🚀 go-pugleaf

In article <7853@portia.Stanford.EDU>, dove@portia.Stanford.EDU (Dav Amann) writes:
> Recently, several posters have debated the concept of thinking
> machines without explicitly discussing thought.  We all know that we
> think but I doubt that many individuals can articulate what it means
> to think.

I doubt that *any* individuals can articulate what thinking is, any
more than a fish can comprehend that water is wet. 

****

One fringe benefit of being largely ignorant of both metaphysics and
AI is being blissfully unaware of all the ways I am not supposed to
think. Exercising this freedom tonight I had the idea (probably not
original) that an anology may exist between the questions: "Can
machines think?" and "Are viruses alive?"

A virus is simply a protein coat around some genetic material. If it
is floating in a sterile environment it can't metabolize any available
nutrients the way bacteria do. It doesn't reproduce, it doesn't
respond to stimuli, it is an inert speck of macromolecules (albeit
a highly organized speck). In effect, the virus doesn't possess
sufficient causal structure to qualify as "life" in a disorganized
environment.

However, place the virus in the right environment (i.e., a host) and
it mechanistically attaches itself to receptors on host cells by
passively responding to intermolecular attractive forces. Its protein
coat dissolves mechanistically, and its genetic material enters the
host cell and alters its metabolism. As a result, the host cell
generates many copies of the original virus, then ruptures.

In the environment of the host, the virus sure looks like life.
Outside the host it does not. Therefore, whether we choose to consider
the virus "alive" depends on our frame of reference. To an alien
biologist from another planet who has no knowledge of suitable host
organisms, the information in the virus' structure would be so much
nonsense. In a sense, the virus requires a host to "ground" the
information represented in its internal structure. In other words,
a virus is like "life" with a removable context, apart from which
it becomes "non-life". Life with an on-off switch, as it were.

Now consider a very complex symbol-processing system, say one that
could make a good showing in the "Chinese Room", and moreover, one
that implements statistical pattern-matching algorithms giving it some
"learning" ability. Now, when interacting with chinese speakers,
the SPS could give a fairly convincing imitation of "thinking".
But is it thinking? The Chinese Room argument is supposed to
demonstrate conclusively that the SPS does not think. Assume
Searle is correct, and the SPS does not think. In what way, then,
does its failure to think constrain its possible behaviors?

Let us view the relationship between a symbol-processing system and
human minds as analogous to the relationship between a (benign) virus
and its host. Apart from the host, the virus is nothing, but while
interacting with the host it satisfies enough of the requirements of
"life" to be essentially alive. The virus effectively abstracts, or
mirrors, some of the essential causal structure of the host, so that
in combination with the host it can display highly complex, almost
purposive, behaviors.

So too the SPS abstracts or mirrors some of the essential causal
structure of the human mind that created it. It does not abstract
enough of that structure to "stand on its own", i.e., if we merely
print out its list of machine instructions we do not see anything
vaguely resembling "thinking", and neither can the SPS even imitate
thinking in the wrong environment. And yet, while interacting with the
appropriate "hosts", the SPS is capable of arbitrarily complex
behaviors, perhaps indistinguishable (in an arbitrarily complex SPS)
from the behavior of the minds that created it.

So perhaps a useful way to view symbol processing systems is not as
"thinking systems", but rather, "mind viruses".  (My apologies to Dr.
Rapaport if he has already published a series of papers exploring this
very notion!) :-)

> Etymologysts understand a lot about termites but they cannot explain
> why five termites together will build arches the Romans  would be
> proud of.  The whole is more than the sum of its parts.

If we view "mind" as an emergent property, or epiphenomenon, of
"brain", then doesn't that mean we have no way to point to any
tangible structure in the brain and say "this produces mind" or "that
is mind"? (Because an emergent property, by definition, has no tidy
basis in the structure of any part; it only emerges when all the parts
get together. This may, of course, be only an artifact of our
conceptual deficiency.)

Or in other words, perhaps we have no way even in principle to elicit
the causal mechanisms that give rise to mind? The flip side to that
argument is, of course, that we have no way to arbitrarily restrict
the underlying causal mechanisms that could give rise to "mind" as an
epiphenomenon. Or even which causal aspects of the brain give rise to
"mind". Why, then, couldn't "mind" just as well be an epiphenomenon of
(sufficiently complex) "program"? I.e., if we can't say just how the
brain gives rise to mind, how can we be so sure programs can't do it
to? I don't see how the Chinese Room addresses this at all.

Dan Mocsny
dmocsny@uceng.uc.edu