I think you hit a central point in this discussion as well is in the one
about Bell's inequality, but I (and SOA) would give it the arguments a
slightly different twist.
You said in reply to Ted:
>Why do we think that such a thing as quantum gravity should exist at
> all? The only reason is again the Copenhagen dogma about the
> completeness of QM. If one assume that QM is not complete at all, so it
> is not fundamental theory (and if one be even more provocative and
> assume that QFT is neither fundamental and complete theory), then there
> is no reasons to think that such a thing as quantum gravity exists.
> May be the real fundamental theory is purely classical and QM is just an
> approximation of such a theory.
I think we have to go ever deeper below the surface of knowing and ask why
we do say that quantaum gravity exists - or that any phenomenon exists for
that matter. I mean after all it make a lot of difference if one says a
concept exists as a convention or in "reality." If we cannot be clear about
what type of existence we refer to then we must leave all questions
unsettled.
If we cannot dig out the essence of what it means for something
ontologically "exist" then all our talking about "ontological existence" is
meaningless in principle - and bewildering. To my my this is what Bohr
refers to when he denies ontology - but he don not deny concepts to exists
by CONVENTION. The problem here is that conventional existence cannot be
proved by experimental means - and this presents a big problem to physics -
since many physicists seem to ask for an experimental proof of a
convention for its acceptance, which clearly is impossible.Bohr claim goes
further as he claimsthat ANY CONCEPT used in physics (and all sciences
- including mathematics andlogics) I would say - is a mattter of
convention.
This is why ontology is forbidden to Bohr's mind and my.
The force of gravity - as any force - is just an expanandum. In Newton's
classical definition F = ma; F is just an abstraction of feel explaining why
a "body" defined by its visal feel of mass change its velocity in a
visual impression, which is also a feel - however all felt by the same
subjective observer. F=ma is a relation of subjective feels (Newton's) that
is so clever that it gained the consensual acceptance as a model in physics.
F, m,
or a in this expression do in not explain themselves in any way or take
their places in an ontological domain unless we place them there BY
CONVENTION.
So classical physics cannot explain gravity and why should QM or QFT be
different? The problem is, to mymind,that we, as part of a scientific
culture most influenced by Plato maybe,
have misleading expectations. Some expect a theory to be able to explain the
"essence of a phenomenon" - which simply is to ask to much. If
ontology is forbidden - then also the "what is"-question is forbidden -
for the simple reason there is no answer to be found. The answer "what is
gravity" has no ontological answer - we can only provide an answer by
providing by reference to a model (of convention), which is an
epistemological answer. So
it seems your assumtion that QM and
QFT is neither fundamental or complete theory is a very useful one.
Futhermore this assumtion is useful for any theory - in case one expects an
ontological explanation or proof from a theory. This is impossible and today
even matematicians
know that we are not able to prove anything with certainty. Accordingly then
there is no reasons to think that such a thing as quantum gravity exists (in
its ontological sense) - since ontological existence is a misconception.
What exists is
personal experience - and Bohr is very clear on this point. Ontology is
forbidden - as is the idea of ontological existence. If something exists ...
it exists in the mind of a knower (not necessarily an observer). If a
society of knowers use a concept like gravity, mass or acceleration in
consensus they have decided that the idea of gravity, mass and acceleration
is useful in describing the physicist's experience - this is the al and the
end. We cannot come further (deeper) and we need not come futher - because
predictions effectively works on personal experience - and "featureless"
experience.
After all the term force of gravity is just a way to connect the everyday
man to
his very experince of feels - and this is good since it make him understand
mathematics - but does in no way give him (or other human beings) what is
the essence of "force". We must be content with that we by convention can
provide a common model because then we can communicate and use our
experience in a
way that is scientific and moreover virtually MAKE SENSE.
Best wishes at all
Arne
kjellman@dsv.su.se
_______________________________________________
fis mailing list
fis@listas.unizar.es
http://webmail.unizar.es/mailman/listinfo/fis
Received on Wed Jun 14 10:29:05 2006
