Re: Original Sin

Dianelos Georgoudis wrote:

These are not good analogies, because it's a fact that many of those
who thought about the implications of quantum mechanics for objective
reality felt that consciousness plays a fundamental role.

In the early days of QM, yes. Now that physicists have had
longer to think about it, I think that's very much a minority
view.

I don't think there was ever a time where most physicists worried
about the ontological implications of quantum mechanics one way or the
other. You may be right that most of them are not even aware there is
a serious ontological problem implied by quantum mechanics. In any
case the evidence that many physicists do not speak of this problem is
much weaker than the evidence that some physicists do speak of it,
even today.

That's fair enough, since I never denied that some physicists
do speak of it.

that quantum mechanics appears to imply that physical reality is *not*
observer independent, which is a polite way of saying that physical
reality is not objective.

I don't think quantum mechanics implies any such thing.

Doesn't it bother you that extremely knowledgeable physicists even
today think it does?

The fact that some extremely knowledgeable physicists think
it does is evidence that it does. The fact that some extremely
knowledgeable physicists think it doesn't is evidence that it
doesn't. I'm not sure why I should be *bothered* by any of
this. (If there were any reason to believe that the great
majority of people who've thought hard about this stuff
disagree with me, *that* would be reason to be bothered.
If there is such reason, I haven't seen it.)

In this context, how do you explain Wheeler's
delayed choice experiment? (The most concise explanation of that
experiment I know is to be found on the diagram on page 165 of Nick
Herberts "Quantum Reality", which you can read here by clicking on
that page here:
http://www.amazon.com/gp/reader/0385235690/ref=sib_dp_srch_pop?v=search-inside&keywords=delayed+choice
).

I don't see that there's any problem. Sorry if I'm being dim.
The caption talks about "a photon" taking one path or two
paths around a distant galaxy, but obviously that's nonsense;
photons taking paths are merely a (very) convenient approximation;
do the actual calculations and you get the results shown in
that diagram; what's the difficulty, exactly?

(I think that if you take the experiment as shown there at
face value -- an actual galaxy, an actual quasar, etc. --
then you won't see anything like the results described
because of decoherence, but I may be being dim.)

1) Only a few of physicists worry about the ontological implications
of quantum mechanics, but these who do worry, including some of the
greatest physicists of the 20th century, found quantum mechanics
deeply paradoxical [1],

Granted, but I'll also note that great physicists who
have thought about this stuff more recently seem to be
more of the opinion that QM is weird and counterintuitive
(which it certainly is) than that it's *paradoxical*.

Can you back this up?

I haven't seen anything like a survey of Great Physicists
on this point, if that's what you mean. But I'll cite
Gell-Mann and Feynman as examples of unquestionably
great physicists of recent years for whom QM is weird
rather than paradoxical, and who have (had, alas, in
Feynman's case) no truck with the idea of making
consciousness, or conscious observation, a fundamental
notion in physics.

I just did a quick trawl through my physics books. I don't
have many books by great physicists that say much about QM,
or ones that make the positions of great physicists clear,
but it looks like

- Gell-Mann, Feynman and Hawking are for "weird" rather
than "paradoxical" and don't see a fundamental role
for consciousness

- Penrose likes to call things paradoxes, and does see
connections between fundamental physics and consciousness,
but not your sort -- rather, he thinks that human thought
exploits quantum effects

- Dyson is somewhere in the vicinity of your "consciousness
creates reality" position

In so far as my bookshelves give a fair sampling of great
physicists of recent years (i.e., not very far) I think
this supports my contention that "weird" is closer to being
the consensus view than "paradoxical" among recent great
physicists who've thought about these issues. (I would say
that Gell-Mann and Feynman are clearly the best of the
physicists in that short list.)

3) These paradoxes are contingent on the ontological position of
scientific naturalism [2],

No, sorry, not buying that. You say the paradoxes go away
when you adopt theistic idealism; I think this is just one
of many instances in which you find your view better by
applying lower standards to it.

I am not sure what you mean by that. I think it's a fact that if one
considers that we live within a computer simulation (instead of, as
how scientific realism has it, in the physical universe as described
by science's models) then the quantum paradoxes disappear. Why?
Because a computer's simulation would simply present us with just the
phenomena that quantum theory predicts - no possibility of a paradox
there. In exactly the same way idealistic theism avoids these
paradoxes; the only difference is that now it's God and not some
computer that produces our conscious experiences.

Any fact about our observations of the world that ceases to be
"paradoxical" if you regard our world as a computer simulation,
or a divine creation, is ipso facto not really paradoxical.

You want naturalists to give a full, detailed explanation
of how and why the world is as it is, and in so far as that's
difficult you say "aha, paradoxes". But for opposing views
you're content to stop when the explanation reaches "computer
simulation" or "mind of God" -- thus leaving all the same
things unexplained as any naturalist might -- but you have
no problem with that. As I say: double standards.

4) These paradoxes are so deep that, to be precise, they are not
paradoxes implied by quantum theory but by quantum observations (i.e.
by observational facts) and hence these paradoxes will remain even if
it were shown that quantum theory is incomplete or wrong.

Again, I think "paradoxes" is a misleading term here. Not
everything counterintuitive is a paradox.

No, we are talking about cases where one deduces mutually
contradictory propositions about the state of objective reality
billions of years ago depending on where we place a measuring device
today, as if what we do today were affecting objective reality's state
billions of years ago. That's certainly paradoxical. (In the context
of the delayed choice experiment the contradictory propositions are
whether the photon behaved as a particle and passed by the left or
right side of the galaxy or else behaved as a wave and passed through
the galaxy as it were.)

Do you seriously believe what you're saying here?

Quantum physics isn't a theory of things that behave sometimes
as particles and sometimes as waves, for which you can ask
"so, this particular thing here, did it behave like a particle
or a wave?". It's a theory of things behaving in a way that
has particle-like and wave-like aspects.

Your two "contradictory propositions" are indeed contradictory.
This involves no paradox: they're just both false, and neither
of them is entailed by the (hypothetical) observations.

Let's defer this until you've shown some willingness to be
more explicit about your worldview and your claims, as per
[a line was accidentally missing from my article here; it said
something like "our earlier discussions."]

Feel free to ask me anything you like, as long as you are able to
respond to your own question in the context of your own ontological
beliefs (assuming the question does make sense in the context of your
own ontological beliefs).

I've already asked you the questions I'm referring to.

--
Gareth McCaughan
..sig under construc
.

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