From newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!netnews.upenn.edu!libra.wistar.upenn.edu Sun Dec  1 13:06:24 EST 1991
Article 1727 of comp.ai.philosophy:
Path: newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!netnews.upenn.edu!libra.wistar.upenn.edu
>From: weemba@libra.wistar.upenn.edu (Matthew P Wiener)
Newsgroups: comp.ai.philosophy
Subject: Re: Dennett on Edelman--what a total loss
Message-ID: <57730@netnews.upenn.edu>
Date: 28 Nov 91 19:30:31 GMT
References: <1991Nov21.145350.5725@husc3.harvard.edu> <JMC.91Nov24203029@SAIL.Stanford.EDU> <57569@netnews.upenn.edu> <1991Nov27.031545.11235@bronze.ucs.indiana.edu>
Sender: news@netnews.upenn.edu
Reply-To: weemba@libra.wistar.upenn.edu (Matthew P Wiener)
Organization: The Wistar Institute of Anatomy and Biology
Lines: 119
Nntp-Posting-Host: libra.wistar.upenn.edu
In-reply-to: chalmers@bronze.ucs.indiana.edu (David Chalmers)

In article <1991Nov27.031545.11235@bronze.ucs.indiana.edu>, chalmers@bronze (David Chalmers) writes:
>In article <57569@netnews.upenn.edu> weemba@libra.wistar.upenn.edu (Matthew P Wiener) writes:
>>Dennett dismisses Edelman completely, with the claim that Edelman's
>>work shows the folly of someone working in the cognitive sciences
>>without knowing everything.

>That's incorrect.  Dennett likes and respects Edelman's work, even
>though he thinks that it's ultimately unsuccessful.  The footnote on
>page 268 is a little crass, with remarks that border on the ad hominem,

Amazing.  You call me incorrect, and then start citing exactly what it
was that led to me write >> above.

>such as "Edelman has misconstrued, and then abruptly dismissed, the
>work of many of his potential allies, so he has isolated his theory
>from the sort of sympathetic and informed attention it needs if it is
>to be saved from its errors and shortcomings".  But it's also correct.

His theory will stand or fall on its own merits.  Not on whether he
fills his books with wonderful or even accurate descriptions of other
theories-in-progress.  If Dennett thinks that Edelman is salvageable,
then why does he think it's ultimately unsuccessful?  I'm baffled.

>Edelman's treatment of connectionism, for instance -- a school of
>thought that is on the same wavelength, whether he accepts it or not --
>is superficial and uninformed enough to be almost humourous.

Huh???  Edelman does not treat connectionism.  There is one reference
to it in his trilogy, and he says the models lack the precise neuro-
anatomical detail that he wants in a brain/mind model.  No more, no
less.

>>And he also professes a very scientific wait-and-see attitude--after
>>the Edelman based-models get implemented and tested, he'll only then
>>condescend to evaluate them.  As if digital computation hasn't had
>>decades of coming up short?

>Nothing that Edelman proposes is outside the capacities of digital
>computation -- just as nothing that connectionism proposes is, either.
>Digital computation has this nice property of being universal, so that
>unless you have strong arguments about why very low-level processes
>might be uncomputable -- arguments of the kind Penrose would like to
>have but doesn't -- then there is little reason to reject the
>assumption that the behaviour of biological systems is computable.

Digitial computation is not as universal as you are blanketly asserting,
and Penrose knows this.  I mentioned this in a previous article: quantum
gravity might not be computable.  A computational approach to a quantum
field theoretic sum over four-manifolds runs into the unsolvability of
recognizing when a four-manifold is trivial.  Actually, I don't know if
anyone has shown that basic QFT is computable--people mostly just recog-
nize when the relevant sums have converged for all practical purposes.

The work of Deutsch, Landauer, Feynman, Margolus, etc has--well `shown'
is a bit strong, but `suggested' is a bit weak--anyway, they have
indicated that quantum mechanical computation is, in principal, a far
superior beastie, when it comes to speed, than classical Turing compu-
tation.

Note that there are two levels of computational difficulty addressed
here.  The former is about non-recursive possibilties, the latter
addresses speedup issues of known computation.  But I suspect Penrose
is interested in generalizing the latter from artificial Turing-based
models until it becomes an actual QFT non-recursive computation.

In short, there is good physical speculation behind the notion that
Church's thesis is on its way out.

>Edelman doesn't even begin to make the case.  He just makes a few
>waffly appeals to irrelevant arguments by Putnam and Searle, and then
>argues that no Turing machine could possibly represent all the possible
>events that might come up in a cognitive system -- not recognizing for
>a moment that TM's needn't be restricted to explicit representation.

This is pretty funny.  When Dennett dismisses Edelman, it's "correct",
but when Edelman does the same, it's "waffly" and "irrelevant".  And
this has nothing to do with whom you're rooting for?  Remember, none
of us know who is really right in the end.

Let me spell something out, which I was discussing in e-mail with
someone: I thought Prof McCarthy's complaint about Dreyfus et al, that
they don't do enough AI homework, was ridiculous.  I thought I'd make
a point that AI folks don't do enough neurological homework, and so
I picked Dennett as being closer to the middle--he at least sometimes
does his neurological homework--and I was surprised and annoyed at the
hatchet job Dennett did on Edelman.  I suppose I shouldn't have been
surprised--he's done this hatchet job before, but I'd forgotten about
it.  (See, eg, the end of his "Cognitive Wheels" essay in the Boden
anthology.)

>He comes close to saddling AI researchers with the ridiculously strong
>claim that "the brain is a Turing machine" (a claim that I note has
>been bandied about a number of times in this newsgroup, almost always
>by anti-AI proponents looking for straw figures).

He comes close to saddling AI researchers with this claim, since AI
researchers have periodically come close to it.  But fortunately the
whole issue of AI researchers is irrelevant to Edelman.

>						    All AI needs to hold
>is that brain processes can be simulated by digital computation -- a
>claim that Edelman doesn't come close to refuting.

Why does he need to?  Would Isaac Newton have been improved with an
explanation of why orrerey construction is not the same as an under-
standing of gravitation?  Edelman is interested in the biological
basis of our minds.  It is merely the vagaries of modern intellectual
history that force him to explain why he is in the "let's understand
gravity" camp as opposed to the "let's construct orreries" school.

>						     At the end of the
>day, he's just another guy with a computable theory, albeit one that is
>particularly sophisticated in some ways.

And grounded in the structure of actual brains, and loaded with evolu-
tionary plausibility.  That's not "just another guy".  These aren't just
"some ways" of being sophisticated.
-- 
-Matthew P Wiener (weemba@libra.wistar.upenn.edu)


