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

*Kind of. Physicists must drive lawyers crazy. :-)*
**
Indeed. I'd hate to cross-examine a quantum physics guy about a traffic
accident:

Q: What color was the traffic light when the collision happened?

A: It depends.

On 4/19/07, Rich Blinne <rich.blinne@gmail.com> wrote:
>
>
> 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 Fri Apr 20 09:23:57 2007