[ExI] The digital nature of brains (was: digital simulations)

[Stathis Papaioannou]

On 30 January 2010 14:54, Eric Messick <eric at m056832107.syzygy.com> wrote:
> Gordon writes:
>>If you have a genuine interest in this subject and want to engage me
>>in intelligent discussion then please carefully read the target
>>article:
>>
>>MINDS, BRAINS, AND PROGRAMS
>>http://www.bbsonline.org/documents/a/00/00/04/84/bbs00000484-00/bbs.searle2.html

>     But the whole point of the examples has been to try to show that
>     that couldn't be sufficient for understanding, in the sense in
>     which I understand stories in English, because a person, and
>     hence the set of systems that go to make up a person, could have
>     the right combination of input, output, and program and still not
>     understand anything in the relevant literal sense in which I
>     understand English.
>
> Level of abstraction error again: because the human does not
> understand, the vastly greater system which it is a part of must not
> understand either.
>
>     In short, the systems reply simply begs the question by insisting
>     without argument that the system must understand Chinese.
>
> Looks to me like Searle is projecting a bit of begging the question
> onto his criticizers.  Searle states as part of the problem that the
> system behaves as though it understands Chinese as well as a native
> speaker.  He then repeatedly assumes that the system does not
> understand, and concludes that it does not understand.
>
> The systems critique can be stated without an assumption of
> understanding:
>
>  If there is understanding, then it can reside outside of the human
>  component.
>
> Which is still enough to devastate most of Searle's claims, as he's
> always relying on his statement that the human doesn't understand to
> support the notion that there is no understanding.

This seems to be the main problem with the Chinese Room Argument.
Searle assumes that because the human doesn't understand Chinese, the
Chinese Room doesn't understand Chinese. He counters the systems
critique by modifying the experiment so that the man internalises the
symbol manipulation protocols, i.e. so that the man is now the whole
system. But that just indicates that he doesn't understand the systems
critique.

>     Of course the brain is a digital computer. Since everything is a
>     digital computer, brains are too.
>
> What?!  Everything is a digital computer?  That's just absurd.  I have
> no clue what he's trying to say here.  He's not attributing this to
> someone he's criticizing, though.  I see nothing to suggest that it
> isn't a serious statement.  I can't attach a coherent meaning to that
> string of symbols, though.

I think he means that the brain, like everything else, is computable,
a statement of the physical Church-Turing thesis:

"If by "digital computer" we mean anything at all that has a level of
description where it can correctly be described as the instantiation
of a computer program, then again the answer is, of course, yes, since
we are the instantiations of any number of computer programs, and we
can think."



-- 
Stathis Papaioannou