On 8/05/2017 3:14 am, David Nyman wrote:
On 6 May 2017 11:04 p.m., "Brent Meeker" <[email protected]> wrote:
On 5/6/2017 2:45 PM, David Nyman wrote:
On 6 May 2017 10:16 p.m., "Brent Meeker" <[email protected]
<mailto:[email protected]>> wrote:
But that's what I mean when I say Bruno's theory has no
predictive success. QM (and Everett) would correctly predict
that alcohol molecules in the blood will interfere with
neuronal function and THEN invoking the physicalist theory of
mind, i.e. that mind supervenes on material events, it
predicts that your ability to do arithmetic will be impaired
by drinking tequila. It will NOT predict the contrary with
more than infinitesimal probability. So it's misdirection to
say that it's just a measure problem. Without having the
right measure a probabilistic theory is just fantasy...or
magic as Bruno would say.
I have no idea why you say that. I thought it was clear that if
computationalism doesn't (ultimately) predict that its
predominating computational mechanism (i.e. the one effectively
self-selected by complex subjects, in this case, like ourselves)
is the physics those selfsame subjects observe,
That would certainly be an accomplishment - which in another post
Bruno says is trivially accomplished even in RA (I don't see it).
But to succeed in prediction it is not enough to show that some
world exists in which mind and physics are consistent (that the
physics that mind infers is also the real physics that predicts
effects on the mind). You need also to show this has large
measure relative to contrary worlds. One can make a logic chopping
argument that it must be that way for otherwise minds would not be
making sense of the physics they perceived - but that makes the
whole computational argument otiose.
I've been thinking a bit more about this and I'd like to set out some
further tentative remarks about the above. Your professional expertise
in these matters is orders of magnitude greater than mine and
consequently any comments you might make would be very helpful. By the
way, it would also be helpful if you would read beyond the next
paragraph before commenting because I hope I will come by myself to
the fly in the ointment.
Firstly, and "assuming computationalism" on the basis of CT + YD, we
are led to the view that UD* must include all possible "physical"
computational continuations (actually infinitely reiterated). This of
course is also to assume that all such continuations are finitely
computable (i.e. halting). Now, again on the same assumptions, it
might seem reasonable that our observing such a physics in concrete
substantial form is evidence of its emergence (i.e. epistemologically)
as the predominant computational mechanism underlying those very
perceptions. Hence it might seem equally reasonable to conclude that
this is the reason that these latter correspondingly appear to
supervene on concrete physical manifestations in their effective
environment.
Now wait a minute. We cannot escape the question of measure. Why would
it be reasonable to assume that a physics of this sort should
predominate in the manner outlined above? Well, firstly, it would seem
that the generator of the set of possible physical computations is
infinitely reiterative​ and hence very robust (both in the sense of
computational inclusiveness a la step 7, and that of internal
self-consistency). But who is to say that the generators of "magical"
or simply inconsistent continuations aren't equally or even more
prevalent? After all we're dealing with a Library of Babel here and
the Vast majority of any such library is bound to be gibberish. Well,
I'm wondering​ about an analogy with Feynman's path integral idea
(comments particularly appreciated here). Might a kind of least action
principle be applicable here, such that internally consistent
computations self-reinforce, whereas inconsistent ones in effect
self-cancel?
Also, absence of evidence isn't evidence of absence. I'm thinking here
about the evaluation of what we typically remember having experienced.
I can't help invoking Hoyle here again (sorry). Subjectively speaking,
there's a kind of struggle always in process between remembering and
forgetting. So on the basis suggested above, and from the abstract
point of view of Hoyle's singular agent (or equally Bruno's virgin
machine), inconsistent paths might plausibly tend to result, in
effect, in a net (unintelligible) forgetting and contrariwise,
self-consistent paths might equally plausibly result in a net
(intelligible) remembering. I'm speaking of consistent and hence
intelligible "personal histories" here. But perhaps you would
substitute "implausibly" above. Anyway, your comments as ever
particularly appreciated.
I think the problem here is the use of the word "consistent". You refer
to "internally consistent computations" and "consistent and hence
intelligible 'personal histories'." But what is the measure of such
consistency? You cannot use the idea of 'consistent according to some
physical laws', because it is those laws that you are supposedly
deriving -- they cannot form part of the derivation. I don't think any
notion of logical consistency can fill the bill here. It is logically
consistent that my present conscious moment, with its rich record of
memories of a physical world, stretching back to childhood, is all an
illusion of the momentary point in a computational history: the
continuation of this computation back into the past, and forward into
the future, could be just white noise! That is not logically
inconsistent, or comutationally inconsistent. It is inconsistent only
with the physical laws of conservation and persistence. But at this
point, you do not have such laws!
In fact, just as Boltzmann realized in the Boltzmann brain problem,
states of complete randomness both before and after our current
conscious moment are overwhelmingly more likley than that our present
moment is immersed in a physics that involves exceptionless conservation
laws, so that the past and future can both be evolved from our present
state by the application of persistent and pervasive physical laws.
Unless you can give some meaning to the concept of "consistent" that
does not just beg the question, then I think Boltzmann's problem will
destroy your search for some 'measure' that makes our experience of
physical laws (any physical laws, not just those we actually observe)
overwhelmingly likely.
Bruce
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