On 7/2/2012 6:15 PM, Jason Resch wrote:
On Mon, Jul 2, 2012 at 5:35 PM, meekerdb <meeke...@verizon.net
<mailto:meeke...@verizon.net>> wrote:
On 7/2/2012 2:09 PM, Jason Resch wrote:
To summarize our conversation up to this point:
BM: Do you really not see any difference between tables and chairs and
people
and numbers,
JR: Chairs and people are also mathematical objects, just really
complex ones
with a large information content. This is the necessary conclusion of
anyone
who believes physical laws are mathematical.
BM: No, it's a necessary conclusion of anyone who cannot distinguish a
description from the thing described.
JR: I think the identity of indiscernibles applies: If no distinction
can ever
be made (by observers within a mathematical universe and observers
within a
physical universe) then there is no distinction. You are using
"physical" as an
honorific, but it adds no information.
BM: I can point to a chair and say "This!"
JR: Yes, but how do you know you are pointing to a "physical chair",
rather than
a "mathematical chair"?
BM: I know I'm pointing at a chair. I don't know what at 'mathematical
chair'
is. Can you point out how it is different from a chair?
I think we both agree that if the universe follows mathematical laws,
then
observers can make no distinction between whether they exist in a
platonically
existing mathematical object, or a physical universe. If you agree
with this,
then there is no fundamental ontological difference between chairs,
people, and
numbers, that I can see.
No. The mathematical laws of physics (e.g. the standard model) leave
initial
conditions undetermined,
Which is equivalent to saying every solution to the Schrodinger equation is
true.
It's true that they are solutions. It doesn't follow that they exist.
they assume inherent randomness (symmetry breaking),
No where in the math of quantum mechanics is there anything that suggest collapse of the
wave function.
Except that's the only way to get a definite result. Otherwise your instruments say,
"Well it was probably + and probably -."
A strict interpretation of the the math leaves only MWI (or alternatively, as Ron Garett
points out zero-universes https://www.youtube.com/watch?v=dEaecUuEqfc ).
How did you decide the Born rule wasn't math and wasn't part of QM?
The randomness is explained directly by first person indeterminacy in a reality
containing all possibilities.
Maybe. But it's not clear that it explains the Born rule.
they don't specify why they are the laws of physics instead of some others.
Many physicists hope that they will one day find a reason that our laws of physics are
unique, some justification why the one they find themselves in is the only one that can
be, but this seeming to be a pipe dream. Many physicists dislike anthropic reasoning,
perhaps because it spoils their dream of finding a TOE, but disliking something
shouldn't carry any weight in assessing a theory's validity.
I could say the same about the Born rule and disliking that some things happen
and some don't.
So the ontological difference is that some things exist and some don't.
This
distinction doesn't exist in Platonia: exist=having a consistent
description. In
physics exist=a member of the ontology of the fundamental model.
What's wrong with Platonia being a fundamental model?
No predictive power: everything exists, everything happens.
That's why Everett, to avoid having some randomness, postulated that we
exist in
many copies.
I think there are more reasons than that. Before Everett, QM was extremely ugly, being
the only non-local, non-time reversible, FTL permitting, theory in all of physics. It
is more accurate to say Bohr and Heisenberg inserted collapse into the theory in an
attempt to rescue the single-universe idea. There is nothing in the math of QM to
suggest collapse exists, its addition was entirely artificial, and done to make the
theory seem to fit in with our experience.
What shameful reason! :-)
Everett showed there was no need to do this to fit with our experience, as the theory
itself explains why we don't feel ourselves split.
Others have postulated multiple copies of the universe beyond the Hubble
radius or
in separate inflating spacetimes. Tegmark proposed "all mathematical
structures".
Most of this strikes me as a metaphysical stretch to equate the physical
world with
the Platonic.
Why?
In Platonia everything not self-contradictory exists. There is no
difference
between logical and nomological. Our universe is 'explained' by anthropic
selection
from everything.
And yet another mystery: fine tuning, is explained away.
So do you think there were chairs before there were people? Were there
numbers
before people?
There is no before or after in Platonia. Time is only meaningful to observers inside
certain mathematical structures.
Facing the question: is the universe a mathematical object, or a
physical one,
we must evaluate the two candidate theories as we would any other.
That's not the question. The question is whether all mathematical objects
exist
while only some physical ones do.
No. If all mathematical objects exist, then all things which could be considered
physical universes exist too. What possible difference is there between a physical
universe and a mathematical structure isomorphic to that universe? Should these
extraneous physical universes not be discarded according to Occam?
Along with all the hypothetical ones in Platonia?
In the latter case we need to find which physical ones exist and what is
their
mathematical description.
Does one theory explain more, does one make fewer assumptions, etc. The
existence of the physical universe does not explain the existence of
mathematical objects
I think it does. See William S. Coopers "The Evolution of Reason".
"The formal systems of logic have ordinarily been regarded as independent of biology,
but recent developments in evolutionary theory suggest that biology and logic may be
intimately interrelated. In this book, William S. Cooper outlines a theory of
rationality in which logical law emerges as an intrinsic aspect of evolutionary biology.
He examines the connections between logic and evolutionary biology and illustrates how
logical rules are derived directly from evolutionary principles, and therefore, have no
independent status of their own. This biological perspective on logic, though at present
unorthodox, could change traditional ideas about the reasoning process."
Perhaps rules of logic exist in biology, but the full set of truth concerning the
natural numbers is not contained in biology.
, but the converse is true.
But only in the cheap sense of 'explain' like "God did it." Bruno at least
limits
his fundamental ontology to digital computation, but even this threatens to
'explain' too much.
It is more powerful than "God did it". Given sufficiently powerful computers, we can
verify predictions of the theory.
How. It predicts everything.
Tegmark also believes we can test his theory by seeing statistically how well our
universal constants fit within certain bounds necessary for life to exist.
That faces two big problems. First, it requires some non-arbitrary measure be defined on
'universes'. MML might work. Second, no matter what the measure we know already that
life exists here so finding it to be improbable would prove nothing and neither would
finding it probable - one sample statistics aren't very informative.
Brent
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