On 10 May 2017, at 07:28, David Nyman wrote:
On 10 May 2017 3:04 a.m., "Bruce Kellett"
<[email protected]> wrote:
On 10/05/2017 12:41 am, Bruno Marchal wrote:
On 09 May 2017, at 09:36, Bruce Kellett wrote:
Yes, it does seem that we are each outlining positions and
arguments that do not necessarily intersect at many points. I will
try and answer some of your more direct questions. Why do I take
the view that "the experience of a unique agent such as the one
analogised by Hoyle or Barbour would be dominated by random events
rather than the order imposed by the predominance of a robust
physical-computational mechanism." The reason is that I am
starting from a slightly different perspective -- I am looking at
the UD as a system in its own right. The questions seem to concern
statistics extracted from the behaviour of this system. When
approaching such a question, I tend to look on the thermodynamic,
or statistical mechanical properties of such a random system. If
you take the UD, with its completely random operation over all
possible (computer) programs, the analogy that comes to mind is
that of thermal equilibrium -- every possible state has equal
probability of occurring. Ergodic theory is possible also
relevant, but I have less familiarity with that, so tend to stick
to ideas deriving from Boltzmann. Given this state of thermal
equilibrium, states of some order -- such as conscious moments --
are going to be unlikely, and fluctuations that give single
conscious moments are overwhelmingly more likely than more
extended fluctuations that give a sequence of related conscious
moments.
Not sure I understand. The UD is not random at all.
The sequence of computational steps may be deterministic, but the
net result in the infinite UD is random. Think of Boltzmann's case,
a gas of a very large number of molecules. The molecules move and
interact according to entirely deterministic laws, but ergodic
theory indicates that after a suitable time, the motions of the
molecules will be effectively random. I think the same must happen
with the dovetailer: although each program is deterministic, the
dovetailing of infinitely many such programs means that sequences of
individual steps are random (or indistinguishable from random).
What is random is the First Person Indeterminacy on all the stable
continuations of my states, as seen by the first person, so the
first thing to do is to get a mathematical theory of the first
person (which I take to Theaetetus, as Gödel's incompleteness makes
it work again, again Socrates opinion).
Given also the insight from Barbour that each conscious moment --
time capsule -- is self contained,
I am not sure that such an intuition is correct. A conscious moment
needs at least two universal numbers, but in fine relies on an
infinity of them. Nor do I conceive such a thing as an observer
moment. the semantic of all first person view (the modalities with
"& p" attached to them) are topological. Consciousness is always on
an interval, not on a discrete point in some time frame.
I was deliberately vague in specifying what was meant by a
"conscious moment". I doubt that it is of zero duration, but the
duration is indeterminate. Beside, there is no concept of time in
the UD, so it is hard to say what a conscious moment might actually
be -- some sequence of computational steps, perhaps -- but how many?
A time capsule is certainly self-contained. Whether these overlap or
not to give a sense of continuity is another question, and would
seem merely to extend the notion of a conscious moment in time
somewhat -- but what is time?
and in itself, a complete explanation of our conscious experience,
the computations that pass through our conscious moments are
overwhelmingly likely to be random, with just small fluctuations
from equilibrium. I.e., single conscious moments with no
consistent continuation-- going from white noise to white noise.
This is, of course, Russell's Occam catastrophe in a different
guise. The experience of the agent is not random -- they
experience conscious moments with a seemingly coherent chain of
memories giving a comprehensible history -- but there is no reason
to suppose that these memories are veridical.
They will be more or less plausible, with respect to the normal
computations, if they exist of course, but they have to exist if
computationalism is correct.
The computations underlying the conscious moment have, then, to also
compute the physics that renders the memories veridicial -- but that
involves memories stretching back tens of years. An awful lot of
computations have to come together to make consciousness that means
anything. Making the probability in the sea of random noise smaller
and smaller all the time.
Sure, but probability of what and from whose point of view? Aren't
you continuing to think of this principally from a third person
perspective (actually merely an abstract "view from nowhere")? Yes,
from that impossible point of view there is no conceivable search
function that could locate the critical computational structures of
this sort; under this interpretation their measure is effectively
zero. Nevertheless we know their presence is in fact assured by
assumption. In point of fact these computations have the recursive
characteristic of exploding into an infinite fractal-like
structure of extremely high frequency (as Brent has recently put it)
which would give them in a certain and possibly critical sense a
highly robust and non-trivial structure. But the key point is that,
on the basis of Bruno's theory of computational subjectivity (again,
implied by assumption of the CTM), they must be *self-locating* from
the first person perspective. This is the key difference that would
unleash the creative subjective potential of the torrential output
of the UD, as distinct from Borges's merely alphabetical Babel which
can only ever be a zero-informational wasteland.
But how can we assess "probability" in such a context? Very
controversial point as you know. Nonetheless, Hoyle gives us an
intuitive heuristic that allows us to think of this in what is
effectively a quasi-frequentist manner (i.e. the relative subjective
frequency of "encountering" any particular momentary perspective
over any finite segment of their abstract serialisation). This
heuristic has both absolute (in the first instance) and relativising
(in the second) self-sampling characteristics. If we think of it in
something like this intuitive way (which IMO is the absolute key to
the argument) then the justification of a measure assessed in the
above manner has to lie in the direction of understanding how and
why the "organised" threads of narrative subjectivity shouldn't be
effectively swamped in a sea of subjective chaos because of
competition from "pathological" quasi-narrative fragments. I've
tried to pump our collective intuition with various analogies to
suggest why this wouldn't necessarily be the case, to supplement
Bruno's more rigorous logico-mathematical argument. Hardly
conclusive of course but the intention is principally to encourage a
harder look in this direction.
The sea of pathological dross that must form the overwhelming but
fragmented majority of the "conscious potential" of UD* must somehow
be effectively suppressed from the perspective of the relatively
tiny, but mightily persistent and powerful narrative threads of
veridical consciousness (i.e. those that refer truthfully to an
externality that in turn explicates their perceptions of it, or what
we call physics). A pathway of least effort through the phase space
of possible subjectivity? Russell's solution to the possibility of
an Occam catastrophe that would sink this fragile vessel is simply
to assume that this physics is the unique requirement for its own
observation. Open problem, as Bruno would say?
Agreed. Open problem at the intersection of philosophy of mind,
computer science, mathematical logic, and ... experimental physics.
The main point is that it is an open problem, and the logic of self-
reference gives us some assurance that the arithmetical reality, seen
from the internal pints of view, will have psychological and physical
aspects, some of them being related to non computable, and non
provable, and non observable, not "feelable" ... elements.
Bruno
David
So there is no order imposed by the computational mechanism.
All computation are ordered structure, ordered by the universal
numbers which implement them. But indeed, the first person duration
is not directly ordered by this or that universal numbers, but by
all those who operate the computations which exists below my
substitution level.
Which probably involves the whole universe, from the big bang to the
eventual heat death -- else memories are not veridical.
The statistics over these conscious moments does not give rise to
any consistent physics. I say that "physics has to have an
independent existence" because the failure of the attempt to
extract physics from the UD means that the only way one can
connect these independent 'conscious moments' is if they are,
following Barbour, points in an independently existing
configurations space. Barbour calls this "Platonia", within which
physics is defined, but this is far from the platonia of
arithmetical realism. The upshot is that physics does not come
from the UD, but from somewhere else -- that elsewhere not
necessarily clearly specified at this point.
Since the reversal, or the extraction of physics, seems to me to
be the weak point of Bruno's argument,
Well, the goal of the UDA is just to transform the mind-body
problem into a body problem in arithmetic.
Then what is weak in the AUDA, the math part, is that nobody seems
to be interested in solving the open problems, but that is
contingent. I am not sure you can say that it is weak. It is only
unfinished, but the complexity comes from the difficulty of the
subject, which is naturally reflected in the open problems? To find
quantum logic where it is needed is on the contrary a good sign
that we might extract the full measure, then works à-la-Hardy or
Russell's, can be used to progress.
it is right that we should spend more time looking at alternative
interpretations of the UDA.
UDA is a argument, as such it does not admit any interpretation. It
is valid, or non valid. I guess you mean to search an alternative
to mechanism.
Not really at this stage -- just an alternative understanding of the
dovetailer.
Bruce
This, I would understand if the material hypostases would have
collapsed into classical logic, or would be strongly opposed to
quantum logic, but without evidence for non mechanism, I am not
sure if it is not premature to abandon mechanism , given that
mechanism already give a quantum logic. To abandon computationalism
at this stage, before testing the logic of the observable that we
already have, seems weird to me.
Bruno
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