On 4/8/2015 4:29 PM, Bruce Kellett wrote:
Bruno Marchal wrote:
The main point is that for a physical universe to exists in some primary form, you have
to abandon the idea that a brain is Turing emulable.
Not so. You essentially admit as much in the 'yes doctor' scenario. If you are happy to
replace your physical brain with one simulated in a computer, then you are saying that
the physical brain is Turing emulable. This stands to reason if you believe that the
brain is essentially classical in its operation -- it is large and warm so quantum
effects decohere far too rapidly to have any significant large-scale effect. The
operation of this physical object is then completely classical, and determined by
physical laws that are deterministic. If you know the laws and the initial conditions,
then the future activity of that brain can be completely calculated on a computer.
The problem, of course, arises with the requirement that you know, or can determine, the
initial conditions. I suggest that this is impossible in principle. Physical limitations
are such that in any attempt to extract a complete map of the state of a living brain at
any instant, the machinery would destroy the brain *before* any such map could be
completed.
'Yes doctor' fails because the necessary starting conditions cannot be realized for
physical reasons.
This does not mean that one cannot create a physical computer that completely models the
human brain -- in other words, you could create a conscious human-like entity. But you
would necessarily always create a /different/ person in this way, not a copy of an
existing person.
And not only because of initial conditions, but also because of interaction with the
environment. This can't be negligble, because it is what makes the computations of the
brain classical (or nearly so) and besides the incidental interactions I think perception
is also necessary. Both of these will cause any replicated brain to instantly diverge
from it's original.
I am actually interested in Bruno's idea of consciousness; but I'm not clear on whether
there is anything useful in axiomatically defining knowledge in terms of provability.
What does that tell me about whether my Mars Rover is conscious or not?
Brent
But whether these means that consciousness is primarily computational or primarily
physical is just a matter of which way the rabbit jumps.
Bruce
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at http://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.
