DRogers@SUMEX-AIM.ARPA (10/25/83)
From: David Rogers <DRogers@SUMEX-AIM.ARPA>
I cannot say that "parallelism and consciousness are necessarily
related", for one can (at least) simulate a parallel process on a
sequential machine. However, just because one has the ability to
represent a process in a certain form does not guarantee that this
is the most natural form to represent it in; e.g., FORTRAN and LISP
are theoretically as powerful, but who wants to program an expert
system in FORTRAN?
Top-down programming of knowledge is not (in my opinion) an
easy candidate for parallelism; one can hope for large
speed-ups of execution speed, but rarely are the algorithms
able to naturally utilize the ability of parallel systems to
support interacting non-deterministic processes. (I'm sure
I'll hear from some parallel logic programmer on that one).
My candidate for developing parallelism and consciousness involves
incorporating the non-determinism at the heart of the system, by
using a large number of subcognitive processes operating in
parallel; this is essentially Hofstadter's concept of consciousness
being an epiphenomenon of the interacting structures, and not being
explicitly programmed.
The reason for the parallelism is twofold. First, I would
assume that a system of interacting subcognitive structures would
have a significant amount of "random" effort, while the more
condensed logic based system would be more computationally more
efficient. Thus, the parallelism is partially used to offset the
added cost of the more fluid, random motion of the interacting
processes.
Second, the interacting processes would allow a natural interplay
between events based on time; for example, infinite loops are
easily avoided through having a process interrupt if too much
time is taken. The blackboard architecture is also naturally
represented in parallel, as a number of coordinating processes
scribble on a shared data structure. Actually, in my mind, the
blackboard structure has not been developed fully; I have the
image of people at a party in my mind, with groups forming,
ideas developed, groups breaking up and reforming. Many blackboards
are active at once, and as interest is forgotten, they dissolve,
then reform around other topics.
Notice that this representation of a party has no simple
sequential representation, nor would a simple top level rule
base be able to model the range of activities the party can evolve to.
How does "the party" decide what beer to buy, or how long to stay intact,
or whether it will be fun or not? If I were to model a party, I'd
say a parallel system of subcognitive structures would be almost
the only natural way.
As a final note, I find the vision of consciousness being
analogous to people at a party simple and humorous. And somehow,
I've always found God to clothe most truths in humor... am I the only
one who has laughed at the beautiful simplicity of E=MC^2?
David