Johnathan Corgan wrote:
On Fri, Jan 8, 2010 at 10:03 AM, Brent Meeker <[email protected]> wrote:
Isn't it? Bruno presents "comp" as equivalent to betting that replacing
your brain with a digitial device at the appropriate level of substitution
will leave your stream of consciousness unaffected. From this people are
inferring that the discrete states of this digital brain instantiate
"observer moments". But suppose (which I consider likely) the digital brain
would have to have a cycle time of a billionth of a second or less. I don't
think you believe you have a different conscious thought every billionth of
a second. What it means is that "a state of your consciousness" corresponds
to a million or so successive states of the digitial computation. These
sets of a million states can then of course overlap. So the idea of
discrete "observer moments" doesn't follow from "yes doctor".
It's plausible that "observer moments" correspond to what are called
"chaotic attractors" in complex systems theory.
The brain passes through a complex, dynamic trajectory of states. A
stable attractor is a cycle of discrete states that repeats exactly,
in the case of a "limit cycle", or more often, retraces a similar but
not exact trajectory, in the case of a "chaotic attractor". Chaotic
attractors are robust to perturbation, up to a point, and many complex
systems can be characterized by a succession of chaotic attractors
separated by rapid transitions driven by external perturbations
exceeding some threshold. I use the term "meta-state" as a synonym
for chaotic attractor in this context.
My working hypothesis is that nervous systems developed into complex
systems capable of generating quasi-stable meta-states which were
evolutionarily advantageous, and over (evolutionary) time, were able
to reach a level of organization which eventually produced
consciousness.
In this model, brains are continuously cycling through patterns of
firing, which, absent external stimuli, are self-sustaining in some
sort quasi-stable chaotic fashion, or meta-state. Sensory input of
various types may be "ignored" if it doesn't reach a threshold of
activation which tips the brain into a new meta-state. Or, "novel"
sensations may drive the system into a new meta-state (dynamic cycle)
that corresponds to some classification of that input in the context
of whatever the current meta-state is.
Observer moments, then, correspond to some subset of meta-states in
the brain. They aren't discrete states of zero duration, but
trajectories of states in a chaotic cycle. A succession of these
meta-states would then make up a stream-of-consciousness.
As an aside, I strongly suspect that in practice, our sensory input
serves to constrain the brain into a (relatively) small set of
meta-states that has allowed us to survive in a harsh evolutionary
context, and produces what may be called "consensus reality" (I think
Bruno calls this 1st-person plural.) Other chaotic systems do spend
most of their time in a small subset of possible states. Yet there is
evidence that perturbing the brain in a variety of ways (fasting,
breathing exercises, meditation, religious contemplation, drugs,
disease, injury, etc.) can allow it to wander off into meta-states
that are quite subjectively different from the typical states
associated with "normal" functioning.
All of the above speculation could still hold true in a
non-physicalist, computationalism-based view of consciousness, where
one would replace "brain" with "computational substrate at appropriate
level of substitution."
Johnathan Corgan
That would correspond to my intuition about consciousness. I remember
reading in the '60s, when sensory deprivation experiments were the fad,
that if one remained long enough in a sensory deprivation tank (more
than about 45min) one's mind went into a loop. I've not been able to
find a reference to this, but that's what I remember.
Brent
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