Necessary conditions for consciousness
lloren at mitre.org
Thu Feb 8 10:53:45 EST 2001
> Damage to a peripheral body part will affect its conscious representation
> in the brain, but the conscious representation is in the brain. For example,
> removal of an arm will create a lack of sensory experience of the arm in the
> brain. However, a phantom limb is consciously perceived because of the
> representation in the brain.
One of the interesting questions is how the body is represented in the
brain. You said that "phantom limb is consciously perceived because of
the representation in the brain" but phantom limbs do not always occur
when a limb is amputated. If you maintain that the body is explicitly
represented in the brain (like a sort of virtual construct) then
removing a limb may or may not result in a change to that body image.
But if this is the case, then why point to a change in the brains
representation of the body. The amputation, after all, occurred to the
body not the brain. A phantom limb is not caused by a change in, or
damage to, the brain it's caused by damage to the body. If you'll permit
me to tell a story that fits the facts (as opposed to a theory confirmed
by evidence) it looks as if the body is responsible for telling the
brain that it is there, and what condition it is in. A phantom limb can
then explained as the body mistakenly reporting that the limb is still
present because the nerve endings in the affected area continue to
report that something is there. I also find this explanation more
parsimonious. There is little reason to have an explicit representation
of the body when I have an actual body. If my brain wants to know
whether or not I have a left arm, why check an internal representation
of my body when I can just check my body and see if the limb is still
reporting for duty?
> By the way, I think it's important to distinguish between two common usages
> of the term consciousness, which may ultimately be part of the same thing.
> Some use the term to refer to an aroused, awake state while others use it to
> refer to self-awareness. I guess I'm being slippery here and using it to
> refer to both.
One other point worth mentioning is that consciousness implies a
"consciousness of". If you are not conscious of something, then you are
not conscious at all. But the notion of "conscious of" implicates the
body. If we are to be conscious of something, then there must be a
sensory/perceptual system in place. Pointing out that you can be
conscious of memories, which do not appear to require sensory/perceptual
apparatus will not do since those same memories are rooted in
experiences that did involve sensation and perceptions (i.e. the body).
> > I would say that the brain stretches through the body and therefore you
> > feel things in and around your body, but that part of your brain is not
> > necessary for consciousness to occur. Just as damages in a lot of other
> > parts of your brain doesn't affect consciousness either. (I take it that
> > mean consciousness and not memories or the ability to play soccer).
> > Sorry for the rambling. What I want to say is that the brain can take a
> > of damage and still have the 'experience of consciousness', and that you
> > therefore can't say that it is the brain as a whole that is conscious, but
> > rather a part of it.
If you are willing to say that the "brain stretches through the body"
(and presumable also admit that consciousness permeates the body) then
why say "it is [not] the brain as a while that is conscious, but rather
a part of it"? Why not just say that intelligence and consciousness are
properties of the bodies. Once again, I don't mean to say that the brain
is not involved, clearly it is an extremely important organ for both
intelligence and consciousness. The problem, I think, is that people
tend to focus on the brain to the exclusion of the body, and in so doing
overlook the role of the body.
Of course that's just my opinion, and no doubt some (most?) would
disagree with me.
P.S. thoroughly enjoyable conversation!
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