Re: Feynman Quotes For Don G. (and others interested of course)
- From: Alpha <omegazero2003@xxxxxxxxx>
- Date: Tue, 28 Oct 2008 08:01:16 -0700 (PDT)
On Oct 26, 9:30 am, Don Geddis <d...@xxxxxxxxxx> wrote:
Alpha <omegazero2...@xxxxxxxxx> wrote on Sat, 25 Oct 2008:
I posted a quote or two from Feynman in the past and knew he had said them,
but could not remember where. I was glancing over some physics books in my
library the last couple of days and came upon the following:
"I think I can safely say that nobody understands quantum mechanics."
(Richard Feynman, The Character of Physical Law, p. 129, MIT Press,
Cambridge, MA, 1965).
1965 was a long time ago. Feynman was a (very!) smart guy, but science
moves on. I know more about physics, today, as a layman, than Newton did
in his day (even though I'm obviously no Newton).
Everett only invented multiple worlds in 1957, and it took many years for the
community to appreciate the significance of the insight.
I wonder if we can find any Feynman quotes on QM philosophy and
interpretations from the end of his life. Feynman was certainly smart.
I suspect he wouldn't have repeated that quote in the late '80s.
Also: I have much more respect for the physicists (like Feynman) who, in the
early days of QM, used an interpretation of "just shut up and calculate",
rather than committing to the obviously confused Copenhagen interpretation.
Feynman's statement -- while not as good as we can make today -- is far
better than those who professed a false interpretation.
Also of interest is an alternative statement from Feynman (also as
given by physicist P. Wallace in: Images of the Quantum (a book I
referred you to, Don, a while back as an "interpretation-free" look at
the QM/QFT world))
I'm kind of embarrassed to admit this, but I'm actually trying to follow your
advice. I found a cheap (used) copy of the book, and I'm halfway through:
http://www.amazon.com/Paradox-Lost-Philip-R-Wallace/dp/0387946594/ref...
Not bad at all. So far, in the first half, I've found nothing to object to.
I actually wonder why you recommended it to me. It seems to match the kinds
of things I've been posting on this group over the last year -- but I thought
you were always arguing on the other side of those posts. Well, I hadn't
intended to comment until I finished the whole thing. Perhaps there's some
big revelation at the end that I'll disagree with. But so far, it doesn't
seem like it. So far, he makes fun of the same philosophical errors on the
part of his fellow physicists that I was making fun of.
The book came out in the mid-90's. I actually prefer this more recent
explanation:
http://www.overcomingbias.com/2008/06/the-quantum-phy.html
in particular this sequence:
http://www.overcomingbias.com/2008/06/mwi-wins.html
But really, they seem to say much the same kind of thing. (I just got to the
chapter in your book, where he laments the label of the "Heisenberg
Uncertainty Principle". Not the mathematical theory, which is of course
correct like all the rest of QM. But the name "uncertainty", which
encourages people to misunderstand the theory, as though it were something
about our state of knowledge and what we, as humans, are able to learn about
the world. Like, "you can't measure something without disturbing it".
That's not what the math is about at all, even though that was a popular
quote often used -- incorrectly! -- to "explain" HUP.)
as follows:
Says Feynman: "I am going to tell you what nature behaves like." If,
Feynman says, one asks the question: "But how can it be like that?",
the answer is: "Nobody knows how it can be like that."
That's either a deeper question, or else from an earlier time in science.
At the beginning of QM, there was no good understanding for "why". But that
has changed a bit since Everett.
But, a bit deeper, you can try asking a "why" question of any scientific
theory. Gravity on the earth's surface is about 9.8m/s^2. "Why" that number?
Why not 2m/s^2? Why not 100m/s^2? Why the 9.8 number?
It's hard to imagine what an answer to that question would look like, even in
theory.
Science is about "what" happens in the universe. It's about predictive
theories for future experiments and observations. The point behind a "why"
question is often more about how human brains think, and what kinds of
stories "feel satisfying", than it is a question about how the universe
works.
Why is the speed of light constant? Why is there a universe at all, rather
than not? Etc. Why why why.
Wallace's book, is as I said, a look at physics/QM/QFT "as is", with
notes about how paradoxes arise when such is interpreted in various
ways. It is a good historical accounting of the development of the
different points of view/interpretations that paralled the theoretical
and empirical work since the early 1900s too.
Yup. It's vastly better (in the first half, so far), than the large bulk of
popular accounts of quantum mechanics that I've heard of in the past.
My main question then, is why _you_ like the book. As far as I can tell,
it doesn't support anything you've been saying on this newsgroup about QM
for the last year...
(Well, ok, I'll at least give you this: my recommended sequence is a defense
of Multiple Worlds, and Wallace's book so far [first 1/2] has only mentioned
MW in passing. It's mostly just tearing apart the alternative presentations.
But as I thought I understood you, you're a fan of "consciousness is special"
and "quantum wavefunction collapse due to observation" and maybe Penrose's
"quantum consciousness" and all that stuff. Wallace's book certainly doesn't
support any of that.)
Sorry about the duplicate post (Google seemed not to initialyy post
anything for a long time so I reposted later) ; I answered your other
reply in that thread.
AFA what I believe, I like (as I said in the other post) to come to
grips with what various POVs have to say on the matter, without
actually coming to any final conclusions on the matters myself, as I
think there is much more unknown than known about many of these
matters.
It is more a matter of *not dismissing* other POV/interpretations or
applications of QM, because as Feynman said, nobody (and I believe
that is as true to day as it was then) understands QM; I would add to
that sentence the following: "...to the extent necessary to come up
with a fully consistent, statisfactory interpretation as to what is
really happening."
AFA Wallace's tearing apart aspects of interpretations, he does do
that but notice that he sometimes comes up with sentences that
actually *are* interpretations himself; subtle and you have to know
what to look for, but they are there. As I state in the other post,
the rendering of the math into sentences begs interpretations as words
are wont to do. Wallace has his own interpretation of those sentences
and they come with assumptions as well.
BTW, as you get into more of the book you will see he uses
"uncertainty" and "indeterminism" as bona fide actualities of QM. Such
may not be a function of person's observations/measurements, but they
are sure qualities of QM proper; and that is strange!
I'll take a look at the refs you posted - thanks!
.
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