Re: Searle: Is the Brain a Digital Computer?

From: Bon Mo (
Date: Thu Mar 08 2001 - 10:39:18 GMT

Searle: Is the Brain a Digital Computer?

> Salcedo:
> A thought is itself a conscious process, because its part of
> reasoning or is it unconscious because it happens naturally? No-one
> ever pre-defines what thought he/she is going to have. If doing it,
> they would be processing a thought as well. What matters here is
> which of these can be algorithmically defined. If assuming that both
> could be described as an algorithm, they would then be computational
> and thus we could simulate them on a digital computer.

A thought has to be part of a conscious process, it may not be pre-defined,
but instead it is selected as it has relevance to the processes at hand.
Say you were walking down the street and you see someone familiar, you
first try to associate the face to a name, but then you may try to think
of something you know about that person. These thoughts are from your
associative memory banks. These calls are often from long term memory.
Most thoughts are from routines that you have performed many times.
The unconscious thought process may actually be a layer behind the
conscious level. It could be more abstract and recall more random memory
sources, this is why people believe that they are not really thinking, as
these thoughts have no relevance to what they are doing.
Assuming that consciousness exists, there is still a large barrier for
saying that these thoughts can be described algorithmically. We do not
know how the brain works explicitly at present and we so cannot assume that
these thoughts can be written as a set of rules and facts, that can be
carried out using a UTM.

> Salcedo:
> Can we actually generalise the human brain to one human brain as we can
> with a mechanical computer? If we took several mechanical computers
> that were found to have the same internal processes as the human brain,
> would we then get different results from the mechanical computers as we
> would if checking what different people would think or do in the same
> situation/input?

As there are billions of humans, all with unique upbringings, education
and social interactions. You can see that human beings are very
individualised. Each problem we come across we use our previous knowledge
to find a optimal solution, the way we can solve a single problem may be
varied. There may literally be billions of ways a human brain can be
modeled. So how could they be generalised to such an abstract level that
more one brain may work the same? The main worry is that with such
abstraction there may be over generalisation which removes functionality.
What functions would need to be generalised from the human brain? and
how would they interact to give any reasonable representation to how
the human brain works?

> Salcedo:
> A person tends to react in the same way that is defined by its
> personality. But what exactly is personality? There is no way to physically
> describe it and, as such, to explain the events that are processed in the
> brain.
Is personality as unique as the individual human brain? Is how you react to
an event based entirely on previous circumstances? and if it is can a
personality trait be modeled to any arbitrary closeness?

> Salcedo:
> When considering the brain, who is the homunculus? Its obviously the
> owner of the brain. If we now consider a brain without a homunculus
> what would it be? How can it still compute? Would it compute? The thing
> is that physically we cannot envision a brain working without a person,
> or even, a person being alive without a human brain. But we do not know
> what happens if the brain is considered a separate entity.

Most of the brain is just sensory material connected to external sensory
devices. If these devices were removed the brain would be starved of
external stimulus. The functionality of these sections of the brain may
degrade over time. The problem with would we be able to compute, could
be based on if we have already grounded certain meanings. Say an able
bodied person lost one of their sensors i.e. sight. Now the way I see it
is that if when you had sight and knew what a tree looked like, when you
have lost your sight you can still recall images based on the reference
of a tree. For someone that has been blind all there life they would
never know what a tree looks like, but could still form an approximation
to what people describe a tree to look like. I believe that you could
still use the brain to recall what you have learnt, but if you never
knew it, then you could only approximate.
The other scenario is a human without a brain. There has been cases in the
past of babies born without a brain. Medically there are declared brain dead,
but they still live, their other organs still work and so there body can
function. All their bodies do is to react to stimulus without the intervention
of the brain. They cannot function at a social level and live out their short
lives in medical care. Basically a human body cannot function with any
intelligence without a brain.
So the brain must be the organ that gives us intelligence.

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