Is the uncertainty principle culturally deranging?

[Prashant Kumar]

I'll see your Derrida and raise you a Borges.

P.

On 3 August 2012 01:02, Paul Mackin <mackin.paul at verizon.net> wrote:

>  On 8/1/2012 9:47 PM, Prashant Kumar wrote:
>
> The uncertainty principle as mentioned (as opposed to used) in
> postmodernism and elsewhere is not the physicist's uncertainty principle.
> If one misunderstands something aggressively enough it takes on a life of
> its own.
>
>  Just for clarity, I should differentiate between two versions of the HUP
> which have popular currency, and are (consequently) almost always
> conflated.
>
>  Some people will tell you that the HUP forbids you from exactly
> specifying position and momentum (think of momentum as how much something
> hurts when it hits you); if I have a quantumball, I can't get both pieces
> of information at a given instant. A more useful way of restating this is
> that I can't *measure* both simultaneously. If I measure position, then
> momentum, I don't get the same results as if I measure momentum then
> position. This isn't true in classical physics.
>
>  In QM we don't know exact values of things like position and momentum.
> Instead we work with probability distributions. HUP tells you that if you
> know one quantity with some (statistical) degree of specificity, then the
> other quantity is limited in a particular way. If I give you the position
> of our quantumball exactly, you will have no idea of its momentum. This is
> a consequence of the way wavefunctions work. It does *not* mean that our
> knowledge is imperfect or incomplete. It means that there is no more there
> to know. This is the modern understanding (modulo technical mathematical
> caveats).
>
>  Usually something called Heisenberg's (the guy was prolific) microscope
> enters the picture at this point. This thought experiment tries to imagine
> the actual *process* of measurement, and see whether we can find some
> physical reason for HUP. At the time of its formulation, the only known way
> to measure a quantum state was to subject it to photons, measure it
> directly or indeed just get in there and rustle around till you got what
> you came for, leaving the quantum state spent and shivering under the
> sheets. The argument was that the act of measurement, and the requisite
> interaction, was responsible for the uncertainty principle: you changed the
> state by mucking round with it, so you're not going to get exact results.
>
>  Problem is, today we know there is a class of measurements which are
> known as *interaction-free, *you get information seemingly for free*,
> without* directly addressing the state*. *And these measurements are also
> subject to the HUP. This is a particularly dark kind of magic and I won't
> go into it, but if you're interested check out the Elitzur-Vaidman bomb
> tester. Interaction-free measurements have actually been performed in a lab.
>
>  So if someone at a party tells you that the uncertainty principle
> implies something about our knowledge of the universe, fundamental
> inconsequentiality of human endeavour etc., you should shank them with your
> champagne flute, then patiently explain the failure of Heisenberg's
> microscope.
>
>
> Thanks, Preshant.  Helpful explanation.
>
> If people want to talk about the uncertainty of knowledge, they still have
> "il n'y a pas de hors-texte" to fall back on.
>
> P
>
>
>
>
>
> On 2 August 2012 07:10, Paul Mackin <mackin.paul at verizon.net> wrote:
>
>>  On 8/1/2012 4:33 PM, Madeleine Maudlin wrote:
>>
>> Oh der*anging*.  Mr. Kohut is certainly *that*.  I would never use that
>> word though, or any deranged derivative there, hem, of.  If I did it would
>> be in the best sense possible, which for me would be exceedingly *good*.
>>
>>
>>  Vidal claims he was using the word, if not necessarily in the best sense
>> possible, not the worst sense either.
>>
>> Writing of the author of GR:  "Only a physicist who wrote good prose
>> could tell us if, say, Heisenberg’s famous and culturally deranging
>> principle is correctly used in these many, many pages."
>>
>>
>>
>> P
>>
>>
>>  Does anybody write here?  I just got an email, who knows why I'm on
>> their list, I haven't tried to publish anything in years, from a place
>> called AuthorHouse, subject says Publish today and get a no-cost bump-up.
>>  So I guess it's free, today, if you want to get published.  I'm currently
>> stuck on page 400 hell with no end in sight.  432.  What is it about 400?
>>  The Moon is 400 times smaller than the Sun and 400 times closer to it than
>> the Earth, or something.  Bumping-up, m
>>
>> On Wed, Aug 1, 2012 at 2:58 PM, Paul Mackin <mackin.paul at verizon.net>wrote:
>>
>>>  On 8/1/2012 10:23 AM, Prashant Kumar wrote:
>>>
>>> Yes.
>>>
>>>
>>>
>>> but not pejoratively so I hope
>>>
>>> P
>>>
>>>
>>>
>>>  P.
>>>
>>> On 1 August 2012 23:52, Paul Mackin <mackin.paul at verizon.net> wrote:
>>>
>>>>
>>>>
>>>> http://www.nybooks.com/articles/archives/1976/oct/28/plastic-fiction-3/
>>>>
>>>
>>>
>>>
>>
>>
>
>
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