Lobstrosity

Evidence has since shown that Einstein was wrong--his view of quantum mechanics was faulty. He maintained that there was such a thing as local realism, that there were hidden variables we simply couldn't measure and that the probabilistic nature of quantum mechanics was a mere mathematical tool rather than the true picture of the world. This is incorrect.

No, the existence of POs would produce testable differences that would deviate from the predictions of quantum mechanics. POs are fundamentally at odds with quantum mechanics and as such either quantum is wrong (not very likely given all of its experimental validation) or it's pointless to think about POs because they have no bearing on reality. Why can't a PO exist? Well a PO would simutaneously know a particle's exact position and exact momentum. The problem is that a particle doesn't actually have an exact position and an exact momentum simultaneously. This has nothing to do with our technological inability to make measurements. It's a fundamental property of the particle. A particle is nothing more than a wave function, literally. It does not possess both quantities at once, so how could a PO possibly claim to know both quantities at once?

Bob K

QM probabilistic theory is based upon the observation that humans cannot observe and not disturb small stuffs, therefore the causality/determinism of small stuffs cannot be observed and therefore perfect predictability of small stuffs cannot be achieved; the average number of changes of small stuffs in crowds of small stuffs can be observed and therefore blended into probabilistic formulas, hence the development of the specific QM mathematics. QM mathematics thus remains the current effective description of the matter/energy present in the universe. Eliminate the observational problems so individual small stuffs can be observed directly, and the causality/determinism/predictability of individual small stuffs will appear along with the precise numbers of individual small stuffs which will change in crowds of small stuffs, and those numbers ought to agree reasonably with the probability predictions of QM mathematics. Thus, in regards to "[Einstein's maintaining] that the probabilistic nature of quantum mechanics was a mere mathematical tool rather than the true picture of the world", he was correct. The problem has always remained the reality of the fact that with the then present and now current scientific thinking and realities we cannot observe and not disturb small stuffs. The PO theory shows what would happen if the observational problems were eliminated by observers with no limitations who could observe and not disturb directly individual small stuffs.

I use the humorous term 'stuff(s)' as in 'small stuffs' to refer to whatever is a 'particle,' whether it be a 'wavicle' or otherwise discernible as either a particle or as a wave. I continue to maintain that because a small stuff has impact because of the observed 'quanta' of energy needed to cause emissions of stuffs from metallic strips impacted by other stuffs that the net effect of small stuffs is not a wave function but instead is that of a particle, a thing which has impact capability and therefore the equivalence of mass causing a force as a push or a pull, and in the case of an impact, causing a force which is a push.

Bob K

What is your supporting evidence for your claim that "[The] existence of POs would produce testable differences that would deviate from the predictions of quantum mechanics"? Is it not entirely possible that PO observations/predictions might coincide with QM predictions? After all, if QM is effective it must be reasonably accurate, and if it is reasonably accurate, then it ought to predict the future of a number of small stuffs close to the number of small stuffs for whom their future would be predicted by POs.

One of the reasons QM got started was the fact that A. Einstein showed that particles whacking a metal strip caused emissions of other particles in 'quantas', specific quantities. A specific quanta of energy was needed to cause the emission of a particle. Thus, a particle does in fact act as if it has both velocity and momentum regardless of the theory of the wave function wherein a particle is everywhere and anywhere until it hits something whereupon it suddenly develops the mass or the functional equivalent of mass needed to register an impact or cause a track in a cloud chamber.

The PO theory, which has no observational limitations, shows that the velocity/momentum would be observable and observed by POs and, therefore, the causality/determinism among small stuffs would be established and perfect predictability for small stuffs would likewise be established.

Thus, the PO theory lives.

Lobstrosity

I said it before, but I'll say it again: according to experimental evidence there are testable differences between local realism (i.e. the theory of the perfect observer) and quantum mechanics. It is not merely a mathematical convenience to use probabilistic calculations. From A Modern Approach to Quantum Mechanics by John Townsend:

"Until 1964 it was believed that one could always construct a hidden-variable theory that would give all the same results as quantum mechanics. In that year, however, John S. Bell pointed out that alternative theories based on Einstein's locality principle actually yield a testable inequality that differs from the predictions of quantum mechanics."

Your understanding of quantum mechanics is somewhat antiquated and does not actually mesh with reality. Experimental testing of the Bell inequalities has shown local realism to be faulty. In one of the most precise experiments, the Bell inequality was violated by more than nine standard deviations while the agreement with quantum mechanical predictions was excellent. Einstein was incorrect. If you want refererences, check out:

A. Aspect, P. Granger, and G. Roger, Phys. Rev. Lett. 49, 91 (1982).

Or look up the Bell inequality in any modern Quantum text.

The theory of the perfect observer is dead, though a few researchers today still strive to revive it's lifeless corpse (probably because they cannot handle the true bizarre nature of quantum mechanics).

One final quote from Townsend on this:

"So where does this all leave us? Certainly with a sense of wonder about the way the physical world operates. It is hard to guess how Einstein would have responded to the recent experimental results. As we have noted, he believed that all particles should have definite attributes, or properties, independent of whether or not these properties were actually measured. As A. Pais recounts: 'We often discussed his notions on objective reality. I recall that during one walk, Einstein suddenly stopped, turned to me and asked whether I really believed that the moon only exists when I look at it.' In the microscopic world, the answer appears to be yes."

ChuckieR

Hi O,

I think it's a very fundamental question that you ask. I'm not a physicist, so I can't go into Quantum technicalities.

Your "exactly" is exactly the problem. Acording to QM, you cannot make exact measurements, only approximations. So any "effects" will also be approximate. From coin flipping down to subatomic interactions, there are always uncertainties in the "initial conditions", so there will always be uncertainties in the outcomes. And you can't have it both ways. You can't complain that "I'm talking about a classical system; explain the randomness in a classical system", because a classical system is only an abstract approximation of reality (as QM is too, but at a lower level, and QM acknowledges the uncertainty).

The "exact" measurements of the classical system would not lead to probabilistic outcomes, which is why they had to come up with QM to explain how the world really works. So I think that answers your question as how classical systems generate probabilistic outcomes: they don't!

If you do a digital computer simulation of reality, and you do not intentionally introduce any randomness, then you will get exactly the same outputs for given inputs every single time (barring a random computer error!). But this is not how the real world works. You cannot have exactly the same initial conditions every time.

Try to come up with a real-world physical example, and you'll see that the smaller the "ruler" you use to try to measure the system, the larger the percentage of measurement error.

For instance if one of the objects in the system is a billiard ball that is sitting still, as you try to measure the exact initial position of this ball you will see that on a subatomic scale it is not sitting still at all - all of the subatomic particles are vibrating around. Your initial measurement can never be "exact".

This difference is called randomness or uncertainty. There is no way to perform exactly the same experiment twice. That is why we need to do statistics on multiple trials.

I suppose in some sense (as you may have been implying in your original post), there is no "cause" and "effect", there are only "interactions" of all of the wave functions. If your "cause" is a moving particle that strikes another particle, well something "caused" that first particle to start moving, and something caused that cause, etc. If you want to drive yourself really crazy you can take these causes all the way back to the big bang, which many believe was an uncaused event. So there.

Chuck