Bruno Marchal wrote:
On 18 May 2015, at 02:31, Bruce Kellett wrote:
LizR wrote:
On 17 May 2015 at 11:44, Bruce Kellett
<[email protected] I can see that computationalism
might well have difficulties
accommodating a gradual evolutionary understanding of almost
anything -- after all, the dovetailer is there in Platonia
before anything physical ever appears. So how can consciousness
evolve gradually?
This is the tired old misunderstanding of the concept of a block
universe. It's as though Minkowski never existed.
OK. Explain to me exactly how the block universe ideas work out in
Platonia.
I thought I saw an answer by Liz, but don't find it.
No, Liz only snipes from the sidelines.....she does not answer
substantive questions.
I am not sure that the "block physical universe" ideas work out in
Platonia, although block physical multiverse appearance might be
explainable by the rather canonical "all computations", which is offered
once we agree that 2+2 = 4, or any theorem of RA, is true independently
of him/her/it.
The block multiverse could well be a different concept from the block
universe of the Minkowskian understanding of special relativity.
The question arose in a discussion of the possibility of an evolutionary
understanding of consciousness. This does not, on the face of it, appear
to sit terribly easily in comp, since comp starts from the individual
conscious moment or moments, and seeks to understand physics as somehow
emergent from the statistics of all such instantiations of this set of
computations in the UD. This does not appear to relate easily to an
account of times before and after the existence of that particular
consciousness.
Part of my problem is that the UD does not execute any actual program
sequentially: after each step in a program it executes the next step of
the next program and so on, until it reaches the first step of some
program, at which point it loops back to the start. So if the conscious
moment is evinced by a logical sequence of steps by the dovetailer, it
does not correspond to any particular program, but a rather arbitrary
assortment of steps from many programs. Of course, given that all
programs are executed, this sequence of steps does correspond to some
program, somewhere, but not necessarily any of the ones partially
executed for generating that conscious moment.
There is also a question as to whether this sequence of computational
steps generates one conscious moment -- of some shorter or longer
duration (duration being in experienced time, since the computations are
timeless) -- or whether a whole conscious life is generated by a
continuous sequence of steps, or whether the whole history of the world
that contains that consciousness (and all other conscious beings, past,
present, and future) are generated by the same (extraordinarily long)
continuous sequence of computational steps.
If the idea is something along the lines of the latter possibility, then
the block universe might well be the result. The problem then, of
course, is that any particular consciousness will be generated an
indefinitely great number of separate times for each time this whole
universe is generated. This, of course, is the Boltzmann brain problem,
and I do not think you have adequately addressed this.
Of course, it is a poisonous gift, as it leads to the necessary search,
for the computationalist, of a measure on the border of the sigma_1
reality.
It is long to explain, but you might appreciate shortcuts, as the
sigma_1 arithmetical reality emulates all rational approximations of
physical equations, and so, abstracting from the (comp) measure problem
temporarily, you can make sense of relative local block universe in that
reality, as that part of the arithmetical reality mimics the physicists
block universe or universes (perhaps only locally too).
Generating all rational approximations of physical equations is not
going to get you a block universe -- or any sort of universe, for that
matter. The equations of physics describe the behaviour of the physical
world, they are not that physical world -- map and territory again.
Of course such shortcuts might not have the right measure, and so we
need to use a vaster net.
My point is that if our brains or bodies are Turing emulable then they
are Turing emulated in a small part of the arithmetical reality. The
first person points of view gives an internal perspective which is much
complex, in fact of unboundable complexity, but with important
invariants too.
In the technic parts I exploit important relations between the sigma_1
truth, the sigma_1 provable and the (with CT) intuitively computable.
I can explain, if you want, but my feeling is that you don't like the
idea (that the aristotelian materialist dogma can be doubted), nor does
it seems you are ready to involve in more of computer science.
But if you don't study the work, you should try to not criticize it from
personal taste only. I can't pretend liking all consequences of comp,
but that is another topic. Science is NOT wishful thinking, a priori.
No, but I am not critical of comp because it clashes with any particular
metaphysical ideas. I am critical because I do not think it makes sense
at a deep and fundamental level -- and because it is clearly falsified
by everyday observations -- such as the role of the physical brain in
consciousness, and the physical explanation of that role via evolution.
Also, it is not a matter of a willingness to work through all the
details of computer science. If you cannot explain your ideas without
resorting to the sort of jargon that you typically use, the only
conclusion that I can draw is that you do not really understand what you
are talking about. I forget who it was that said something along the
lines that it is only in explaining your ideas to a novice that you ever
get to really understand them.
And in this context, I refer to comment you made in another post: "Modal
logic is the tool. Modal logic is to self-reference what Tensor analysis
is the General Relativity."
I think that I could quite readily explain the basic ideas and results
of general relativity to a complete novice without ever mentioning
tensor analysis: if I couldn't, I would take that as evidence that I
didn't really understand what I was trying to explain.
Bruce
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