machine brains

Malcolm McMahon malcolm at pigsty.demon.co.uk
Wed Mar 10 17:00:49 EST 1999


On Tue, 09 Mar 1999 10:19:54 -0500, Michael Edelman <mje at mich.com>
wrote:

>
>
>Malcolm McMahon wrote:
>
>> ...
>> >
>> >That would be very energy inefficient. Neurons don't grow at random. There needs to be some sort
>> >of activity or chemical trigger.
>> >
>>
>> It may be the only way to go. It is known that most young neurons which
>> are produced during the growth of an embryo self-destruct.
>
>Not self-destruct, but atrophy from disuse.

Exactly the same thing. There's a word I'm looking for Aposteousis?
Something like that when a body cell decides it's not wanted and
dismantles itself. There's a lot of recent research on this and it seems
to be a very important aspect of morphogenesis.

> You start out with a surplus of synapses and select. But
>that's different from unregulated growth.
>

Is it? The surplus appears in the first place by relaxing regulation of
growth. It looks like a trial and error process.

>> ... The material from
>> cells that suicide is available for other cells.
>
>Mm. No. Generating and supporting cells is energy intensive. It requires energy to clean up dead
>cells. The remains are excreted.
>

I seem to recall part of the recent work on programmed cell death shows
that these cells don't just die, they dismantle themselves to make their
material available.

>>
>> Yup, but the effect is the same in that either will disrupt any volatile
>> data in the system which will have to start with only non-volatile data.
>
>You may be inferring too much from the computer metaphor. ECT disrupts LTM. The older the memory the
>more resistant to loss, but that's probably a function of how integrated it is, not whether it's
>electrical in nature.
>

But short term memory is completely wiped. I suspect the effects on LTM
are just an aspect of the general brain damage which is a side effect of
the process.

>> I'd speculate that certain pathological mental conditions might be the
>> equivalent of a computer being stuck in a loop, or blocked by some kind
>> of mutual lockout.
>
>Again, I think you're delving into the realm of the metaphorical. There are psychopathologies that
>can be described as self-reinforcing but that's feedback on a much more abstract level.
>

So how do you explain the benefits of ECT?

>> >> I certainly don't dismiss its existance, only that it can be observed
>> >> other than subjectively.
>> >
>> > So the quesiton is whether we can do science on conciousness. I think we can.
>>
>> We may be able to look at the interface between consciousness and the
>> rest of the universe and learn a lot about how consciousness behaves.
>> This doesn't necessarilly tell us anything about what consciousness is,
>> though it might prove very usefull.
>
>We can't examine QSOs or quarks, yet we can make reasonable deductions about their composition and
>physics. So it is with conciousness.
>

We can make deductions about their physics, the way they interact with
other parciles but we learn nothing about their composition, in fact
they probably _have_ no composition.


>> >> Rather, what it does is to deal with those that say that nothing
>> >> constructed of known particles can exist.
>> >
>> >Are you taking a sort of vitalist stance here- that conciousness is a non-physical
>> >substance? I'm not entirely clear as to your argument on this point.
>>
>> What I'm saying is that something can be physical, and real without
>> being composed of material known to physics. This is, I guess, a
>> vitalist position in some ways (though there's no proof that all life is
>> conscious or that all consciousness exists in living things).
>
>Once you say "physical" you're saying it has some sort of physical extension, which certainly puts
>you in the vitalist camp. Why do you think this is the case?

Because I don't think that mental process provides the kind of
explanation needed for consciousness as we experience it.

>
>> >> > And anyways,
>> >> >conciousness is far too complex to compare it to an electron ;-)
>> >>
>> >> Now that's an interesting aspect. If you separate consciousness from
>> >> mind, and ego then why does it need to be complex?
>
>I don't. Conciousness is a property of mind.
>

But an explanation of the sort I favour doesn't have that requirement so
complexity is not an objection to my argument.

>> >
>> >Re my earlier argument, which relies on a definition of complexity: How much
>> >information does it take to describe? The amount of information needed to describe a
>> >unique conciousness is far greater than that needed to describe a unique electron.
>> >
>>
>> Not necessarilly because the detail you're talking about is the detail
>> fo the ego, not of the conscious self.
>
> My conception is that eg  is an aspect of concious self.

It's a matter of defining boundaries, I think.




More information about the Bioforum mailing list