Is there inherent, observable randomness in the universe?

[Darryl_P]

Before you tell me that Quantum Mechanics says there is, consider this:

The only way we can know about a particle's position is via our senses, the most appropriate of which is vision. For our eyes to detect something we need photons to transmit information.

In the case of particles on a small scale similar to photons it stands to reason that the ability of photons to transmit reliable information is restricted, just as you could not get a very accurate picture on your TV screen or digital camera if it only used 1 or 2 pixels instead of several million.

It is my understanding that this limitation of photons' ability to transmit information is the key to the uncertainty principle, and therefore what seems like inherent randomness in the universe really isn't. The particle is there, only we can never know for sure, no matter how accurate our measuring devices become. The limitation applies to us and not the universe.

Just as Sklansky is looking for evidence to support the existence of God via his threads on miracles, I am looking for evidence to support atheism ie. that randomness actually exists in the observable universe and not just in our minds.

I currently am a believer in God, but if I see convincing evidence about the above, then I would seriously begin considering atheism. Any help, info., links, etc. would be greatly appreciated.

[DougShrapnel]

Do I get any points if I where to demostrate that the universe itself is arbitrary?

[bluesbassman]

[ QUOTE ]
Before you tell me that Quantum Mechanics says there is, consider this:

The only way we can know about a particle's position is via our senses, the most appropriate of which is vision. For our eyes to detect something we need photons to transmit information.

In the case of particles on a small scale similar to photons it stands to reason that the ability of photons to transmit reliable information is restricted, just as you could not get a very accurate picture on your TV screen or digital camera if it only used 1 or 2 pixels instead of several million.

It is my understanding that this limitation of photons' ability to transmit information is the key to the uncertainty principle, and therefore what seems like inherent randomness in the universe really isn't. The particle is there, only we can never know for sure, no matter how accurate our measuring devices become. The limitation applies to us and not the universe.


[/ QUOTE ]

This interpretion of the uncertainty principle is incorrect. Randomness is a fundamental, inherent property of the universe, rather than a practical limitation on measurement devices. Here is a Wilkpedia link which explains exactly that:

Uncertainty Principle

[ QUOTE ]

Just as Sklansky is looking for evidence to support the existence of God via his threads on miracles, I am looking for evidence to support atheism ie. that randomness actually exists in the observable universe and not just in our minds.

I currently am a believer in God, but if I see convincing evidence about the above, then I would seriously begin considering atheism. Any help, info., links, etc. would be greatly appreciated.

[/ QUOTE ]

Read the link I already provided. To the best of our knowledge, the universe is inherently nondeterministic. Accept it.

Regardless, whether the physical laws are ultimately deterministic or nondeterministic has nothing at all to do with whether "god" exists. Presumably, this "god" could have "designed" the universe to be nondeterministic. (In fact, some theists argue precisely that to rectify the contradiction between on omniscient god and free will.)

I'm an atheist not because of the uncertainty principle, but rather because the concept of "god" is arbitrary and meaningless.

[ QUOTE ]
The particle is there, only we can never know for sure, no matter how accurate our measuring devices become. The limitation applies to us and not the universe.

[/ QUOTE ]

I'm afraid you don't fully understand the results of the double slit experiment with single particles.

from http://www.space.com/searchforlife/q...y_041111.html:

"So light is both a particle and a wave. OK, kind of unexpected (like Jell-O) but perhaps not totally weird. But the double slit experiment had another trick up its sleeve. One could send one photon (or “quantum” of energy) through a single slit at a time, with a sufficiently long interval in between, and eventually a spot builds up that looks just like the one produced when a very intense (many photons) light was sent through the slit. But then a strange thing happened. When one sends a single photon at a time (waiting between each laser pulse, for example) toward the screen when both slits are open, rather than two spots eventually building up opposite the two slit openings, what eventually builds up is the interference pattern of alternating bright and dark lines! Hmm… how can this be, if only one photon was sent through the apparatus at a time?

The answer is that each individual photon must – in order to have produced an interference pattern -- have gone through both slits! This, the simplest of quantum weirdness experiments, has been the basis of many of the unintuitive interpretations of quantum physics. We can see, perhaps, how physicists might conclude, for example, that a particle of light is not a particle until it is measured at the screen. It turns out that the particle of light is rather a wave before it is measured. But it is not a wave in the ocean-wave sense. It is not a wave of matter but rather, it turns out that it is apparently a wave of probability. That is, the elementary particles making up the trees, people, and planets -- what we see around us -- are apparently just distributions of likelihood until they are measured (that is, measured or observed). So much for the Victorian view of solid matter!"

This uncertainty isn't really a limitation due to our ability to measure precisely, but instead, until measured, the particle is in effect ("physically") everywhere at once (distributed according to its probability function). There has been no neat explanation of how this can be, only quantification of the consequences. To explain this behavior in a manner that humans can understand will (I believe) require a fundamental breaking down of everything we think we "know" about matter and the universe, on a scale that surpasses even relativity in its "weirdness". Bottomline is the universe is far more "strange" than we can fully understand right now -- but we have the tools to quantify and predict its behavior on a probability basis! (This doesn't necessitate "randomness", either, however. It could be deterministic based on causes we cannot observe at this time, like vibrations in another dimension for example.)

[Trantor]

[ QUOTE ]
Before you tell me that Quantum Mechanics says there is, consider this:

The only way we can know about a particle's position is via our senses, the most appropriate of which is vision. For our eyes to detect something we need photons to transmit information.

In the case of particles on a small scale similar to photons it stands to reason that the ability of photons to transmit reliable information is restricted, just as you could not get a very accurate picture on your TV screen or digital camera if it only used 1 or 2 pixels instead of several million.

It is my understanding that this limitation of photons' ability to transmit information is the key to the uncertainty principle, and therefore what seems like inherent randomness in the universe really isn't. The particle is there, only we can never know for sure, no matter how accurate our measuring devices become. The limitation applies to us and not the universe.

Just as Sklansky is looking for evidence to support the existence of God via his threads on miracles, I am looking for evidence to support atheism ie. that randomness actually exists in the observable universe and not just in our minds.

I currently am a believer in God, but if I see convincing evidence about the above, then I would seriously begin considering atheism. Any help, info., links, etc. would be greatly appreciated.

[/ QUOTE ]
Even as a "devout" atheist I would not say that proof of randomness in the universe would be a grounds for denying the existance of a God.

As a physicist I offer the following brief comments.

The inherent randomness of the universe exhibits itself at small scales where the most appropriate observational tool is most defiitely not the eye. When did you last see an atom?


The photon / uncertainty example you mention is a a sort of classical explanation of Heisenburg's uncertainty principle i respect of the double slit experiment but the uncertainty principle is not a result of this sort of observational interaction.

As to quantum mechanics, I'm afraid I have to refer to this as this is the explanation of how things are. It is inherent in this theory, the randomness you talk about. No test to date has disproved quantum mechanics and the inherent "randomness" of aspects of the theory.

Quantum electrodynamics, in particular, is the most accurate theory known to man at the present time.

The thhing to bear in mind is that uncertainty of quantum mechanics does not arise from the paucity of the measurement apparatus but is a fundamental of the theory (as understood today). There are efforts to remove the randomness by hidden variable theory but there is no demonstration that this view is correct.

So, the universe as presently understood appears inherently random in certain aspects, ie in regimes where quantum mechanics applies.

[kevyk]

Before the late 1960's, there were in fact two competing interpratations of the Heisenberg uncertainty principle. The 'realist' school believed, as you do, that a particle does have a definite position and momentum, but that they are unknowable (or at least not predicted by quantum theory). The competing 'Copenhagen' interpretation, which has become the accepted one, holds that a particle does not have a definite position or momentum until a measurement is taken.

Believe it or not, this is a testable proposition. In 1965, John Bell proposed an experiment to rule the "hidden variable theory" in or out. Wikipedia explains here and here.

Repeated experiments have shown that the universe violates Bell's inequality and therefore does exhibit randomness.

[Darryl_P]

I am familiar with the double slit experiment, or at least the key point it makes about a particle having to go through both at once, and it is very interesing indeed, but as you said in your last few lines, I don't see how it proves inherent randomness since there could theoretically be a host of explanations involving knowledge we don't have yet, not all of which involve inherent randomness.

Instead I see humans invoking prob+stats the same way they do for everything else, ie. to give at least partial explanations for something they don't have full explanations for -- which is very good indeed and much better than nothing IMO.

[chezlaw]

[ QUOTE ]
Before the late 1960's, there were in fact two competing interpratations of the Heisenberg uncertainty principle. The 'realist' school believed, as you do, that a particle does have a definite position and momentum, but that they are unknowable (or at least not predicted by quantum theory). The competing 'Copenhagen' interpretation, which has become the accepted one, holds that a particle does not have a definite position or momentum until a measurement is taken.

Believe it or not, this is a testable proposition. In 1965, John Bell proposed an experiment to rule the "hidden variable theory" in or out. Wikipedia explains here and here.

Repeated experiments have shown that the universe violates Bell's inequality and therefore does exhibit randomness.

[/ QUOTE ]
I'm not an expert but as I understand it Bell inequality is an attempt to show that there are random phenomena or the speed of light can be exceded.

Even if Bells test is passed (failed?) to any precision it could be that the speed limit is high enough to maintain deterministism in a way that conforms with relativity.

Imagine a computer simulation that runs much faster than the speed of light but simulates a universe with the speed of light constant as per relativity. QM could be a window into the nature of the simulation rather than evidence of randomness. [models could then be created that don't require a computer simulation].

This could all be rubbish.

chez

[Darryl_P]

[ QUOTE ]
When did you last see an atom?


[/ QUOTE ]

OK you have a point there. I suppose I should have said we use measuring instruments which need light to transmit the information much like our eyes do, as opposed to our other sensory organs. Or is this not true either?

[ QUOTE ]
There are efforts to remove the randomness by hidden variable theory but there is no demonstration that this view is correct.


[/ QUOTE ]

So you are saying that a minority of physicists believe there is an underlying deterministic process behind the uncertainty principle?

Is it safe to say, then, that inherent randomness of the universe has not been *proven* (at least to the extent that something can be proven in physics), even though it is widely (but not unanimously) believed among leading physicists?

[Darryl_P]

[ QUOTE ]
Repeated experiments have shown that the universe violates Bell's inequality and therefore does exhibit randomness.

[/ QUOTE ]

According to Trantor's post above it seems some physicists are still working on a hidden variable theory. I wonder why they weren't convinced!?

Based on all the responses so far I've clicked on some of your links and done some digging myself and I found a couple of interesting things:

1) A poll of 72 leading physicists conducted by the American researcher David Raub in 1995 and published in the French periodical Sciences et Avenir in January 1998 recorded the following results:

Yes, I think MWI is true 58%
No, I don't accept MWI 18%
Maybe it's true but I'm not yet convinced 13%
I have no opinion one way or the other 11%
link

2) Q13 Is many-worlds a deterministic theory?
Yes, many-worlds is a deterministic theory, since the wavefunction obeys a deterministic wave equation at all times. All possible outcomes of a measurement or interaction (See "What is a measurement?") are embedded within the universal wavefunction although each observer, split by each observation, is only aware of single outcomes due to the linearity of the wave equation. The world appears indeterministic, with the usual probabilistic collapse of the wavefunction, but at the objective level, which includes all outcomes, determinism is restored.
Some people are under the impression that the only motivation for many- worlds is a desire to return to a deterministic theory of physics. This is not true. As Everett pointed out, the objection with the standard Copenhagen interpretation is not the indeterminism per se, but that indeterminism occurs only with the intervention of an observer, when the wavefunction collapses. (See "What is the Copenhagen interpretation?")
link

So the many-worlds interpretation, which is in contradiction with the Copenhagen interpretation, looks like it's widely believed among leading physicists. If it's the correct one, then QM is a lot of things, but it's not evidence of inherent randomness in the universe.