Posted by
Bruce Sherwood on
Jul 08, 2011; 12:19am
URL: http://friam.383.s1.nabble.com/The-Grand-Design-Philosophy-is-Dead-and-Hubris-tp6559131p6560464.html
I'm a physicist, not a philosopher, and I know very little formal
philosophy, but I think in this case what Zeilinger claims is correct,
that measurements have ruled out certain "philosophical" viewpoints on
reality. The specific instance is roughly this (though I hasten to say
that I am not an expert on the new perspectives on quantum mechanics,
nor as I've said knowledgeable in philosophy):
A possible view of microscopic reality is that some particles "have" a
state, only probabilistically determined to be sure, but they have
some state, and an observation determines what that (probabilistically
determined) state is. This view of reality is truly ruled out by
recent experiments, which show that the particles do NOT "have" a
state to be measured, it really really is the case that they take on a
state in the process of measurement.
This is highly counterintuitive. It's the part of quantum mechanics
that Einstein could not accept. The famous Einstein-Podolsky-Rosen
(EPR) paper of the 1930s proved that it you took quantum mechanics
seriously you would lead to absurd predictions, including such things
as a system of particles not already being in a state before being
observed. Since the predictions are absurd, EPR concluded that the
theory of quantum mechanics must be imcomplete.
It was many years before experimenters were able to carry out
experiments to explore these absurdities. When they did, they found
that the absurd predictions of quantum mechanics are in fact what
happens. It is a delicious irony that yet another contribution that
Einstein made to the development of quantum mechanics was to prove
that quantum mechanics cannot be right, thereby stimulating people to
do the experiments to investigate the "absurdities".
Bruce
P.S. I'm now reading an excellent history of the development of
quantum mechanics, "The Quantum Story" by Jim Baggott. Much of this is
familiar, but even one of the tales previously unknown to me was worth
the price of admission (only $10 in Kindle edition). When Bohr created
the Bohr model of the hydrogen atom, in the early 1910s, before
publishing he discussed his ideas with Rutherford. Rutherford, who
cultivated an aw-shucks New Zealand country boy image but who was very
smart, asked, "But if you say that the energy state can drop one, or
two, or three levels, what determines which energy change the atom
experiences? What about causality?"
On Thu, Jul 7, 2011 at 4:21 PM, <
[hidden email]> wrote:
> Bruce Sherwood writes, in relevant part:
>
>> On the other hand, I can recommend highly the popular science book
>> "The Dance of the Photons" by Anton Zeilinger
> [...]
>> At
>> one point in the book he appropriately celebrates measurements that
>> quantitatively address certain aspects of reality that have long been
>> major issues in philosophy (and physics). These recent measurements
>> actually rule out some plausible philosophical stances with respect to
>> reality. It's intriguing that a physical measurement could do that.
>
> Surely it's more than intriguing, it's impossible. Any measurement
> is embedded in a theory (including, at a bare minimum, a theory about
> how the device that performs the measurement functions); all that a
> measurement can do (and it's quite enough, and sometimes--very likely
> in this case--both intriguing and well worth celebrating), with
> regard to a philosophical stance, is provide evidence (possibly,
> as you seem to me to suggest here, categorical evidence) that the
> philosophical stance S and the theory T in which the measurement
> is embedded are incompatible (I want to say "incompossible" but I
> don't think I have the proper credentials to use that word in
> public).
>
> That, at least, is what I think is the correct position to take,
> based on what I've read (and come to believe) about the foundations
> of measurement. But I'm neither a physicist nor a philosopher...
>
> Lee Rudolph
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