Tuesday, April 6, 2021

Philosophers try to discredit Realism

John Horgan writes in SciAm:
Although my realism has been wobbling lately, I remain a realist. ...

Filmmaker Errol Morris, who studied under Kuhn in the 1970s and ended up loathing him, contends that Kuhnian-style postmodernism makes it easier for politicians and other powerful figures to lie. Philosopher Timothy Williamson makes a similar point in “In defence of realism.” “Imagine a future,” Williamson writes, “where a dictator or would-be dictator, accused of spreading falsehoods, can reply: ‘You are relying on obsolescent realist ideas of truth and falsity; realism has been discredited in philosophy.’”

I agree with methat, but I am afraid it is a losing battle.

Not only are philosohers denying realism, so are physicists, increasingly. And even those who agree with me on interpretations of quantum mechanics have conceded the term realism. That is, they will say that Copenhagen is not a realist interpretation, because we cannot simultaneously say the electron's position and momentum are.

4 comments:

  1. Roger,

    >> "I agree with me..."

    What's that? a typo?

    Best,
    --Ajit

    ReplyDelete
  2. Roger,
    the losing battle is bigger than most imagine. I believe our civilization has been poisoned.

    Postmodernism has only been able to tear things apart under the pseudo intellectual pretense of analysis, and has never been able to put things back together, much less create or innovate through synthesis.

    Postmodernism is badly disguised nihilism with a purpose. Its intended function is to divide people, undermine the credibility of vital institutions, and destroy beauty and rational thought in western civilization.

    ReplyDelete
  3. Roger,

    Re. The very last sentence of your main text.

    The Wiki on the CI (https://en.wikipedia.org/wiki/Copenhagen_interpretation) says, right in the third paragraph from the top:

    >> "Hans Primas describes nine theses [...snip...] complementary properties cannot be observed simultaneously; no truth can be attributed to an object except according to the results of its measurement;..." <<

    Then, in the section "Principles", it again says that:

    >> "Hans Primas and Roland Omn├Ęs give a more detailed breakdown [...snip...]
    5. Statements about measurements that are not actually made do not have meaning." <<

    ---

    The situation is like this.

    The position and momentum of an electron are complementary; see https://en.wikipedia.org/wiki/Complementarity_(physics) . That is to say, x and p cannot be measured simultaneously.

    This much is what CI says, and the mainstream QM (MSQM) also seems to agree.

    Then, according to CI, no truth can be attributed to p if x is being measured (or to x if p is being measured). Indeed, according to the CI, p has no meaning if x is being measured (and x has no meaning if p is being measured).

    That's what the *CI* says. In contrast, the MSQM has no positions on issues like meaning and existence; it deals with the calculation procedures, and then stops right there.

    Now, where does that leave us?

    Consider this question. In general, when is it that we say that something has no meaning? Here, by "something", I mean not a concrete thing as such, but some word, some *concept*, ... in general, some *mental* abstraction / idea. So, the question is: When does an idea have no meaning whatsoever?

    Answer: When it doesn't refer to something specific in reality, or when it cannot refer to anything in reality. As an example: A man who grows green vegetables on the top of his head, and eats them as his staple food. This "idea" is meaningless. That's what something being "meaningless" actually means.

    If something (some idea) *is* meaningless in a context, it doesn't have valid referent in reality (at least in that context). In other words, it doesn't exist. You can't say "it is". Not in that context.

    So, it is the CI itself which directly implies that when x is being measured, p does not exist; the reason being, it is not meaningful to talk of p in this context because p too cannot be measured in the same experiment, x and p being complementary.

    That's my understanding of the CI. (Note, MSQM simply states the maths and stops right there.)

    Now, I gather from your last sentence that you want to say that even according to CI, both x and p are in existence at all times (whether either is being measured or not).

    OK. This may be a good position to keep (at least in IMO). But please note, the CI itself doesn't permit it.

    So, you either have to give up the CI or the aforementioned position.

    (I would like to know if there exist any other choice(s). I think not. I think it's a straight-forward matter. Either the CI, or both x and p existing at all times for an electron. No third choice.)

    Best,
    --Ajit

    ReplyDelete
  4. Yes, CI does not allow measuring position and momentum at the same time.

    ReplyDelete