Re: [asa] Spooky Action At A Distance: Still Spooky

On Apr 19, 2007, at 6:35 PM, David Opderbeck wrote:

> Here's how I sort of understood it and Rich I think you told me I
> was sort of on track:
>
> Realism: stuff really exists, whether anyone is there to observe
> it or not.

Kind of. Physicists must drive lawyers crazy. :-) Philip Ball put it
better this way. Note: the following URL does not require
subscription to Nature.

http://www.nature.com/news/2007/070416/full/070416-9.html

> By realism, [Zellinger] means the idea that objects have specific
> features and properties [RDB Note: David, think attributes and the
> relation to substance in metaphysics] —that a ball is red, that a
> book contains the works of Shakespeare, or that an electron has a
> particular spin.
> For everyday objects, such realism isn't a problem. But for objects
> governed by the laws of quantum mechanics, like photons and
> electrons, it may make no sense to think of them as having well
> defined characteristics. Instead, what we see may depend on how we
> look.
>
> This notion has been around ever since the advent of quantum
> mechanics in the early twentieth century. The theory seemed to show
> that, in the quantum world, objects are defined only fuzzily, so
> that all we can do is work out the probability that they have
> particular characteristics — such as being located in a specific
> place or having a specific energy.
>
> Allied to this assault on reality was the apparent prediction of
> what Albert Einstein, one of the chief architects of quantum
> theory, called 'spooky action at a distance'. Quantum theory
> suggests that disturbing one particle can instantaneously determine
> the properties of a particle with which it is 'entangled', no
> matter how far away it is. This would violate the usual rule of
> locality: that local behaviour is governed by local events
>
> Einstein could not believe that the world was really so
> indeterminate. He supposed that a deeper level of reality had yet
> to be uncovered — so-called 'hidden variables' that specified an
> object's properties precisely and in strictly local terms.

...

> If the quantum world is not realistic in [a non-local] sense, then
> how does it behave? Zeilinger says that some of the alternative non-
> realist possibilities are truly weird. For example, it may make no
> sense to imagine what would happen if we had made a different
> measurement from the one we chose to make. "We do this all the time
> in daily life," says Zeilinger — for example, imagining what would
> have happened if you had tried to cross the road when a truck was
> coming. If the world around us behaved in the same way as a quantum
> system, then it would be meaningless even to imagine that
> alternative situation, because there would be no way of defining
> what you mean by the road, the truck, or even you.
>
> Another possibility is that in a non-realistic quantum world
> present actions can affect the past, as though choosing to read a
> letter or not could determine what it says.
>
> Zeilinger hopes that his work will stimulate others to test such
> possibilities. "Our paper is not the end of the road," he says.
> "But we have a little more evidence that the world is really strange."

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Received on Thu Apr 19 21:59:41 2007