On 11 Jun 2016, at 21:03, Brent Meeker wrote:
On 6/11/2016 10:14 AM, John Clark wrote:
On Fri, Jun 10, 2016 at 6:11 PM, Brent Meeker
<[email protected]> wrote:
>> It makes no difference if the physics is simulated or
not; a simulated calculation produces real arithmetic not simulated
arithmetic and a simulated brain will produce real consciousness
not simulated consciousness. Bruno's brain works according to the
laws of simulated physics and simulated cyanide with stop that
simulated brain from working and thus the consciousness it produces.
> Exactly - provided you identify "Bruno" as the person we
know in this branch of the multiverse,
But why does cyanide have any effect on any Bruno in any branch
of the multiverse if physics is unrelated to consciousness?
> Bruno just notes that it is commonly assumed that
consciousness is realized by certain computations
And I agree with that, but for computations to exist physics is
required.
That's where you (and I) disagree with Bruno. He takes mathematical
existence, as in, "There exist infinitely many prime integers." or
"There exists a successor to every integer.", as the most
fundamental kind of "exist" and consciousness as derivative,
emerging from all possible computations (which "exist" in arithmetic
and similar axiomatic systems). From conscious thoughts, physics
emerges - not just the physics we observe, but all possible physics
because physics is nothing more than a certain pattern and
consistency of conscious thoughts (perceptions) from which we infer
a physical reality as the best explanation.
I don't think this works because it implies the Boltzmann brain
problem. Bruno admits there is a "white rabbit" problem, but he
thinks he can prove that "white rabbits" and miracles are of measure
zero. I don't think he can, which would make his project not very
interesting since it's easy to explain things by saying everything
happens so THIS is just one of them. A good theory must predict
THIS and NOT THAT.
Mechanism implies observable obeys quantum logic and not any other
logic, and that the subject obeys intuitionist logic, and not any
other logic.
> So if all possible computations exist (and they do in the
mathematical sense)
All correct calculations exist, but all incorrect calculations
exist too, to sort one from the other physics is required.
There are no "incorrect calculations". It's just a universal Turing
machine that runs all one step programs, all two step programs,
etc. Some programs stop. Some programs fall into infinite loops.
Some just keep computing. These are all abstract processes that
"exist" in the mathematical sense. There is no sense in which they
can be correct or incorrect. Among all those infinitely many
computations will be some that instantiate your consciousness and a
physical world of which it is conscious - including other people.
In mathematics you assume some axioms are true and then use them to
build something out of them, but with physics it doesn't matter
what your opinion of the conservation of energy is, if it violates
that principle your perpetual motion machine will let you know
mighty damn quick by not working.
That's in our physics - not in all possible physics. Consider
computer games. They generally implement some internally consistent
physics.
And even if your mathematical axioms are true,
You mean their interpretation applied to something non-
mathematical? Within mathematics axioms are "true" by definition -
although it's just a marker "t" that is conserved by logical
transformations. It's quite different from the correspondence
meaning of "true". This is why Bruno's ideal machine, that he
interviews, which "believes" everything provable in airthmetic can
have false beliefs about the physical world. The first "believes"
in just mathematical provability
Well, it is its own provability. There is as many as there are
machines. I limit myself to interviewing arithmetically sound machine.
. The second "beliefs" is a relation between thoughts and
perceptions and actions.
Belief is "modeled" by Gödel bewesibar, which behaves as described by
G and G*. (G* minus G is the surrational: true but non provable). I
wrote it []p
Then private thought are given by [1]p = []p & p (thank to my
restriction to correct machine!). G* proves []p <-> ([]p & p), but G
does not, which makes the logic differentiating (G and S4Grz). The
observable are given by []p & <>t (<>t means "there is a reality", or
there is an accessible world, somehow (cf Post-Gödel-Henkin's
completeness theorem).
I am OK with your other remarks to Clark.
I have to go, might add comment later.
Bruno
when you use them to derive something there is no way to definitive
know if you made a mistake in doing so.
You mean in your applied interpretation.
But if the physical machine I built doesn't work I know for a fact
I made a mistake in my use of physical principles.
Unless there's a miracle. Right. We use "physical principles" to
mean rules that apply to all times and places (that's why energy and
momentum are conserved, as proved by Emmy Noether). So whenever
some application of principle doesn't work, we just say, "Well, we
must be mistaken about what the physics is." and we modify our
theories. Remember the neutrino. Sometimes we just exclude stuff
from physics because of this. At one time Kepler thought that there
was a mathematical rule that determined the number and orbital
spacing of planets. Now we leave that to chance.
Brent
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