[ExI] Zombie glutamate

[Stathis Papaioannou]

On 18 February 2015 at 13:44, John Clark <johnkclark at gmail.com> wrote:
> On Tue, Feb 17, 2015  Stathis Papaioannou <stathisp at gmail.com> wrote:
>
>>  > my contention is that if the glutamate substitute can mimic all the
>> properties of glutamate relevant to brain function, then it will
necessarily
>> also contribute to consciousness in whatever way natural glutamate does.
>
>
> I'm just playing devil's advocate here but it could be argued that there
is
> one brain function that you have absolutely no way of knowing if the
> substitute glutamate has successfully mimicked or not, the consciousness
> function. It could be argued that the substitute glutamate works great on
> everything you can test in the lab, everything you can count or measure,
but
> the substitute doesn't work for conscious, which therefor must have been
> created by something other than Evolution.
>
> Please note that I think the above idea is very silly, but I can't prove
it
> wrong and never will be able to. And that is the very definition of a
silly
> theory. Perhaps I'm just taking the word "proof" a little too seriously,
I'm
> think of a mathematician nitpicking over every line, but if you mean
> evidence so overwhelming that it is correct life is too short to worry
about
> it being wrong then I agree with you.

If that idea is true it leads to worse than just silliness; it invalidates
the idea of consciousness.

Functions in the brain are, to an extent, localised. The visual cortex is
where perception occurs, Broca's and Wernicke's areas are where speech
understanding and production are controlled. We know this because if a part
of the brain is damaged it results in specific deficits in function, while
other functions are left unaffected. So if the visual cortex is taken out
the subject can't see, although he can speak normally, and he says, "I
can't see". This is because there are neural connections between the speech
and visual centres in the brain. The eyes register an image, signals travel
to the visual cortex, neural processing occurs there, and output is sent
from the visual cortex to other parts of the brain, including the speech
centres, where more processing occurs. The speech centres then send output
to motor neurones controlling the vocal cords and speech is produced.

Now, what happens if you replace the visual cortex with a perfect
functional analogue which, however, lacks the special "function" of
consciousness? The scientists and engineers designing this device will
replicate EVERY FUNCTION THAT CAN POSSIBLY BE SCIENTIFICALLY TESTED FOR.
They may leave out the functions that can't be tested for, of which
consciousness may be one, but they will do a good job with all the others.
The artificial device will have the same connections to the surrounding
brain tissue as the original visual cortex did, and it will accept input,
process it, and send output to other parts of the brain just as the
original visual cortex did. If there is some other way the different parts
of the brain communicate with each other that we don't know about, the
super competent designers will discover it and find a way to reproduce it.

Now I hope you can see that if EVERY FUNCTION THAT CAN POSSIBLY BE
SCIENTIFICALLY TESTED FOR is incorporated into the artificial visual cortex
then it will receive and process input and send output to the rest of the
brain in the same way as the original visual cortex; for if not, that would
be a difference in a FUNCTION THAT CAN POSSIBLY BE SCIENTIFICALLY TESTED
FOR, rather than a difference in one of the functions that can't be tested
for, like consciousness. And if the output coming from the artificial
visual cortex is completely normal, the subject will behave completely
normally; signals will go from the retina via multiple neural and
artificial relays to the vocal cords and the subject will declare that he
can see perfectly normally. However, what would happen if there is a
function that can't be scientifically tested for, responsible for visual
perception (i.e. consciousness) in the cortex? That function would be left
out and the subject would be blind; but because the artificial visual
cortex is sending all the right signals to his speech centres, and every
other part of his brain, he doesn't realise he is blind and he still
declares that he can see normally.

So do you see the problem with this? If consciousness is not a necessary
side-effect of observable processes, it would be possible to remove a major
aspect of a person's consciousness, such as visual perception, but they
would behave normally and they would not notice that anything had changed.
Which would mean that you could have gone blind an hour ago but haven't
realised it. In which case, what is the difference between being blind and
not being blind? And, extending the argument by gradually extending the
extent of the brain replacement, what is the difference between conscious
and not being conscious?



--
Stathis Papaioannou
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