Re: [Fis] Fw: Responses

2014-01-21 Thread Robert E. Ulanowicz

 The reason of being of information, whatever its content or quantity, is
 to be used by an agent (biological or artificial).

Dear Christophe,

In making this restriction you are limiting the domain of information to
communication and excluding all information that inheres in structure
per-se. John Collier has called the latter manifestation enformation,
and the calculus of IT is quite effective in quantifying its extent.
Perhaps John would like to comment?

Cheers,
Bob U.


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[Fis] New Year Lecture wrap-up

2014-01-21 Thread Dino Buzzetti
Dear Hans,

Thank you very much again for your lecture and your
subsequent comments and replies.  I dare posting a new
comment as an aftermath to your wrap-up and to Pedro's
official closure.  But I am sure you agree with me, that the
matter cannot be settled yet and that a continuation of the
discussion is a sign of the fruitfulness of your lecture.  As
a matter of fact, when I received Pedro's official closure
announcement I was a little disappointed because I had
been gathering some evidence in support of a previous
comment of mine, which probably was not clear enough.
I would not like to bother you any more, but since you
mention the usefulness of a philosophical outlook, here
is a philosophical observation I was able to find.

According to Jules Vuillemin (*Necessity or Contingency*,
Stanford CA, CSLI Publications, 1996), “probability in the
classical sense,” as is well known, is “relative to our ignorance
only” (p. 261), but “probability amplitude is something
altogether different” (264). For “when physicists today make
reference to [...] probability amplitudes [...] they indeed
allude to second order probabilities” (167). Therefore, the
distinction “between a probability and a probability amplitude”
entails a “new distinction in the history of modal notions,”
a distinction that Vuillemin describes in the following way:

“Classical physics was content with the opposition 'This particle
passes through A' versus 'This particle has the probability π
of passing through A'. This opposition has nothing to do with
ontology: it incorporates what is due to our ignorance into the
determination of natural phenomena. Instead of attributing
a property or magnitude to a physical system, we attribute it
a disposition or propensity to have that property or magnitude.
Probability measures that disposition or propensity that belongs
to the system in act. A probability amplitude is something
altogether different. We can compare it to an embryonic
probability as the inventors of the infinitesimal calculus
compared the moment of motion to an embryonic motion
that an integration would bring to a state of whole motion.
But the comparison limps. For the probability amplitude,
which is generally a complex quantity, does not figure among
the elements of reality. To obtain a probability we must multiply
two conjugated probability amplitudes. This means that, when
we attribute that amplitude to a system, it is attributed neither
as an actual property or magnitude nor as an actual disposition
or propensity to having such property or magnitude, but as a
purely virtual disposition or propensity to having it. The second-
order potentiality, as it were, thus put into play is no longer the
measure of an ignorance that might have some chance of being
only provisional. It is physical. It describes nature.” (264-65)

This is just the conclusion of a long-winded argument, but if
Vuillemin is right, then, the interpretation of a superposition
of probability amplitudes cannot be Bayesian, or “relative to
our ignorance only.” (261)

As S. Barry Cooper observes (
*Definability in the Real Universe*, http://arxiv.org/abs/1109.1416 ), “the
Laplacian
model has a deeply ingrained hold on the rational mind.
For a bromeliad-like late flowering of the paradigm we tend
to think of Hilbert and his assertion of very general expectations
for axiomatic mathematics. Or of  the state of physics before
quantum mechanics.”  From this point of view, QBism might
be described, to use Barry Cooper's own words, as “a defensive
response to an uncompleted paradigm change” (p. 4).

Kind regards,  -dino buzzetti




On 18 January 2014 18:47, Hans von Baeyer henrikrit...@gmail.com wrote:

 Dear Friends: In keeping with the message of my lecture, that knowledge of
 the world is based on the ensemble of individual experiences, more than on
 assumed objective, actual properties of an external reality, I will tell
 you about my experiences of writing and discussing the New Year Lecture. I
 enjoyed the entire process enormously, and wish once more to applaud Pedro
 for inventing this new tradition!

 Even as I started this email I learned something that piqued my interest.
  Gregory Bateson was quoted: Kant argued long ago that this piece of chalk
 contains a million potential facts (Tatsachen) but that only a very few of
  these become truly facts by affecting the behavior of entities capable of
  responding to facts.  Google.de informed me that Tatsache is probably an
 18th century translation of the English matter of fact. Tat is a deed,
 a factum, something done or performed, while Sache means a thing or a
 matter.  This tenuous etymology connects factuality with action rather than
 with some intrinsic essence. Kant's words affecting, behavior and
 responding are QBist to the core. More and more I realize that philosophy
 matters. Chris Fuchs, the chief spokesman for QBism, is among the rare
 physicists who give credit to philosophers for the contributions 

[Fis] Probability Amplitudes

2014-01-21 Thread Hans von Baeyer
Dear Dino and friends, thanks for bringing up the issue of probability
amplitudes.  Since they are technical tools of physics, and since I didn't
want to go too far afield, I did not mention them in my lecture.  The
closest I came was the wavefunction, which, indeed, is a probability
amplitude.  In order to make contact with real, measurable quantities, it
must be multiplied by its complex conjugate. This recipe is called the Born
rule, and it is an ad hoc addition to the quantum theory. It lacks any
motivation except that it works.

In keeping with Einstein's advice (which he himself often flouted) to try
to keep unmeasurable concepts out of our description of nature, physicists
have realized long ago that it must be possible to recast quantum mechanics
entirely in terms of probabilities, not even mentioning probability
amplitudes or wavefunctions. The question is only: How complicated would
the resulting formalism be?  (To make a weak analogy, it must be possible
to recast arithmetic in the language of Roman numerals, but the result
would surely look much messier than what we learn in grade school.)
 Hitherto, nobody had come up with an elegant solution to this problem.

To their happy surprise, QBists have made  progress toward a quantum
 theory without probability amplitudes.  Of course they have to pay a
 price.  Instead of unmeasurable concepts they introduce, for any
 experiment, a very special set of standard probabilities (NOT AMPLITUDES)
 which are measurable, but not actually measured.  When they re-write the
 Born rule in terms of these, they find that it looks almost, but not quite,
 like a fundamental axiom of probability theory called Unitarity.  Unitarity
 decrees that for any experiment the sum of the probabilities for all
 possible outcomes must be one. (For a coin, the probabilities of heads and
 tails are both 1/2.  Unitarity states 1/2 + 1/2 = 1.)


This unexpected outcome of QBism suggests a deep connection between the
Born rule and Unitarity. Since Unitarity is a logical concept unrelated to
quantum phenomena, this gives QBists the hope that they will eventually
succeed in explaining the significacne of the Born rule, and banishing
probability amplitudes from quantum mechanics, leaving only (Bayesian)
probabilities.

So, I'm afraid dear Dino, that the current attitude of QBists is that
probability amplitudes are LESS fundamental than probabilities, not MORE.
 But the story is far from finished!

Hans


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Re: [Fis] Probability Amplitudes

2014-01-21 Thread Dino Buzzetti
Dear Hans,

Thank you for your explanation about probability amplitudes,
that clarifies a lot.  My only worry was about the *epistemological*
implications of quantum mechanics in its standard formulation,
that in my opinion point to a paradigm shift, which is felt not only
in this domain, but in all fields where *emergent* phenomena are
accounted for—a process that I thought was hinted to by Wheeler's
famous words It from Bit, that I remember reading for the first
time precisely in your book on information.  That's the ground for
expressing my worry that reverting to classical probability theory
might entail a drawback to this decisive epistemological turn.

But I might misunderstand the whole story, that is certainly not
over yet  :-)  -dino



On 22 January 2014 00:21, Hans von Baeyer henrikrit...@gmail.com wrote:

 Dear Dino and friends, thanks for bringing up the issue of probability
 amplitudes.  Since they are technical tools of physics, and since I didn't
 want to go too far afield, I did not mention them in my lecture.  The
 closest I came was the wavefunction, which, indeed, is a probability
 amplitude.  In order to make contact with real, measurable quantities, it
 must be multiplied by its complex conjugate. This recipe is called the Born
 rule, and it is an ad hoc addition to the quantum theory. It lacks any
 motivation except that it works.

 In keeping with Einstein's advice (which he himself often flouted) to try
 to keep unmeasurable concepts out of our description of nature, physicists
 have realized long ago that it must be possible to recast quantum mechanics
 entirely in terms of probabilities, not even mentioning probability
 amplitudes or wavefunctions. The question is only: How complicated would
 the resulting formalism be?  (To make a weak analogy, it must be possible
 to recast arithmetic in the language of Roman numerals, but the result
 would surely look much messier than what we learn in grade school.)
  Hitherto, nobody had come up with an elegant solution to this problem.

 To their happy surprise, QBists have made  progress toward a quantum
 theory without probability amplitudes.  Of course they have to pay a
 price.  Instead of unmeasurable concepts they introduce, for any
 experiment, a very special set of standard probabilities (NOT AMPLITUDES)
 which are measurable, but not actually measured.  When they re-write the
 Born rule in terms of these, they find that it looks almost, but not quite,
 like a fundamental axiom of probability theory called Unitarity.  Unitarity
 decrees that for any experiment the sum of the probabilities for all
 possible outcomes must be one. (For a coin, the probabilities of heads and
 tails are both 1/2.  Unitarity states 1/2 + 1/2 = 1.)


 This unexpected outcome of QBism suggests a deep connection between the
 Born rule and Unitarity. Since Unitarity is a logical concept unrelated to
 quantum phenomena, this gives QBists the hope that they will eventually
 succeed in explaining the significacne of the Born rule, and banishing
 probability amplitudes from quantum mechanics, leaving only (Bayesian)
 probabilities.

 So, I'm afraid dear Dino, that the current attitude of QBists is that
 probability amplitudes are LESS fundamental than probabilities, not MORE.
  But the story is far from finished!

 Hans






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Re: [Fis] Probability Amplitudes

2014-01-21 Thread Joseph Brenner
Dear Hans and Dino,

This is a direct question to both of you, to which I have not found a clear 
answer: are value and amplitude the only parameters that have been assigned to 
probability?

In my theory, the changing value of actuality and potentiality of specific 
antagonistic process elements are probability-like in not including 0 and 1, as 
I have said. Can, in addition, probabilities have some vector-like properties, 
that is, include a /direction/? 

This concept would be moving toward (and past) Dino and away from Hans . . .

Your comments and those of others would be welcome.

Best wishes,

Joseph
  - Original Message - 
  From: Dino Buzzetti 
  To: Hans von Baeyer ; fis 
  Sent: Wednesday, January 22, 2014 3:53 AM
  Subject: Re: [Fis] Probability Amplitudes


  Dear Hans, 


  Thank you for your explanation about probability amplitudes, 

  that clarifies a lot.  My only worry was about the *epistemological* 

  implications of quantum mechanics in its standard formulation, 

  that in my opinion point to a paradigm shift, which is felt not only 
  in this domain, but in all fields where *emergent* phenomena are 
  accounted for—a process that I thought was hinted to by Wheeler's 
  famous words It from Bit, that I remember reading for the first 
  time precisely in your book on information.  That's the ground for  
  expressing my worry that reverting to classical probability theory 
  might entail a drawback to this decisive epistemological turn.   


  But I might misunderstand the whole story, that is certainly not 
  over yet  :-)  -dino





  On 22 January 2014 00:21, Hans von Baeyer henrikrit...@gmail.com wrote:

Dear Dino and friends, thanks for bringing up the issue of probability 
amplitudes.  Since they are technical tools of physics, and since I didn't want 
to go too far afield, I did not mention them in my lecture.  The closest I came 
was the wavefunction, which, indeed, is a probability amplitude.  In order to 
make contact with real, measurable quantities, it must be multiplied by its 
complex conjugate. This recipe is called the Born rule, and it is an ad hoc 
addition to the quantum theory. It lacks any motivation except that it works.


In keeping with Einstein's advice (which he himself often flouted) to try 
to keep unmeasurable concepts out of our description of nature, physicists have 
realized long ago that it must be possible to recast quantum mechanics entirely 
in terms of probabilities, not even mentioning probability amplitudes or 
wavefunctions. The question is only: How complicated would the resulting 
formalism be?  (To make a weak analogy, it must be possible to recast 
arithmetic in the language of Roman numerals, but the result would surely look 
much messier than what we learn in grade school.)  Hitherto, nobody had come up 
with an elegant solution to this problem.


  To their happy surprise, QBists have made  progress toward a quantum 
theory without probability amplitudes.  Of course they have to pay a price.  
Instead of unmeasurable concepts they introduce, for any experiment, a very 
special set of standard probabilities (NOT AMPLITUDES) which are measurable, 
but not actually measured.  When they re-write the Born rule in terms of these, 
they find that it looks almost, but not quite, like a fundamental axiom of 
probability theory called Unitarity.  Unitarity decrees that for any experiment 
the sum of the probabilities for all possible outcomes must be one. (For a 
coin, the probabilities of heads and tails are both 1/2.  Unitarity states 1/2 
+ 1/2 = 1.)


This unexpected outcome of QBism suggests a deep connection between the 
Born rule and Unitarity. Since Unitarity is a logical concept unrelated to 
quantum phenomena, this gives QBists the hope that they will eventually succeed 
in explaining the significacne of the Born rule, and banishing probability 
amplitudes from quantum mechanics, leaving only (Bayesian) probabilities. 


So, I'm afraid dear Dino, that the current attitude of QBists is that 
probability amplitudes are LESS fundamental than probabilities, not MORE.  But 
the story is far from finished!


Hans



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