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Article 2971 of comp.ai.philosophy:
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>From: geb@dsl.pitt.edu (gordon e. banks)
Newsgroups: comp.ai.philosophy
Subject: Re: Anesthesia
Message-ID: <13086@pitt.UUCP>
Date: 21 Jan 92 22:13:36 GMT
References: <62373@netnews.upenn.edu> <13010@pitt.UUCP> <62555@netnews.upenn.edu>
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Organization: Decision Systems Laboratory, Univ. of Pittsburgh, PA.
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In article <62555@netnews.upenn.edu> weemba@libra.wistar.upenn.edu (Matthew P Wiener) writes:
>In article <13010@pitt.UUCP>, geb@dsl (gordon e. banks) writes:
>>Incidentally, you mentioned general anesthesia as a problem for the
>>neuronal theory of consciousness.  Can you be more specific?
>
>The curious way in which consciousness alone seems to be negated.  Sensory
>input and learning and emotional reaction can still go on under anesthesia.
>A purely neural network theory of all mental features will have to show
>some extra ingenuity to explain this.
>
Well, that depends on the type of anesthesia.  In most cases, there is
no memory (and thus no learning) and patients recall nothing, making
it hard to test just what might or might not have been present.  There
are sporadic cases of people being remembering things happening during
anesthesia, but in those cases, why say that they were unconscious?
I would say if they have such recall, they are conscious.  Also, many
of these cases can be explained by the fact that if you are not
careful, anesthesia can get pretty light and the patient can wake up.
Since nowadays, patients are generally paralyzed, the patient's motor
activity is no clue to the depth of anesthesia and so other more
subtle clues have to be used to make sure the patient stays out.
Another point: various systems of the brain such as the thalamus,
which feels the pain, and the reticular activating system, which
maintains consciousness, may not have the same sorts of neurons
or neurotransmitters.  Various agents may act differentially on
them, producing loss of consciousness without loss of pain reaction,
or the converse.

>>Again, what exactly do you mean by conscious?
>
>Nothing "exact" in particular.  It's a flexible concept that none of us
>understand yet.  How else could I say "so give the dogfish ..."?

Well, before we say what types of animals are conscious and what
aren't, we'd better have a better idea of what we mean by conscious,
I'd say.  Too much fuzziness and flexibility makes it hard to say
anything sensible about it.


-- 
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Gordon Banks  N3JXP      | "I have given you an argument; I am not obliged
geb@cadre.dsl.pitt.edu   |  to supply you with an understanding." -S.Johnson
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