machine brains

Jerry Hull ZZZghull at stny.lrun.com
Sun Mar 7 11:01:57 EST 1999


On Sun, 07 Mar 1999 11:21:39 GMT, malcolm at pigsty.demon.co.uk (Malcolm McMahon)
wrote:

>On Sun, 07 Mar 1999 05:39:13 GMT, ZZZghull at stny.lrun.com (Jerry Hull)
>wrote:

>>The notion of being "made of" has a number of different interpretations, some
>>of which clearly do NOT apply to "mental" things the way they apply to
>>material things.  In particular, there is no mental analog for the sense in
>>which water is "made of" of oxygen & hydrogen.  Mentally, there are only
>>analytic -- as contrasted with synthetic -- forms of composition, as it were.
>
>Oh, I can't agree with that. There's at least as much synthesis as
>analysis going on in the brain. Complex ideas are made of simpler ideas.
>When we examine the scene before our eyes what are we doing? We're
>recognising elements of that scene and composing a model of our
>surroundings in terms of objects we're familiar with. Exactly the same
>with hearing speach or reading a paragraph. Perhaps the "elementary
>particle" of thought is the firing of a neuron.

I'm using a technical meaning of 'analytic' and 'synthetic' that you may be
unfamiliar with.  The relation between a term and its definition is a logical,
ANALYTIC relation; the relation between a cause and its effect is NOT ANALYTIC
(fundamentally, for reasons detailed by Hume), but empirical, contingent,
SYNTHETIC.

The only sense in which one thought can be "composed" of another thought, is
to find that other thought hidden in it.  This kind of composition was
distinguished by Kant as "analytic", as opposed to "synthetic".

>>What's wrong is wrong always, even tho people at some particular time may be
>>confused or mistaken.
>
>Let's not be too arrogant. Descartes had a model which fitted the facts
>he was aware of, we have models which also fit facts he wasn't aware of.
>50 years from now you can count on their being more facts.

Who's being arrogant?  Descartes was right about some things and wrong about
others.  He was the first to be wrong about certain things, a real
philosophical achievement, I say with no touch of irony.  We today are
probably wrong about some of the things we take to be true.  So what?

You cannot even STATE your temporal relativism without contradicting yourself
-- i.e., you have to take a NON-temporally relative perspective to state
"truths are temporally relative".

>>Consciousness pretty much DEFINES what 'mental' is customarily taken to mean.
>>That is why it is so perverse to suggest that the two should be separate.
>
>No, I don't agree that mental processing is either necessary or
>sufficient for consciousness to be present. A computer vision system or
>an expert system, I would argue, perform functions we would characterise
>as mental if an animal was doing them, yet we don't imagine that such
>systems have consciousness.

You are fighting with your own idiosyncracies of language.  I know of noone
who regards "mental" as the name of a certain kind of processing, as OPPOSED
to consciousness.  Since you are using words in a peculiar way, it's hard to
know exactly what you believe.  I AGREE that there can be isomorphisms between
what a computer algorithm is doing and what the brain is doing, when it e.g.
processes vision.  But such algorithms are certainly not part of the MEANING
of 'mental' or 'vision' for me and I suspect most speakers of the English
language.  You are using the word 'mental' to describe things that are
conventionally understood to be 'PHYSICAL', i.e., what is going on in the
brain, &c.

>Because thought is what we (and especially philosohpers) think we excell
>at we tend to exagerate it's significance. We'd like to believe that
>consciousness in things exists in direct proportion to their
>ressemblence to us.

Who believes that?  & if so, so what?

>>>But a particular mind dictates (or is instanciated) as more than the
>>>electrical state of the brain. It's written into the actual
>>>microsturture. To make a new instance of a mind you'd have to actually
>>>physically duplicate, or fully model the physical brain (or at least
>>>crucial parts of it).
>>
>>When you find out how this is done, please let the rest of us know.
>
>Oh, it's easy enough to see how it might be done in principle. It's just
>beyond our present technology. I'd give it 50-100 yeare.
>
>You'd inject vast numbers of nano-machines into the CS fluid. These
>nanites would spread throughout the CNS, following and tagging neural
>processes, examining the state of pre-synaptic membranes in order to
>measure the "gain" on the different synapses. Each nanomachine would
>record a few neurons in detail together with information about other
>nano-machines and their tags encountered. When they'd been in for long
>enough you'd "lure" them out of the body with some kind of marker
>chemical. Between them they'd cary an almost complete picture of the
>engram.

You assume you know how the brain stores information; I believe this has not
yet been settled.  Certainly there must be SOMETHING in the brain, &c. that
contains ALL the information involved in any given thought, but since we have
not yet nailed that down, it's hardly simply a TECHNICAL problem.

>We already model very simple neural networks on ordinary computers or
>specialised hardware.

But we don't know how well NNs emulate real neurons, or whether they capture
ALL neural behavior relevant to consciousness.  The problem is sooo easy when
you just assume it has been solved.

--
Jer
"However far you may travel in this world, you will still occupy 
the same volume of space".  Traditional Ur-Bororo saying.



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