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machine brains

Michael Edelman mje at mich.com
Wed Feb 24 08:44:41 EST 1999



Ray Scanlon wrote:

> e... My interest is in the nervous system
> as it is seen objectively by the neuroscientist. I see no "if" neurons and
> no "then" neurons. Cognition is the activity of the brain as seen
> subjectively by the soul (mind).

You maintain that the mind- which he terms synonymous with soul- is the purview
of theology. And yet you seem to accept its existence. Further:

> Many people believe that the objective and
> subjective views of brain activity may be blended "scientifically". I do
> not. I hold that the subjective view of brain activity belongs to religion.

This view doesn't seem self-consistant.

> This is in no way derogatory of religion. I merely believe that science and
> religion are separate and must remain so. Science is the objective
> examination of the material universe, religion is the subjective view of the
> spiritual universe. I enter both but I keep them separate.

Suddenly mind is "spiritual". I don't think you have a very good argument for
this. The metaphysical is the world that cannot be observed, tested or accessed,
and cannot be shared. Yet the mental world has all these properties. I can
decribe all my subjective experiences to you, and you can understand them in the
same way that you understand the description of physical experience. Each of us
understands what it means for another to have a mental life. We can even
communicate the contents of this mental life with a language based on shared
experience.

What's the difference between me telling you that the air feels cold and me
telling you that I am imagining that the air feels cold? Both are understood by
you in terms of our shared experience of both our physical and our mental life.
And someone has to do the telling. Suppose I say I'm thinking of a pink elephant
with wings? Neither of us has ever seen a pink elephant with wings- and yet we
are both able to share the mental experience of imagining such a beast.

> When speaking of the objective view of the nervous system, I believe that
> the neurons functions without any input from soul (mind). This is usually
> called epiphenomenalism, a good a name as any.

That term was used by the behaviorists to describe mind as *unimportant* to the
function of body. They wanted to reduce all human activity to behavior, i.e.,
conditioned response to stimuli.  It suggests that mind is a byproduct of brain
function that plays no role in it. This has always struck me as a view that
requires one to make some very large leaps of belief, most notably that our
common everyday experience is a mere phantasm. Yet even if a phantasm it has to
be experienced by some entity.

And it's certainly clear that the mind has tremendous influence over the
physical body. I can, by concentrating, slow down or speed up my heart rate. For
that matter, I can simply decide to raise my arm. Or I can decide to write this
missive. The decision may be mapped in terms of electrophysiology, but to say
that I type a letter because a neuron fires is no more meaningful than to say
that a light bulb goes on because a stream of electrons courses through it. Such
a description is necessary but not sufficient.

> >If so you would agree that whatever it is that allows cognitive function is
> >inherent within the brain’s material structure.  Yes?
>
> No. Cognition involves awareness and judgement. Consciousness has two
> aspects: One, objective, we call alertness; the other, subjective, we call
> awareness.
>

I have a problem with this as well. You seem to have a private terminology.
There is no "we". To a psychologist, to be alert is to attend to and be aware
of  external stimuli- but that implies someone is doing the attending. We always
process external stimuli- but at what level? In a relaxed state, the highest
level of conciousness is not attending to most external stilumi. Only something
above a certain limen will make it through lower levels and up to concious
awareness. As the level of alertness increases, increased amounts of concious
processing are assigned to attend those stimli. And all this is inder the
concious control of the person.

> I am aware.
> You are alert.
> He exhibits intelligent behavior.
>
> Cognition is subjective and belongs to religion. What we find in the brain
> are interacting neurons. These neurons serve as a filter for signal energy
> on its way from sensory neurons to motor neurons.

What we find in the body are proteins. Yet the body is more than a mass of
proteins. You can't build a person out of filters. There's feedback, and there
is a level of complexity of organization above which properties emerge that are
not strictly predictable from the observed lower-level processes. At this level
there is spontaneous as well as controlled reorganization of structure. There
emerges an entity that can operate on itself.

> >Why then, is it assumed that whatever it is that allows self awareness is
> >NOT
> >inherent within the brain’s material structure?
>
> This is what I deplore, the desire, when speaking of brain action, to start
> from the top rather than the bottom. Consider: when food is placed in the
> mouth, mastication and swallowing follow. These physical activities are
> driven by neurons in the brain stem. This is the brain in action.

You cannot predict all the higher-level properties of the brain by looking only
at the neurons. Certainly bottom-up is a good place to start, but you begin by
defining the problem down to one so simple it's hardly worth investigating.

If you began by assuming that mind was a real construct, it wouldn't limit your
research program, or change the way you do it. Quite the opposite- it would give
you access to more data, and further extend its range. If at some point you stop
and say ah, I've explained all human action without invoking conciousness, then
you've established your case. But if you start by simply assuming away what most
people would consider critical aspects of the human brain, then you've simply
assigned yourself a limited program.

> As we move up to the next step, the search for food, we ask, "How did the
> DNA wire the brain so that it will drive the organism to 'bring food to the
> mouth'?" This process is essentially the same in fish and man. We add layers
> of complication, that is all.

Why? You assert that there are no higher-order constructs like mind. So what's
the point of increased complexity? If it's only additive, why don't
200,00,000,000 paramecium write a book- or post to the net?

> This complication of brain action leads finally in the mammal to the
> interpolation of an indefinite number of synaptic events being interpolated
> between sensory input and motor output. Subjectively we are aware of this as
> "thinking".

This is the point at which I find myself shaking my head. Who is aware of
thinking? When you say "subjectively" you imply a subject. Who is that subject?

You have not argued for the non-existence of mind or self-awareness. You merely
assert that it does not exist.

-- mike




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