On 8/22/2012 9:35 PM, meekerdb wrote:
On 8/22/2012 6:21 PM, Stephen P. King wrote:
On 8/22/2012 7:43 PM, meekerdb wrote:
On 8/22/2012 1:09 PM, Stephen P. King wrote:
On 8/22/2012 2:44 PM, meekerdb wrote:
On 8/22/2012 4:36 AM, Stephen P. King wrote:
Hi Jason,
Nothing "in the theory" suggests that landscapes are a
problem! But that is kinda my point, we have to use meta-theories
of one sort or another to evaluate theories. Occam's Razor is a
nice example... My point is that explanations should be hard to
vary and get the result that one needs to "match the data" or
else it is not an explanation at all. One can get anything they
want with a theory that has landscapes. Look!
http://en.wikipedia.org/wiki/String_theory_landscape
"The string theory landscape or anthropic landscape refers to the
large number of possible false vacua in string theory. The
"landscape" includes so many possible configurations that some
physicists think that the known laws of physics, the standard
model and general relativity with a positive cosmological
constant, occur in at least one of them. The anthropic landscape
refers to the collection of those portions of the landscape that
are suitable for supporting human life, an application of the
anthropic principle that selects a subset of the theoretically
possible configurations.
In string theory the number of false vacua is commonly quoted as
10500. The large number of possibilities arises from different
choices of Calabi-Yau manifolds and different values of
generalized magnetic fluxes over different homology cycles. If
one assumes that there is no structure in the space of vacua, the
problem of finding one with a sufficiently small cosmological
constant is NP complete, being a version of the subset sum problem."
Boom, there it is! The computation problem!
NP-complete problems, or just N-problems, are ones that consume a
lot of computational resources for large problems. But the
required resources are finite and the problems are solvable. So
what's the problem?
Brent
--
It is all about how big the finite problems grow to and whether
or not their demand for resources can be kept up with the load. It
seems to me that Nature would divide up the labor into as many
niches as possible and have a distributed "on demand" system rather
than a single top down computation system.
But you're trying to explain nature. You seem to be assuming nature
as a limited resource in the explanation, thus assuming the thing
you're trying to explain. Bruno at least puts his explanation in
Platonia where the resources are infinite.
Brent
--
Hi Brent,
Of course I am trying to explain Nature, in the sense of building
a ontological theoretical framework. If one starts assuming that
Nature has infinite resources available then one has to ask why is
there a finite world with all the thermodynamic drudgery?
How do you know the world is finite? Most cosmologies allow that the
multiverse is infinite in extent.
Hi Brent,
Good catch! I mean to write "observationally finite". The plurality
of physical worlds allows for the possibility of at least one physical
system to implement any possible computation, so we don't need the "wall
of Platonia" to be tape for the UD.
Bruno does not seem to ever actually address this directly.
Sure he does. The UD only uses finite resources at any give step -
the states are countable and are only executed finitely.
Yes, but with no reference to thermodynamic limits.
It is left as an "open problem". This is why he dismisses the
NP-Complete problem so casually... It is easy to think that way when
thinking in top -> down terms. I am assuming the known physical laws,
particularly thermodynamics and working back down to the ontology.
Physical laws are never 'known'. They are models to explain our
observations.
Another good point. This is where the SSA is useful. I leave that
part of things to the logicians to work out.
If you assume them, then you've assume the model is correct and the
ontology is whatever exists in the model. Why would you do that??
This is Bruno's sin, not mine! Haev you read our
knock-down-drag-out fight over the definition of existence? He defined
existence as contingent on theory, I don't.
He and I are looking from opposite directions. It does not mean that
we fundamentally disagree on the general picture.
There is really only one major disagreement between Bruno and I
and it is our definitions of Universality. He defines computations
and numbers are existing completely seperated from the physical and I
insist that there must be at least one physical system that can
actually implement a given computation.
I think it is probably a consequence of his theory that persons can
only exist when physics exists and vice versa; but it is difficult to
work out the implications (especially for me, maybe not for Bruno).
OK, but if we look at the idea that Pratt proposes, physics drops
out as the maximally consistent set of invariances for a given
collection of observers (monads) that can communicate (aka bisimulate
each other).
This puts the material worlds and immaterial realm on equal
ontological footings and joined together in a isomorphism type
duality relation because of this restriction.
That means you need a material primitive AND an immaterial primitive.
No, only the totality of what exist is primitive. the material and
immaterial emerge as dual and finite aspects. It was Spinoza that first
proposed a version of this idea.
I care more about the philosophical stuff and he the logical stuff.
That a nice division of labor. :-)
Logic is just some rules to keep us from talking self-contradictory
nonsense.
Bah, humbug! ;-) You are giving logic far too little credit.
Brent
--
--
Onward!
Stephen
"Nature, to be commanded, must be obeyed."
~ Francis Bacon
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