Thursday, June 26, 2014

Carroll defends lousy philosophy

Physicist Sean M. Carroll is trying to defend philosophy in the current Physics-Philosophy wars:
“Philosophy is completely useless to the everyday job of a working physicist.”

Nobody denies that the vast majority of physics gets by perfectly well without any input from philosophy at all.
Pretty weak. He has no reply to this comment:
Could you elaborate a bit more and name one or more examples where “philosophical input is useful” to science, or better yet, physics?
Lumo trashes him:
In particular, the phrase "shut up and calculate" has been used in the context of the foundations of quantum mechanics. Virtually all the philosophers misunderstand the quantum revolution – the very fact that the quantum revolution has forced us to describe Nature in a way that is fundamentally incompatible with the most general assumptions of classical physics and "common sense". They talk a lot and almost everything they say about these problems is pure junk.

Quantum mechanics brought us a new framework for physics and science and it is rather simple to summarize it. Only the results of observations – perceptions by observers – are facts that may be talked about; and the laws of Nature can only calculate probabilities of the individual outcomes from squared absolute values of the probability amplitudes – using the mathematical formulae that apply in every single context of the real world and that are easy to summarize.

The previous sentence summarizes everything that is scientifically meaningful according to the new (well, 90 years old) framework of physics. Every question about Nature that doesn't respect this general template is scientifically meaningless. Every claim about Nature's inner workings that disagrees with the general postulates of quantum mechanics – postulates that render most classical assumptions about the world incorrect and most classical questions about "reality" meaningless – is wrong. ...

What is particularly ironic – and hypocritical – about Carroll's attitude is that he is one of the loudest critics of religions and everything associated with them. Nevertheless, he frantically defends "philosophy" as a way to learn about Nature. It's insane because philosophy is exactly as unscientific as religion. Every religion may be called just another philosophy and pretty much all philosophies and religions are equally deficient when it comes to their basic flaw – the violation of the rules of the scientific method.
I agree with Lumo. If the philosophy of science were so valuable, then the proponents would be able to give some examples. But the philosopher defenders are almost entirely people who deny the scientific method, deny the progress of science, deny that science discovers truths, deny the Copenhagen interpretation of quantum mechanics, and promote silly ideas without evidence.

The philosophers have been at war with science for 60+ years. I am glad to see some physicists point out how worthless their criticisms are.

Here is a new article on the philosophy of quantum mechanics: Circumveiloped by Obscuritads:
Maybe calling a Hilbert-vector (or Weyl-ray, or ...) the mathematical representative of the physical state of a physical system is a mistake: a Hilbert-vector should remain a physically uninterpreted and purely mathematical concept in QM, an auxiliary device to calculate probability distributions of measurement outcomes. There is no ‘physical state’ of the unmeasured cat in purgatory: we are led to believe that the cat has, or is in, a physical state by mistakenly trying to attribute physical meaning to a Hilbertvector that is a superposition of two vectors, which according to the standard property postulate we associate with a cat having the property of being dead and one having the property of being alive, respectively. We believe the unmeasured cat is some particular physical state but perhaps it isn’t. QM associates a Hilbert-vector to the cat, which is devoid of physical meaning, but enables the computation of probability measures over measurement-outcomes, which are full of physical meaning. Thus we have physical meaningfulness out of physical meaninglessness. Sheer magic. Magic does however not help us to understand physical reality.

The wilful jump to meaninglessness seems however a cheap way out. I don’t like it. We believe that the unmeasured cat is either stone dead or breathing, because tertium non possibilium, and we want QM to be logically compatible with this belief, at the very least, and preferrably to imply one or the other belief. After all, QM also predicts that as soon as we peek at (i.e. measure) the cat, through a pinhole, unbeknownst to the cat, it is either dead or alive. Rather than to withhold physical significance from the Hilbert-vector, we should try to assign physical significance to it (or to a Weyl-ray, or ...). For how else could it determine physically meaningful probability measures over measurement-outcomes?
I don't know if this article is serious or not. He seems to understand quantum mechanics, and makes some valid points, but he also seems to be mocking the whole subject.

Here is another:
Philosophical roots of the "eternal" questions in the XX-century theoretical physics

... If we compare XX century physics to a building, we have to say that not only its two bases are not linked into a single foundation, but each of them is full of contradictions (paradoxes). The number of “thunderstorm clouds” in the physical theory is ten times more today than in 1900. After decades of search and debates, even the direction of further research is not defined. Moreover, unlike the XVII-XIX century physics, it has no clear boundaries between the known and the unknown, the reliable and doubtful, true and false. ...

A. Einstein wrote in 1938: “...Nowadays, the subjective and positivist view prevails. Proponents of this view claim that the consideration of nature as an objective reality is an outdated prejudice. That's what theorists involved in Quantum mechanics put to their merit” [20]. ...

As long as the idea of denying objective reality, borrowed from the positivist philosophy, lies in the foundations of Theory of relativity and Quantum mechanics, it is impossible to overcome the crisis of physics by some partial improvements in these theories. This is convincingly demonstrated by the history of physics of the twentieth century. It will only be possible to find a way out of the crisis if the physical theory is based on the principles of classical physics.
This is wacky stuff. He thinks that 20th (XX) century physics is in crisis because of some philosophical disagreement with positivism.

1 comment:

  1. Chemists turned philosophers often take issue with quantum mechanics inability to explain molecular structure, periodic table of elements, etc. Jan C.A. Boeyens book "The Chemistry of Matter Waves" Springer c2013 is 250 pages of quantum mechanics trashing on every second page eg.

    ".With each further step into the unknown quantum models based on the Copenhagen
    orthodoxy create more problems than they solve. In the case of chemistry,
    where this theory dictates a point description for molecules with demonstrable nonzero
    extension, the situation borders on the absurd. Reluctance to challenge authority
    has created a computational edifice, completely divorced from reality, but
    dutifully supported by educational institutions around the world. The sad fact is that
    quantum chemistry further dilutes the dictates of elementary wave mechanics to the
    extent where it operates at the classical level, using unnecessarily complicated algorithms
    with a vague resemblance to quantum formalism. Mindless extension of
    such practice to the life and behavioural sciences results in the grotesque philosophies
    widely claimed to be quantum based. Although quantum effects are real the
    supporting theories have gone haywire. Blind belief with ecstatic fervour is not the
    way forward. The time has come to critically re-examine the hasty conclusions of
    the pioneers and, not only for an alternative explanation, but for a more appropriate
    formulation of non-classical theory."