Toward a Science of Consciousness 1998

modlin at concentric.net modlin at concentric.net
Fri Apr 24 12:22:11 EST 1998


In <6hqde2$pki at ux.cs.niu.edu>, rickert at cs.niu.edu (Neil Rickert) writes:
>modlin at concentric.net writes:
>
>>But if you really mean to say that the architecture used for the
>>computing itself makes a difference to what can be computed, given the
>>necessary input and ignoring performance...  then I respectfully suggest
>>that's incorrect.
>
>The important points that you are missing are:
>
>	We are not given the necessary output.  We have to fetch our
>	own input, and make our own decisions as to what input to
>	use.
>
>	We have to make do with whatever performance we have.  It it
>	took a year to make the decision whether to eat that morsel
>	of food, we should soon starve to death.

I'm not missing those points.  I'm explicitly talking about computation,
to which they are irrelevant.  They may have a lot to do with whether a
computation is useful or effective, and we need to consider them in
talking about what is needed for consciousness and intelligence...  but
they have NOTHING at all to do with whether different architectures can
compute different functions.

Computation is transforming data according to some functional 
relationship.  What we call a computing architecture is a set of 
primitive functions plus some means of combining them to make up other 
functions not defined as primitives in the architecture.  It turns out 
that any of many very simple sets of primitives is enough to allow 
combinations implementing any other computable function.  We call an 
architecture capable of at least such a set of primitives "Turing 
complete", and any such machine can compute any function any other such 
machine can compute,  given enough resources.   This is analogous to the
notion of a "Boolean complete" set of primitive boolean operators such 
as (AND OR NOT) or (NAND).  Given a boolean-complete set of boolean 
operators you can generate all possible boolean functions, and given a 
Turing-complete set of computing primitives, you can compute all 
possible computable functions.

I'm finding it frustrating that you keep posting that you disagree, when
I know that you understand this point because you've made it clearly
yourself, several times.  Why disagree when I say the same thing?

Bill Modlin




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