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machine brains

Ray Scanlon rscanlon at wsg.net
Thu Feb 4 09:29:58 EST 1999


Joe Kilner wrote in message <795ilf$9uo$1 at pegasus.csx.cam.ac.uk>...
>
>Ray Scanlon wrote in message <36b5cfd6.0 at ns2.wsg.net>...
>>
>>
>>Joe Kilner wrote in message <78q0rp$5on$1 at pegasus.csx.cam.ac.uk>...

>>>
>>>the question I am trying to get to here is that even if we were given a
>>>book
>>>consisting of a complete scientific breakdown of the brain and all the
>>>processes that occur within it, what makes you believe that that would
>>>allow
>>>us to understand *fully* our own *innate* experience of conciousness?
>>
>>
>>This is your question, not mine. I have said many times, in many places,
>>that the major impediment to any attempt to understand the brain as a meat
>>machine is this red herring of awareness (consciousness). The soul (mind)
>>and its "innate experience of consciousness" is best left to religion. We
>>use our awareness as a guide to what is an acceptable explanation of the
>>brain and that is an end to it.
>>
>>Our awareness leads us to believe that thinking is a recognizable function
>>of the mammalian brain so it interests us that the reticular nucleus of
>>the
>>thalamus is positioned to delay motor output and halt incoming signal
>>energy. This function allows extra synaptic events to be interpolated
>>between sensory input and motor output and that is what I argue is
>>thinking.
>
>Right.  What I wan't to know is "Is what you have just described the
>process
>that occurs when I see a rude double entendre in someones sentence?"  If
>you
>say that it _is_ then I would like to know how you know this, if you don't
>think that you can justify this claim then I would like to know where my
>kind of thinking "comes from".


Firstly, we eschew anthropocentrism. All vertebrate brains have the same
architecture, all mammalian brains the same floor plan. The human brain
differs from most in the number of neurons in the neocortex. Is this a
fundamental difference? Of course not, it only indicates that the human
brain may react to finer differences in sensory input. Man reacts to a
double entendre while dog does not. Dog hears the words, he lacks the number
of neurons to produce a different motor output. This is a difference in
degree, not in kind.

When we have the machinery of the mammalian brain firmly in hand and
understand how audio input is differentiated in the various nuclei leading
to the medial geniculate body and then to Brodman's  areas 41 and 42 and how
this differentiation is continued in the association areas, it will be time
to speak of a double entendre.

Secondly, we determine to do without the homunculus, the little man who sits
in the middle of the brain, watching a TV set, and punching buttons. We will
also do without his more sophisticated brother, the soul (mind), that
selects from data proffered by the brain, manipulates this data, arrives at
a conclusion, and forwards the decision to the brain for execution.

There is a neuron, there are neurons afferent upon it, and it is efferent to
other neurons. How these neurons filter incoming signal energy and how they
form a motor program that proceeds to the motor neurons is our interest. In
particular, in the mammal, there is the reticular nucleus of the thalamus
that is periodically active in halting incoming signal energy and/or
outgoing motor programs.

This activity of the reticular nucleus is crucial in understanding why the
brain activity of mammals is different from other animals. The reticular
nucleus is no pineal gland to be activated by the soul (mind), it is
activated by neurons in the other nuclei of the thalamus and by neurons in
the neocortex. This activation makes up part of our explanation of how the
brain works.

>First off then let me make sure I understand your position correctly:  You
>believe that we can get a full model of human behaviour and action from a
>scientific study of the brain.  You believe that such a study will _not_ be
>able to answer the fundamental questions of awareness because these
>questions require knowledge of the "soul" which neuroscience has not got
>access to.  You believe that the brain as a machine is simply the action of
>the sum of it's parts.

Yes.

>OK then, let me try phrasing my argument slightly differently - why do you
>believe that the brain functions independantly of our awareness of it.  And
>if it _does_ then how can we be having this discussion??  Surely the brain
>is the part of me that controlls my typing - so how does it know that there
>is something that is aware of it if it (the brain) is not able to interact
>with it (the soul)?"

To this we have no answer. The soul (mind) is aware of certain active
neurons in the brain. We do not know how it is aware. Can it be aware of
something other than an active neuron? We have no reason to say yes or no
but we can say that it is irrelevant to brain explanation.

There are three major elements in brain explanation:

 One, the neural constellations that cause the brain to function. These
constellations are the source of the drives that activate the organism.
These centers are in the brain stem, we know them as hunger, thirst, sexual
desire, and fear of the open.

Two, those molecular actions in the neurons that cause the exterior universe
to alter the effective circuitry of the brain, to strengthen synapses and
cause new axonal growth. Of especial interest in the mechanism that changes
the synapses that cause the neurons of the reticular nucleus to be
activated. We call this learning.

Three, the activation and inhibition of the neurons in the reticular nucleus
that allow extra synaptic events to be interpolated between sensory input
and motor output. We call this thinking.

>Basically I feel that the brain 's "physical" attributes are a lot simpler
>than the attributes it posseses due to it's complexity as an interconnected
>network and so for a full explanation of the brain as a machine we need to
>understand it as a netwrok and my _belief_ is that through that
>understanding we will approach an understanding of mind.  And as we have
>difficulty understanding NT networks at the moment I think the day that we
>understand the brain is quite a long way off yet (note: we may be able to
>manipulate and create brains long before we truly understand them.......)


This is holism and is intensely interesting but it belongs to religion, not
to science.

Ray
Those interested in how the brain works might look at
www.wsg.net/~rscanlon/brain.html





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