On 8/18/2011 8:26 AM, Stephen P. King wrote:
On 8/18/2011 10:31 AM, Bruno Marchal wrote:
Hi Stephen,
On 17 Aug 2011, at 16:08, Stephen P. King wrote:
Hi,
Recently a link was referenced that discussed how serial
sectioning of brains is being automated:
http://www.mcb.harvard.edu/lichtman/ATLUM/ATLUM_web.htm I have a
question about this. Will this technology yield a model of the
dynamics of brain activity or will it be another taxonomy of brain
structures? It seems that dynamics are completely missing from the
narrative about scanning and uploading our brains into Turing
Machines. How exactly is a topological map of the structure of the
brain contain any information about the specifics of brain activity?
At best it might allow us to toss out models of dynamics that
have implications that would contradict the topology structure, but
nothing at all about how the topologies evolve.
I don't find the references now, but I remember having read that some
animal, like frogs, can freeze and resume the brain activity after
that. Some experience on rat shows that long term memory is preserved
in freezing, and that during freezing the activity of the brain is
really near zero. Short term memory is not. A cryogenized person
might survive with an amnesia of the last 5-6 minutes.
The dynamic of the brain is coded in the neurotransmitter
concentrations, not in the ionic potential along the axions. That
might be an argument for saying that the comp subst. level *might* be
high.
Bruno
http://iridia.ulb.ac.be/~marchal/
Hi Bruno,
Freezing would not always destroy the potentials that generate the
dynamics, thus momentum information is preserved. The microtome is
measuring pure positions of the neurotransmiters, etc. Even if we have
a precise map of all the molecules, that information is conjugate to
the momentum information. To copy a mind we need both, thus the
conjugacy makes faithfull copying and uploading impossible. There is
an inherent upper bound on the resolution of the scan thus
indeterminacy and therefore, as you argue, we only bet that the copy
has 1p continuity (bijective isomorphism or faithful homeomorphism)
with the original. I believe that this is a key feature of your result.
Onward!
Stephen
But this is exactly the point Tegmark addresses in his paper. The
temperature of the brain is such that the thermal induced uncertainity
of orders of magnitude above the QM limit. So faithful copying at the
quantum limit cannot be relevant.
Brent
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