From its earliest days nearly a century ago, quantum mechanics has proven itself to be a tremendously accurate yet intellectually unsatisfying theory to many. Not the least of its problems is that it is a theory about the results of measurements. As John Bell once said in introducing the concept of `beables', it should be possible to say what is rather than merely what is observed.This paragraph describes how Physics forked into hard science and philosophical beable-babble.
I am a logical positivist. So I have a simple attitude when you start talking about things that cannot be observed, then you as might as well be talking about ghosts. If there is no scientific observational way of saying that you are right or wrong, then it is just opinion, or philosophy, or religion, or some other immaterial belief. It is like you telling me that you like paintings of water lillies. I will not usually even have an opinion as to whether you are right or wrong, because it is not clear that any such opinion makes any sense.
Bohr, Heisenberg, and other creators of quantum mechanics were positivists.
At some point positivism fell out of fashion, and hardly anyone advocates anymore. But this beable stuff has gone nowhere. No good physics has resulted from beable theory.
The paper tells this story:
When I was in graduate school in Scotland, I was told the following parable by my advisors. An economist, a mathematician, and a logician were on a train traveling north. Just after they passed the Scottish border they noticed a single cow standing in a field. The economist remarked, "That cow is brown. All cows in Scotland must be brown." The mathematician replied, "No, one cow in Scotland is brown." The logician quietly but firmly muttered "No, one side of one cow in Scotland is brown." There are many versions of this parable involving a variety of professions and there are any number of lessons to be taken from it. It is usually meant as a dig at one of the particular professions that is included, especially when told by a member of one of the other professions. At the heart of the parable, though, is an open question: how much can we reasonably infer from a given observation?The author thinks that the mathematician is the most reasonable of the three.
At least cow color can be measurement. Many of the arguments about foundational quantum mechanics involves things that cannot be measured.
But measurement supposes a way to measure. The religion of measurement doesn't make sense to me because it presupposes what is significant. If one doesn't believe in non-locality then what does non-reality mean? Positivists are advocating a kind of Kantian mysticism, given that a psi-epistemic view is basically a negative statement. I know the world is not a giant atlas but that's not a very helpful observation. It's not a pogo stick either. The world is not a lot of things. I don't think positivism is science but an extremist position of philosophers. What's lacking is a common sense definition of understanding. I don't think QM has reached a level where people feel they truly understand it. That doesn't warrant wild and untestable theories but it doesn't mean we are only stuck talking about the current generation of thermometers. I think scientists are walking too tall thinking they understand things.ReplyDelete
There is nothing negative about being happy with a theory about the results of measurements. That is the core of what science is about. QM is only intellectually unsatisfying to some because they want to philosophize about unmeasurable realities.ReplyDelete
I didn't mean negative in terms of attitude but explanation. I can make measurements of planets and have many competing theories about how they ultimately move. It's not a satisfying theory to end in mysticism. That's against every intention of science. I ask, if it isn't non-local, then what is non-real? Note, words are largely invented to circumvent thought.Delete
For instance, David Hestenes makes the following observations.
"Specifically, I claim that an analysis of Dirac theory supports the following propositions:
(P1) Complex numbers are inseparably related to spin in Dirac theory. Hence spin is essential to the interpretation of quantum mechanics even in Schroedinger theory.
(P2) Bilinear observables are geometric consequences of rotational kinematics, so they are as natural in classical mechanics as in quantum mechanics
(P3) Electron spin and phase are inseparable kinematic properties of electron motion (zitterbewegung).
...It strongly suggests that quantum phenomena have a substructure that is not fully captured in anybody’s theory."
"the most peculiar features of quantum mechanical wave functions have kinematical explanations, so the use of probability theory in quantum mechanics should not differ in any essential way from its use in classical mechanics."
I don't think the final word has been said about quantum mechanics, and again, measurements depend on what you are trying to measure. Different substructures require different approaches. Pauli didn't come up with spin from simply measuring things. Data is useless without framing.
If you have competing theories of planetary motion, and they are all consistent with the measurements, then I cannot say that one is more correct than the others.ReplyDelete
A positivist does not attempt to say what is non-real. That is left for philosophers and others.
I think that Pauli was trying to explain certain measurements when he came up with his concept of spin. But I don't have the history in front of me.
“It's not logic that is powerful. Logic is actually a weak method because it depends on fragile chains of inference.” — Alan KayDelete
Only an extremist thinks Ptolemaic epicycles are valid descriptions. That isn't science but pure philosophy. Only a philosopher would take such a dizzyingly abstract position. A positivist (philosopher) might not want to explain what is "non-real" but a scientist certainly wants a deeper answer. I guess what I’m saying is that positivism isn't synonymous with science. Popper wasn’t even correct about falsification because he refused to acknowledge the role of induction. It’s Popper’s view that leads to entertaining a bunch of wacky views until someone falsifies them.
It's like the C language. Many intelligent systems programmers will say that most high-level languages are poorly-designed, slow and use clumsy abstractions, for example C++. But they forget that C itself was a poor language because it supported so little abstraction. So we got hundreds of clunky and amateur languages trying supersede it. The minimalism of QM is the same.
I used the example of ad-hoc "spin" because there are experimentally testable theories that attempt to explain things at a deeper level. Nobody has exhausted the subject. We are just dealing with poor mathematicians chasing their "tails."
The blame for cranky physics goes to physicists themselves. Wet noodles!
Then I guess that I am an extremist.ReplyDelete
Popper was not a positivist. He wrote essays attacking positivism.
I don't think that Alan Kay understood logic.
That's a smug response. You haven't even learned the lesson taught by the flat earth society, an intentional joke on those who take it seriously. You can solipsistically have an explanation for just about anything, if you want to torture your theory enough. They have an answer for just about every objection people can raise. There is no causal nexus revealed by measurement but theories certainly give causal accounts of nature. Math relates variables in a directly causal way.Delete
I didn't say Popper was a positivist but most scientists claim him as their philosopher, even though they never read him. I think he got science completely backwards. Kay was saying that point of view is worth 80 IQ points. Deductive logic is not full-blown reason but what idiot computers do. You guys can't get a robot to walk across an uneven floor, so what does he care about "logic." Who's logic? What logic? Every pig can fly. Everything that can fly has propellers. Therefore, all pigs have propellers. Circular reasoning tells us very little.
Yes, many scientists accept Popper, but he was not a positivist and his philosophy is not my philosophy.ReplyDelete
I don't know what Kay was trying to say, but logic does not use fragile chains of inference. Just the opposite.
Yes, there are paradoxes that can be confusing.
My point was about philosophy in general, including positivism. It's a waste of time. A real scientist is looking for answers and not mysteries or meta-reasoning about them. A theory involves causal understanding and taking philosophical positions about the primacy of mere measurement (problematic in its own right, especially in QM) doesn't satisfy a real scientist trying to understand the world.Delete
Logic does use fragile chains of inference because it tries to decompose reasoning in a fine-grained and completely deterministic way. I have proof: you can't even get a robot to clean the house or walk across an uneven floor. Maybe you don't understand logic. Usually, we lump many assumptions together and work within a powerful context which bypasses explicit logical calculation. The brain does not deduce things with logic. Logic is only an emergent property of brains. Set theory is a great example of a largely unproductive endeavor simply restating what we already know. It's mere philosophy or "meta-math." Banach-Tarski shows that infinite math has no physical mapping.
All I'm saying is that QM does not provide a very deep explanation. It's going on a hundred years of science completely failing to go beyond it. If you are going to say something is simply "non-classical" then you have to explain what you mean. I can't use that type of reasoning in any other branch of science and get away with it.
Epicycles are not 'real', you can actually use them to great effect, but if you use them as a model, you will have no fracking clue how the actual solar system operates mechanically, and you will be cut off from further concepts such as gravity, orbits, galaxies, etc on upward through the macroscopic scale.ReplyDelete
Likewise, if you are putzing around with Rutherford atomic models, you may be able to do basic chemistry, but you will have no actual understanding of what the heck an atom actually is, or how they function together structurely. No, it isn't by the magic of wishful 'electron bonding', and no, atoms are not composed of lumps of nucleus monkey bread surrounded by clouds of probability electrons. Weak and strong forces are outright fudges covering for an incredible lack of actual structural understanding of the physical nature of charge and what role it plays in how atoms move and function the way they do.
You can use a faulty 'positivist' model and match actual measurements to it until you go crosseyed, all kinds of measurements were being matched to epicycles for many years...that was the problem. It just got so absurdly complicated covering for the faulty model by creating ever more increasingly ridiculous fudges to cover the model's failure. The exact same can be said for the 'big bang theory','Carbon Anthropogenic Global Warming' and 'superstrings', models which have become top heavy kludges propped up by ever more convoluted excuses- no matter the new data, they can be stretched into any shape to hide failure.
What the scientific community does not seem to be able to come to grips with, is that EVERY system can be gamed or hacked given enough understanding of how the manipulate that system. No system is foolproof or above manipulation or corruption, if humans are involved, it is fallible. If you are looking for purity of truth and thought, you will have to put far more conscious vigilance into policing those who would use such systems to their own advantage seeking power and influence in the name of vapid appeals to 'the greater good' or 'science'.
Kings were once considered above doubt by divine right.
Priests were also placed above the field of doubt by the pretense they were divorced from 'earthly matters' in their contemplation and supplication of the divine.
Strange thing was, kings and priests were nothing but masters of manipulating 'earthly matters', corruption and deceit was in no way foreign to their pursuit of power.
Nowadays, we pay homage to an esoteric priesthood of complication and authority which is now openly challenging the very underpinnings of freedom of thought, becoming practically unquestionable to mere mortals, and backed by the financial power of the state...what could possibly go wrong with this new state run religion. Go figure.
I agree. People create causal models to make predictions. Measurements only measure state. The transformation is largely what we care about. This basically requires intuition and guesses but certainly based on prior evidence and observation. When you make a measurement, you already frame and assume what you are measuring. Just for fun, let's say there are less than systematic phenomena in the universe, such as my above use of hyphenation and "who's" carelessly. I notice some days that I do this like crazy and other days I don't make mistakes at all. Many days I type a lot of homonyms without realizing it or my typing becomes very scrambled. Not everything is regular.Delete
I guess the cow was just too far away for them to consider the effect of Brownian motion.ReplyDelete