From newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.ecf!utgpu!cs.utexas.edu!swrinde!sdd.hp.com!mips!dimacs.rutgers.edu!rutgers!hsdndev!husc-news.harvard.edu!zariski!zeleny Tue Nov 26 12:31:16 EST 1991
Article 1475 of comp.ai.philosophy:
Xref: newshub.ccs.yorku.ca rec.arts.books:10357 sci.philosophy.tech:1041 comp.ai.philosophy:1475
Path: newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.ecf!utgpu!cs.utexas.edu!swrinde!sdd.hp.com!mips!dimacs.rutgers.edu!rutgers!hsdndev!husc-news.harvard.edu!zariski!zeleny
>From: zeleny@zariski.harvard.edu (Mikhail Zeleny)
Newsgroups: rec.arts.books,sci.philosophy.tech,comp.ai.philosophy
Subject: The Philosophical Foibles of John McCarthy
Summary: no more Mr Nice Guy
Keywords: circumscription, ontology, syntax, semantics, Occam's Razor
Message-ID: <1991Nov21.145350.5725@husc3.harvard.edu>
Date: 21 Nov 91 19:53:45 GMT
References: <1991Nov15.003438.11323@grebyn.com> <1991Nov15.160741.5495@husc3.harvard.edu> <JMC.91Nov20144012@SAIL.Stanford.EDU>
Organization: Dada
Lines: 101
Nntp-Posting-Host: zariski.harvard.edu

In article <JMC.91Nov20144012@SAIL.Stanford.EDU> 
jmc@SAIL.Stanford.EDU (John McCarthy) writes:

>In-Reply-To: john@publications.ccc.monash.edu.au's 
>message of 20 Nov 91 04:48:37 GMT

JMC:
>It was mistaken of me to let Michael Zeleny get away with using
>my not answering one of his questions (because I didn't understand it)
>as an excuse for not offering specific arguments against Dennett.
>Dennett's arguments for Dennett's positions can stand up by themselves
>and don't require supplements from me.

My specific arguments against Dennett's ignorance and/or charlatanism are
to be found in a preceding article; for the time being, I shall occupy
myself with you, limiting myself to the lexicon used and concepts expressed
in your published writings in order to facilitate your understanding of my
points.  Make no mistake, Professor: this is no mere *ad hominem* appeal; I
address you because you represent a perniciously false scientific theory,
rather than because you have a white beard, wear Stars and Stripes on your
lapel, or espouse reactionary political views.  Recall also your own claim
while defending your conception of Western culture: this topic has a
tradition of vigorous debate.  You asked for it; now try to enjoy it.

I assume that your acquaintance with Alonzo Church's writings extends at
least to his 1940 monograph "The Calculi of Lambda-conversion", the
appreciation of which, as recorded in your 1960 ACM article, resulted in
your development of LISP, and amounted to your most impressive intellectual
accomplishment.  Had you bothered to pay heed to Church's later logical and
philosophical work, you might have saved yourself the embarrassment that is
your theory of circumscription.

Consider the following: your stated goal in the theory's development is to
formalize a certain ontological assumption, i.e. that "the objects that can
be shown to follow to have a certain property P by reasoning from certain
facts A are all the objects that satisfy P" (cited from your 1980 article
in "Artificial Intelligence"); in order to capture this assumption, which
you recently characterized as a form of Occam's Razor, writing $A(\Phi)$
for the result of replacing all occurrences of $P$ in $A$ by the predicate
expression $\Phi$, you introduce as ``the circumscription of $P$ in $A(P)$
... the sentence schema $$A(\Phi) \land \forall \overline{x} \dot
(\Phi(\overline{x}) \supset P(\overline{x})) \supset \forall \overline{x}
\dot (P(\overline{x}) \supset \Phi(\overline{x})) ,$$'' interpreting the
condition ``as asserting that the only tuples $(\overline{x})$ that satisfy
$P$ are those that have to -- assuming the sentence $A$.'' (op. cit.)

Now, the specious bit of prestidigitation represented in the above claim,
is your silent transition from talking about a property P and certain facts
A to the (extensional) first-order predicate P and a sentence A.  Had you
bothered to pay attention to the Quine--Church discussion of ontological
commitment in the late Forties, you wouldn't have failed to recognize that,
in passing from intensional entities like properties and observables like
facts, to extensional entities like predicates and syntactical ones like
sentences, respectively, you already implicitly circumscribe your ontology,
begging the question of ontological commitment.  Now, you could argue that
under the formalist assumption that a theory is reducible to its syntax,
you haven't done anything wrong in tacitly dispensing with the semantical
considerations; however, on this view you aren't entitled to talk about
facts and objects at all.  Facts and objects exist before all theoretical
descriptions thereof, and semantics is the only bridge between the latter
and the former; ignore it, and your grand theory is reduced to a mere
*flatus vocis*.

There exist even more fundamental problems implicit in your approach, in
that it relies on a simplistic application of Occam's razor.  As noted
Church in his 1951 article, "The Need for Abstract Entities", not every
subtraction from the entities that a theory assumes is a reduction in the
variety of entities, and, more importantly, the need of ontological
parsimony should be balanced by the need of the workability, simplicity,
and generality of the theory; were you to succeed in formalizing a
principle stipulating the former, there's no reason to suppose that the
latter would lend themselves to easier formalization than the much more
restricted general problem of algebraic simplification, currently
considered to be intractable.

To sum, your program is flawed both methodologically and formally.  Please
note that if I bother to spend my limited time on explaining the above,
it's only because I hope that your credibility, unlike that of Dennett, can
still be salvaged.

>--
>John McCarthy, Computer Science Department, Stanford, CA 94305
>*
>He who refuses to do arithmetic is doomed to talk nonsense.

I repeat my question: can your computers do arithmetic?

'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`
`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'
: Qu'est-ce qui est bien?  Qu'est-ce qui est laid?         Harvard   :
: Qu'est-ce qui est grand, fort, faible...                 doesn't   :
: Connais pas! Connais pas!                                 think    :
:                                                             so     :
: Mikhail Zeleny                                                     :
: 872 Massachusetts Ave., Apt. 707                                   :
: Cambridge, Massachusetts 02139                                     :
: (617) 661-8151                                                     :
: email zeleny@zariski.harvard.edu or zeleny@HUMA1.BITNET            :
:                                                                    :
'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`
`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'`'


