Dear Hans and All,
This is a very useful form of responses, which enables further directed
comments. I start with Lars', which is perhaps as Hans says crucial:
Lars -- How does QBism differ from Copenhagen? This is a crucial question. It
differs not at all in the formalism, and only subtly in the interpretation.
Many users of quantum mechanics regard the wavefunction as a real property of
an electron. They talk about the wavefunction in the same way you might say
the speed of the car. They must then deal with perennial problems such as
action-at-a-distance and the collapse of the wavefunction. QBists regard the
wavefunction the way Bruno de Finetti regarded probability, when he wrote, in
caps, PROBABILITY DOES NOT EXIST. I think he meant that the probability of a
coin falling heads is not a measurable property of a coin. All it is is a
personal belief of how much an agent should bet. And that belief changes
instantly and locally when you make a measurement, or hear that someone else
has made one.
Joseph (New) -- One does not learn much about the way things are by reference
to simple, binary phenomena (coins) or more complicated versions in game theory
(profit-loss). All these have little to do with processes, such as information,
which embody complex oscillations between presence and absence, non-meaning and
meaning, and so on.
Some people call the the Copenhagen wavefunction ontic, the QBist one epistemic.
Joseph (New) -- This is an extremely important statement by Hans whose
consequences, IMHO, should be discussed as they relate to information. We all
agree that one cannot surf on ontic Copenhagen waves, while we 'know what we
know'. But ontic positions, when some of the deficiencies of the original
Copenhagen interpretation are corrected, have a lot to say about /how/ we know,
what the properties of what we know are, and how the two are interrelated.
Rather than saddle QBism with an ignorantist position, I would like to see it
expand to include this relation.
Gordana -- I am out of my depth in a discussion of
phenomena/noumena/Dinge-an-sich. But when I agree that the Higgs exists out
there in the world, I am sure it's not an object like a marble, but a symbol
for a collection of experiences that many people have had, and have discussed,
and codified, so that if they perform another experiment where it might play a
role, they can be prepared with betting odds for what they might experience
next.
Joseph (New) - - That it is a collection of experiences does not exclude that
it is an object, or better process, of a kind other than a 'marble'. As such,
in discussing it, we can go beyond binary game metaphors.
Joseph -- the electron is a point means that no experiment to date has
found evidence for a finite size. In the theory (quantum electrodynamics)
there is no room for any parameter with dimensions of length, although there
are mass, charge, spin, and magnetic moment. When you introduce a finite size
into the theory, it makes wrong predictions. (This is not true for protons, for
example.)
Joseph (New) -- Same as above. The fact that an electron does not have a
'finite size (diameter)' does not mean that is does not exist objectively. It
is fuzzy with a 'size' greater than the Planck length and less than that of a
hadron.
The gravitational field lives in 3D was not supposed to deny that Einstein's
elegant formulation treats time as a fourth dimension. But a quantum field
is an altogether different and much more complicated beast which lives in
infinite dimensions, and has no analog whatever in our everyday human world.
Joseph (New) -- In my opinion, 1) current theories of gravity add more to
Einstein's original number of four dimensions to the gravitational field; 2)
current quantum theories do not saddle the quantum field with a mathematical
infinity. There are no such infinities in nature. That there is no analog of
the quantum field at the macroscopic level does not mean that there are no
isomorphisms between levels. One aspect is that of the couple duality -
self-duality as I mentioned earlier.
Having a proper view of physics among the many possible is critical to placing
information theory on a sound basis. I have proposed Logic in Reality as one
way of giving meaning to the statement that energy and information processes
are non-separably related and how they are related. Are there others?
Thank you and best regards,
Joseph___
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