Randomness

Mazuz

What I'm actually trying to argue is that both viewpoints are equally speculation, QM does not show evidence one way or another for natures deepest properties. QM has shown a way of making accurate predictions using probability at a certain level, that is all it can claim to say. If QM was a theory of everything it may be able to say something inherent about the universe at large, but it is not. For instance it does not describe gravity, space, or time.

ZapperZ

But it still can! I mean, since we are SPECULATING, I can play that game too.

BTW, the fact that QM STOP at describing something that we have no ability to measure or detect is NOT speculation. It only says what it can, and NOT go beyond that. This is NOT speculation. It is simply knowing when not to act foolish.

You are still avoiding the issue. The fact that, unlike throwing a coin where even classical physics indicated that this is a deterministic event, a measurement of state out of a superposition has no such thing! This is the whole issue here! So if one wants to answer the original question of this thread based on what is accepted and verified and NOT based on speculation, there is only one way to answer this.

I am NOT saying QM is the end of all theories. Let's be clear on that. As an experimentalist, I love nothing better than to prove a theory wrong. However, what I "suspect" or "believe" or "want to happen" is NOT the same as what we know of and accepted today. I can make such distinction and would not want to answer this thread based on MY preferences. That was what I was pointing out to your original reply. You have not separated what you "believe" or think should happen with what is known and accepted.

Furthermore, let's not get into this "theory of everything" fallacy. I have written enough about this that it would be funny if you think that I would push for such a thing.

Zz.

Mazuz

My answer is no. It was good discussing this with you however, you definitely know your QM.

ZapperZ

I'm not actually surprised that you would answer it this way. In many aspects of human life, it appears that one can just simply make a statements without justification, or without explaining the mechanism leading all the way to a particular answer (example: gay marriages will undermine traditional union between a man and a woman. Just stating that appears to be enough without bothering to explain HOW such a thing will "undermine" such an institution).

Secondly, isn't it rather a criteria when one questions something to actually know about that "thing" as intimately as possible? I hate to think that I'm yapping about something out of ignorance of that thing - it would make the whole conversation as valid as talking about the weather. Does this not apply to you?

Zz.

Mazuz

You suggest that my answer to the question of whether or not there is "solid evidence for true randomness" in the universe is unsupported. I gave my reasoning but you don't want to go into QM not being a TOE, I respect your wish. But this idea is critical to my viewpoint on the question, only a theory of everything should be able to say whether the universe is inherently random. A theory of that describes less than everything can only speak relative to itself, not of the entire universe. You speculate that QM can somehow explain gravity, but that is only speculation therefore the answer to the question is still no.

BTW, just for confirmation is your answer to the question "yes" ?

ZapperZ

Correct, the answer is "yes", based on EXISTING physics.

Re TOE: There are many physicists, especially condensed matter physics, who do not think that there is such a thing as TOE. You may read one of my Journal entry on here if you wish. Secondly, you are making the explicit assumption that our universe MUST be deterministic and not "random". I, on the other hand, will take all commers. I have no psychological or philosophical reason to expect it one way or the other. I find it amusing that whenever a test is put to QM regarding the possible existence of "hidden variables" and other things that might hint that QM is incomplete, these tests continue to produce results consistent with QM in a spectacular fashion.

What it boils down to is this:

|psi> = a1|u1> + a2|u2>

If you can't tell me how, when, and which either state function is selected upon measurement, this conversation is over.

Zz.

Mazuz

Based IN existing physics the answer is yes, but existing physics is incomplete or more accurately, for describing the universe as a whole, wrong. There may or may not be a theory of everything (I wont even touch that) but if we don't have one, whether it is exists or not, we can't claim to understand something this fundamental about the universe. Without a full description of physics some questions will have to remain unanswered.

And no I have no idea how to interpret that math, and while it’s probably great to know and has its uses, I'm sure it has nothing to do with my line of reasoning.

ZapperZ

This this is EXACTLY what I meant by you doing speculating. I am NOT speculating when I based it on existing physics. It is ALL that we know of that are VERIFIABLE! We are not debating on whether things are complete or not. We are debating that to say BEYOND what we know, we are then speculating. This is what my reply to your first posting was.

I would LOVE to be able to answer questions such as this based on what *I* speculate MIGHT happen. Considering that some of my off-the-cuff speculations from a few years ago actually did turn out to come true (as a foolish undergraduate I described to a friend that the "potential" in Sch. eqn. can easily be gravitiational potential and we should be able to detected quantized gravitational effect), I would love to go off on a tangent and spew out my personal preferences. Unfortunately, that would quickly cause this whole thread to be dumped into the Theory Development section. Your statement (it is a statement, after all, devoid of any physical justification) that there has to be some underlying definiteness that QM is not describing is pure speculation. We have found none, and we have seen none of its effects.

QM may or may not be "complete". But at least it knows when to shut up and not describe things that it has no ability to.

Come again? That is a standard QM notation for a superposition of two basis functions. Considering that this is a discussion in the PHYSICS section and not PHILOSOPHY, shouldn't there be at least some physics substance in such a discussion? Thus, I bought up the simplest example of a superpostion in QM and ask you to describe how one can tell which state will be measured upon measurement. If you can't, then your assertion that there is some definiteness to this situation is pure speculation.

Zz.

Mazuz

This is my point, if it doesn’t represent the way the universe works as a whole it can't answer a question directed at the universe as a whole. It isn't QM claiming that the universe is inherently random, its you. I bet there are many quantum physicists who disagree with your interpretation of QM being able to make such a fundamental claim.

ZapperZ

How many "quantum physicists" do you know of personally?

Secondly, I don't think you know how the universe works, and more importantly, in what way the universe works that CONTRADICTS QM. Gravity does NOT contradicts QM. This is utter fallacy. Look at the recent neutron drop experiment! And if the string theorists have their way, they intend to prove that it is General Relativity that is incomplete, and not QM/QFT.

Again, this is a physics question. Show me which basis state that I will get upon a single measurement in that superposition system. This is the only part that matters.

Zz.

Mazuz

None, do they all share your view that as it stands now QM can make this ultimate claim?
No I don't know how the universe works.
This isn't the job of my argument, we have all ready established that QM doesn't represent the entire universe so it can't answer a question directed at the entire universe. You have all ready agreed that new physics may someday contradict QM, so if QM has proved your claim this shouldn't be possible.

In my opinion this may come down to what degree you think QM is touching on the fundamental level of the universe. I only know of QM, you seem like you actually understand it. If anything your opinion is a lot more qualified than mine.

ZapperZ

Where did *I* say such a thing? I left open the possiblity that QM isn't the last word. I never make a claim one way or the other, which would be strange because I would be doing exactly what you were doing - speculating! Unlike you, I am fully aware when I am trasversing the area of what we know of and what we don't.

TILL then, there's nothing that we know of that indicates that there's anything beyond QM. I've said this several times, but somehow, it isn't getting through. If you want to go beyond this, then you are speculating. We should then do this in, let's say, the Philosophy section, not physics.

Not only that, I've done experimental measurements on it, see others doing measurements of it, and observe results that simply have no classical analogue! I was at Brookhaven when the Stony Brook group announced the supercurrent SQUIDs results. Only if one has fully understood the subtleties of QM would one be astounded by such a result. For all practical purposes, this IS the Schrodinger Cat, and a FAT one at that! If you only have a superficial knowledge of QM, you would read it, yawn, and move on. As of today, this is still the clearest indication of the existence of superposition of states. I do not take experimental verification like this very lightly.

Zz.

Chronos

Golly, I thought determinism had passed on to that big theoretical scrap heap in the sky about 2 centuries ago. Randomness dominates the macroscopic universe and it does not seem unreasonable to suspect that it's turtles all the way down. Shall we repeal Heisenberg? Is it just a lazy way out because it's too hard to do the math? Perhaps some things appear to be random because they really are random.

Mazuz

Again you say that I’m speculating. I always speculate, but not in this very simple argument.

Maybe, except that to say that there is no theory that unites the universe more comprehensively is also speculation. Regardless.. a partial description of the universe, without speculating, can’t speak for the universe as a whole.

This is true, however is relative to a theory which does not fully describe nature.

Nor do I. I do not dismiss the results, they are real. But to interpret what they mean is not the role of QM.

We are not going anywhere with this argument. I understand your position. You are very intelligent and far more knowledgeable than myself on these matters, I respect your opinion. To sum it up you think QM demonstrates evidence for a truly random universe without speculating, I do not.

I think we can agree on a different question. Is the universe truly random? We don’t know (nor do we know whether the universe is deterministic or not). If we elaborate on this I believe we will end up each repeating ourselves.

Mazuz

Hi Chronos, I truly respect your thoughts and wisdom, but I'm not sure you have been following this conversation.

Perhaps it has, I don’t claim otherwise nor is my argument for determinism.

No it does not seem unreasonable, nonetheless this is speculation.

Yes, perhaps.

Gonzolo

When all observations have suggested randomness at the atom level, and none have have been contradictory, it is enough to convince me of a claimed fact. Physics is based on observation, and it concludes randomness at the atom level without any contradiction yet. Until someone observes a contradiction, randomness has to stay, and such has been the state of physics for the last 75 years.

Everyone is invited of course to do an experiment demonstrating determinism at the atomic level. A speculation is a hyothesis, that's the first step of the scientific procedure. Everyone knows the rest since they were 10 years old, but 6 000 000 000 people have had 75 years to follow through and still nothing.