was in the right direction with his QM and that there is no doubt today about it.
I also remember (from when I was 15 or 16, I'm 22 now) Brian Greene saying that Laplace's determinism has been eradicated by QM, in his famous "The elegant Universe".
Now, I'd love to hear some physicists on the subject.
Ah, and what is the relation between determinism and randomness? I believe that the indeterminism of QM leads to a pure randomness, i.e. some events whose outcomes are impossible to predict, no matter what theory you're using or if you know the maximum number of variable possible (which is less than all, according to QM and any other theory that pretend to replace it).
 
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  • #56
he basically said that throwing dices was not a true randomness because if you knew the initial conditions to an extreme degree, you'd know the outcome. He then says that things are different in QM and that one can NEVER know the "initial conditions" (for example the position and the velocity of a particle) not because they're hidden, but because they don't exist if no measurement is done (they can't exist both at the same time with a perfect accuracy). I remember him clearly saying that there is a "true randomness" in QM, unlike in Classical Mechanics. I'm just a second year physics student so I don't have his knowledge on both physics and philosophy, but I must say he's quite convincing.


What do you mean by "zero foundation in logic"? If I understand well the meaning, why an impossibility to know the outcome of a very simple experiment is illogic? Why do you assume that it's possible to know every initial configuration? In classical mechanics I agree it's possible, but not in QM. Now why trust QM? As I said, it hasn't been showed
wrong in its range of accuracy. I've read in a scientific website saying that there's a new article saying that any other theory that would replace QM cannot have more determinism than QM. In other words (I'm not expressing myself well in English), any other theory that would pretend to replace QM would have to have at least the same amount of indeterminism than the one of QM. It really implies that it's impossible to know "all velocities and positions of all particles at the same time". If anyone has the reference of the article, I'd be glad to know it. It stated that Einstein was wrong by thinking that eventually a more general theory than QM used to describe the microscopic world would be deterministic. It stated that Bohr was in the right direction with his QM and that there is no doubt today about it.
I also remember (from when I was 15 or 16, I'm 22 now) Brian Greene saying that Laplace's determinism has been eradicated by QM, in his famous "The elegant Universe".
Now, I'd love to hear some physicists on the subject.
Ah, and what is the relation between determinism and randomness? I believe that the indeterminism of QM leads to a pure randomness, i.e. some events whose outcomes are impossible to predict, no matter what theory you're using or if you know the maximum number of variable possible (which is less than all, according to QM and any other theory that pretend to replace it).

Dear fluidistic, you said "Now why trust QM? As I said, it hasn't been showed
wrong in its range of accuracy". That is the fundamental crux of your comment. And I point you again to the fact that I agree that its range of accuracy is shown to be right, and always will be, and I could produce a probablistic formula for any number of unknowns I like, it doesn't prove anything. It just shows that I don't know the reason for the variations. Can you come up with a more substantial defence than that? Well, it doesn't exist, and I'll tell you why.

You mentioned the uncertainty principle, but that was never about past events, Heisenberg was clear that in past events, particles CAN have had any-degree accurately measured position and momentum (quote from Heisenberg: "the uncertainty relation does not hold for the past"), so it was about CURRENT POSITION AND TRAJECTORY, in other words, his statements are about a very simple and blindingly obvious aspect of our observations, namely the particle's (from "now onwards") apparent "UNPREDICTABILITY" in behaviour!
So I ask you, not as a physicist, but as a human being, does the idea of "a particle's true state doesn't exist until I measure it", or "a particle is in infinite simultaneous states at a given time, one for each of the infinite parallel universes" or any of those other such made statements actually make sense to you? Can they be founded in logic? If, as it should be, the answer is obvious to you, then those statements are simply extremely guarded and convoluted ways of saying "I HAVE NO IDEA WHY THIS IS HAPPENING!" (as a natural result of the observed apparently unpredictable behaviour of the particles!) and nothing else. Why can't they just admit it like this? Because everybody likes to think they're better than Einstein, it makes them feel good. But science is not about outlandish leaps of faith such as those. It is about logic.

There's nothing wrong with not knowing why something is happening. I never suggested that we would be able to derive a maths formula for particle behaviour. We may never understand it. Just like human behaviour would be difficult to decipher by a maths formula by a "non-human" observer. But let's at least have the balls to admit it. And let's not make silly leaps of faith to compensate for this lack of balls.
 
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  • #57
fluidistic
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Dear fluidistic, you said "Now why trust QM? As I said, it hasn't been showed
wrong in its range of accuracy". That is the fundamental crux of your comment. And I point you again to the fact that I agree that its range of accuracy is shown to be right, and always will be, and I could produce a probablistic formula for any number of unknowns I like, it doesn't prove anything. It just shows that I don't know the reason for the variations. Can you come up with a more substantial defence than that? Well, it doesn't exist, and I'll tell you why.

You mentioned the uncertainty principle, but that was never about past events, Heisenberg was clear that in past events, particles CAN have had any-degree accurately measured position and momentum (quote from Heisenberg: "the uncertainty relation does not hold for the past"), so it was about CURRENT POSITION AND TRAJECTORY, i.e. his statements are about a very simple and blindingly obvious aspect of our observations, namely the particle's (from "now onwards") apparent "UNPREDICTABILITY" in behaviour.
So I ask you, not as a physicist, but as a human being, does the idea of "a particle's true state doesn't exist until I measure it", or "a particle is in infinite simultaneous states at a given time, one for each of the infinite parallel universes" or any of those other such made statements actually make sense to you? Can they be founded in logic? If, as it should be, the answer is obvious to you, then those statements are simply extremely guarded and convoluted ways of saying "I DON'T KNOW WHY THIS IS HAPPENING" ("this" meaning the observed apparently unpredictable behaviour of particles) and nothing else. Why can't they just admit it like this? Because everybody likes to think they're better than Einstein, it makes them feel good. But science is not about outlandish leaps of faith such as those. It is about logic.

There's nothing wrong with not knowing why something is happening. I never suggested that we would be able to derive a maths formula for particle behaviour. We may never understand it. Just like human behaviour would be difficult to decipher by a maths formula by a "non-human" observer. But let's at least have the balls to admit it. And let's not make silly leaps of faith to compensate for this lack of balls.
There are results in QM that are either '0' or '1'. For example measuring a property of the electron (I don't remember what property). QM states that both outcomes have exactly the same probability to occur, namely 1/2. A physicist that make the measurement will never ask himself "why was the outcome 1 and not 0?" as you seem to imply in your last post. I know no physicist that thinks he's "better than Einstein" although maybe there are some. Crackpots may believe so.
There were more than one recent experiments that tried to determine whether the photon was a wave or a particle, before a measurement could be done. The surprising answer was that it wasn't a particle nor a wave before the measurement was done. We've succeeded in "trapping" the photon to know its "true" property but we've learned that there is no such thing as a true property, i.e. if it is a wave or a particle before you measure it. This completely goes against your intuition because our intuition is based on the macroscopic universe's behaviour, or an intuition very close to classical mechanics. Now saying, as you seem to believe, that the universe behaves like classical mechanics for a "non-human" observer, call it God or whatever, will never be in agreement with QM. Not being in agreement with QM means a false theory, or a theory that cannot describe the microscopic world. I repeat myself, but any theory that pretend to be more general than QM has to be in agreement with it, at least. It's a necessity. Physicists has shown this.
I'm leaving the conversation, I just hope a physicist will come and definitely put the last word on this "debate".
By the way, think about it: You seem really convinced that the world is deterministic, not for us humans because of your limitation, but for a non-human observer. You go against Bohr, QM, Klein, B.Greene and more than 90% of today's physicists I'd say. Philosophy alone cannot solve this problem; unfortunately you need measurements and theories trying to explain the outcomes of these measurements. QM has done its job perfectly until now. QM implies that the world is not deterministic and thus that randomness exists. No matter who you are (God, a cat, a human, etc.). I'm done with this discussion.
 
  • #58
You have said much of nothing just now.

The ONLY observed empirical data for quantum-level behaviour is apparently unpredictable behaviour. Nothing else. Quantum mechanics has never NEEDED anything more to "DO IT'S JOB PERFECTLY".

The leaps of faith remind me of belief in God. People were not satisfied that they could not explain the world (it didn't seem to make sense), so they created the illogical concept "God" as explanation. And this was a hindrance to science. In the same way, people were not satisfied that they could not explain quantum-level behaviour (it didn't seem to make sense), so they created illogical concepts such as "randomness", "the observer effect" and others as explanation. In the same way, these are hindrances to science.

This is more about ego than anything else.

I'm done with this discussion.
A sure sign you have nothing to say.
 
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  • #59
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I belive in determinism to a certain extent, there are specific occurences which i belive cant be predicted, but that there is an overall pattern in the universe cannot be argued. Maybe its like rolling a fair die, you cant know what it will be, but you do know that if you repeat the throw an infinite number of times, roughly one sixth of the time it will be 1.
 
  • #60
155
1
I'm gona have to agree with navigateur QM does infact seem to be to science as to what god is to spirituality.

The only way I can see randomness existing is if "uncaused" causes can exist. As far as I can tell they can not and the work around to that is if an effect can be a cause to the cause.
 
  • #61
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Free-will is a by-product of limited and relative awareness, such as ours.

A being (aka God), would, paradoxily so, have no free-will, since it would always know the best choice (if He had to chose as we do).

Randomness is thus similar to free-will in sense that it has true appearance due to limited and relative information.

Cellular automata is a beautiful example of VERY simple rules producing 'random' patterns. Wolfram uses it in his program Mathematica - check it out.
 
  • #62
chiro
Science Advisor
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This is a great thread and I thank the OP for starting it.

My personal view is that randomness is used to describe "unknown complexity". Consider that any process of some sort can be represented in any system (ie analytic, differential, partial differential etc). If we can model every system that is possible, then intuitively we would expect that there exists a unique representation for any system that is deterministic.

I'm going to go for a long shot and predict that the mathematics that is available in the next few centuries will see unifying factors between analysis and probability that help turn distributions into DE's or PDE's and not use simple linear models to describe the relationship between variables.

Also I imagine people will come up with more ways to essentially decompose mathematical processes which essentially shapes how we analyze things and how we understand things at different "atomic" viewpoints.

Personally I don't believe true randomness exists and my argument for that is based on my belief that every possible system with any amount of variables can be modeled using current mathematics to give a unique system that is dependent upon the relationships of the system and upon conditions of the system at given points. Its obviously not a trivial thing to prove (and my mathematical maturity is lacking in order to do so) but yeah if we consider all processes that are continuous then there must exist a function representation to describe the very process.
 
  • #63
"Statistical" randomness can exist. But "True" randomness as some have stated is logically contradictory. What one implies with it is acausality, that identical conditions or premises(down to the most basic level) will yield at least two or more different outcomes which can even be contradictory to the other possible outcomes.

Acausality can exist in terms of the existence of truths being atemporal, without cause, but it cannot exist within said truths. The starting premises or conditions cannot yield different and possibly even opposing conclusions that contradict each other(This only occurs in human arguments, because there exist unstated assumptions that change the conclusion derived from the data... but if we were given all the assumptions, which are additional premises, the conclusion would be one.).

When it comes to the past we do not say that there are probabilities, there are only certainties. We say the probability becomes 100% after the fact, but this implies that there is a qualitative division between past, present and future. If we assume no qualitative difference exists between past, present and future, we must assume that both the present and the future are as determined as the past, and thus are https://www.physicsforums.com/showpost.php?p=2384967&postcount=24".

PS

As for quantum uncertainty, besides the hidden variables very real possibility. I've heard( in some articles) that it is theoretically possible , using some of the same quantum unintuitive phenomena, to device a method that can have some probability of detecting some aspects of something without disturbing it at all( quantum-mechanics interaction free measurements). If this is not false , it would suggest to me that even though it is a very low probability if similar methods exists(that have not been discovered) that allow measurements of other aspects without disturbing, it could be possible to measure multiple aspects of something at the same time and get a result without disturbing it.

The only thing that would impede this would be that the first premise is false(this type of measurement is impossible), or the second one(there exists no way to measure other aspects in this way).


PPS

Another example would be that of pseudorandom number generation, just like pseudorandom numbers any sequence that lies in the past becomes predictable if it reoccurs in the future. Thus it is no longer unpredictable. If we assume the future and present are qualitatively no different than the past, we see that it too must be as solid and as determined. But not only that there will, given infinite time, always exists an infinity of future observers, such that all possible finite sequences lie in the past relative to some future observer, and thus are all in principle predictable.

The only way this would not be is if time is not infinite or the future and present are qualitatively different from the past. Then we'd need a mechanism that transitions and qualitatively changes states from future to present to past. What mechanism could this be? And what would it be doing, creating the present based on the past? Choosing amongst parallel possible futures? What would it be doing?, and how could it operate?, as this mechanism must be truly random it would have to be intrinsically so and it would also have to deal with the fact that time passes at different rates for different observers yet we all share the same causal world.
 
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