f wrote:
As physicists have left the classical world of Newton for the quantum world of Einstein & Associates, they have grappled with this *relative* problem of subjective/objective and have found that very, very, very little *out-there* is truly objective -- even those hallowed equations bend, fold, spindle and mutilate when quantum theory gets thrown their way.
I can't let this pass without comment.
Einstein, altho' he laid a big part of the groundwork for Quantum Mechanics, was from it's birth until his death a firm and vocal opponent of QM, and in particular the "standard" or "Copenhagen" interpretation, precisely because he could see that QM denies the objectivity of physical concepts. As the greatest (and last) CLASSICAL physicist, he could not accept that [Gg]od not only throws dice, but often does so where we can't see them. To paraphrase Hawking:
He demanded that an objective reality exist, and therefore insisted that QM was either incomplete, or was only an approximation to some deeper, classical theory to follow.
Note that both Special and General Relativity are strictly classical theories: in both all quantities are considered continuous (black holes not withstanding), any uncertainty is due to lack of knowledge. These days this position is held by another great mathematical physicist: Roger Penrose. Penrose wants that objectivity back for the same reasons that Einstein wouldn't let it go -- physics is a lot more mathematically neat, and *much* more comfortable to live with if it is objective. Penrose has yet to come up with any experiment (let alone any experimental evidence) that would lead us to the return of such objectivity.
Relativity did greatly change our understanding of the universe however. The main shocker is that it does away with the notion of simultaneous events. Observers in (greatly) distant locations are simply unable to arrive at a shared description of the passage of time.
I don't know what Penrose's treatment of the EPR/Bell/Aspect result is: he tends to gloss over it in his books. Einstein thought the EPR result was a death-blow to QM, Aspect's confirmation of Bell's reduction is instead the death blow to classical objectivity: there are NO objective facts to be found. Note that a new deeper theory won't help you here, Aspect's experimental results would still be true, and would still demand the non-objectivity of physics.
This is a direct confirmation of the core idea in QM: uncertainty now may have two sources--
- the classical lack of information --- called a mixture
- AND the quantum wave-function collapse --- called a superposition.
What I'm leading up to here is that QM, while it denies objectivity in the sense that classical physics relied on, is in no way less rational, no less well-defined, no less stringent in its formalism (more so, actually) than classical physics. And you have no choice.
Aspect's experiment is repeatable. Physical measurements are not objective ... provided they are carried out on entangled quantum systems. There is nothing ... er, how to put it ... there's no sense in which quantum physics is any less any of the things that people who don't like classical physics don't like about classical physics, than is classical physics. If you see what I mean.
Non-Einsteinian Classical physics (the physics of Gallileo, Kepler, Newton, Kelvin etc.) is common sense physics: its ideas arise from every day events as directly experienced by humans. It turns out that with this (very) narrow domain it simply does not apply (and why should it?) For me, the most important lesson of modern physics is that *demonstrably correct* descriptions of the universe do not have to make sense. The (correct) predictions of Relativity and QM are, where they differ from Newton et. al., *all* counter-intuitive.
I find this a very interesting thing: obviously the sun goes round the earth, but it doesn't; it makes sense that gold is the sweat of the sun, but it isn't, every one knows that diseases are caused by bad smells and demons, but they're not, it's obvious that the brain exists merely to cool the blood, but that's not so, and so on. I see the whole of human history as a slow climb out of self delusion based on the makes sense model. Some would like us to return to it. Well, that's fine, but before you go: please hand in your childhood inoculations and all dental work, and all the time you spend not gathering food and fuel to survive.
The two big challenges in contemporary physics, (one of which f mentioned earlier) are to merge QM and General Relativity, and to explain how the quantum world comes to look just like the Newtonian one within the domain of validity of the latter. It's by rolling both of these together that Penrose wants to get the objectivity back. These are hard problems, both technically (doing the maths) and philosophically, but they do not cause hard-nosed, left-brain science to blow up in the way the quote at the top seems to suggest.
Remember the caveat on the Aspect result: entanglement.
Preparing entangled systems is very hard, you don't get them outside the lab. In my view the harder of the two problems above is the second:
Why does the quantum universe seem classical when observed with un-aided human senses?
So to the punchline (well done if you've bothered to stick with me so far, and thanks): QM says the universe does not admit of objective physical quantities, but, the world of direct human experience seems to--no one yet knows how one turns into the other, and it is, in my opinion, a mistake (almost a category mistake) to try to use the quantum result to make strong statements about the directly experienced world (until that relationship is known).
Since, you or I (or anyone for that matter) is stuck within him/herself I suggest the following modes of thought that each can access individually ...
Alternatively, get out of yourself with the simple and effective Scientific Method.
Repeatability
Repeatability
Repeatability
