Copy Link
Add to Bookmark
Report
AIList Digest Volume 5 Issue 183
AIList Digest Friday, 17 Jul 1987 Volume 5 : Issue 183
Today's Topics:
Philosophy - Natural Kinds & Philosophy of Science &
Categorization & Symbol Grounding
----------------------------------------------------------------------
Date: 15 Jul 87 14:19 PDT
From: Tony Wilkie /DAC/ <TLW.MDC@OFFICE-1.ARPA>
Subject: Natural Kinds
I may get sizzled for this, but I will suggest that the term "natural kind",
while a fairly recent addition to the philosophical lexicon, is a conceptual
descendant of Plato`s Forms, and more closely approximated in meaning to
Aristotle's discussions of 'kinds' in his Metaphysics.
Chairs would certainly be a paradigm example of a Platonic Form, and Aristotle
in his Metaphysics used his horse, Bucephalus, as an example in his discussion
of kinds. Given his inclination as sort of a teleological guerilla, Aristotle
would have (and may have) had a tough time separating his 'kinds' concept from
'species' in the biological cases. Still, I think it safe to say that
philosophical discussion of ontology preceded the development of a formal
concept of species.
Tony L. Wilkie <TLW.MDC@Office-1.ARPA>
------------------------------
Date: Thu, 16 Jul 87 15:42:11 EDT
From: mclean@nrl-css.arpa (John McLean)
Subject: Natural Kinds
Even "recent" philosophical discussions of natural kinds go back 20 years
and much further if you count Nelson Goodman's stuff on projectibility of
predicates (why do we assume emeralds are green and not grue, i. e.,
green until the year 2000 and then blue?) or much of the stuff written
in response to Hempel's problem whether a nonblack nonraven could could
count as a confirming instance of the claim that all ravens are black (since
the claim that all P's are Q's is logically equivalent to the claim that
all nonQ's are nonP's). But I think you can also view much of what Plato
had to say about forms and what Aristotle had to say about substance as
being concerned with the problem of natural kinds as well.
However, I think the issue being raised about recognizing penguins,
chairs, etc. goes back to Wittgenstein's _Philosophical_Investigations_:
For if you look at them you will not see something that is common to
all, but similarities, relationships, and whole series of them at
that...I can think of no better expression to characterize these
similarities than "family resemblance"...
John McLean
------------------------------
Date: 16 Jul 87 2207 PDT
From: John McCarthy <JMC@SAIL.STANFORD.EDU>
Subject: re: AIList Digest V5 #181
[In reply to message sent Tue 14 Jul 1987 22:58-PDT.]
The distinction I had in mind between natural kind and cluster is
the presumed existence of as yet unknown properties of a natural
kind.
When I said "doubtful cases are rare", I left myself open to misunderstanding.
I meant that in case of chairs in Timothy's experience doubtful cases
are rare. Therefore, for a child to presume a natural kind on hearing
a word or seeing an object is advantageous, and it will also be advantageous
to built AI systems with this presumption.
Finally, a remark concerning the "symbol grounding" discussion. My
problems with it were mainly quantitative - there was just too much
to follow. I suspect that Stevan Harnad's capacity to follow very
long discussions is exceptional. I would welcome a summary of the
different points of view by someone who did follow it and feels himself
sufficiently uncommitted to any single point of view.
------------------------------
Date: Thu, 16 Jul 87 17:18 EDT
From: Nichael Cramer <nichael@JASPER.PALLADIAN.COM>
Reply-to: Nichael Cramer <NICHAEL%JASPER@LIVE-OAK.LCS.MIT.EDU>
Subject: AIList Digest V5 #182
>>
>> Let's take a step back. Is "Computer Science" a science? -- Sam
>>
There is the old chestnut that one should be leery of any disipline that feels
such a need to justify itself that it appends the term "Science" to its own
name. Witness "Social Science". Or more to the point, "Creation Science"
[sic].
[Standard disclaimer concerning personal nature of views applies]
NICHAEL
Rednecks for Rainforest
------------------------------
Date: 14 Jul 87 22:20:56 GMT
From: mcvax!botter!klipper!biep@seismo.css.gov (J. A. "Biep" Durieux)
Subject: Definition of science and of scientific method.
1) I think this discussion belongs in sci.philosophy.tech, and perhaps in
sci.research, but definitely not in any of the other groups. Please let's
move out of the wrong newsgroups. This article is meant as a merger of
two discussions, one in sci.med (and other places), and one in comp.ai.
Followups will go to sci.philosophy.tech *only*.
2) There are multitudes of definitions for science, and even more usages.
Here I talk just about a rather generally accepted stance.
3) There is craft (what engineers and the like do), art (about which I
don't want to speak), science (the methodically unraveling of the
secrets of the world ("world" in a broad sense), and philosophy (the
necessary building of footholds, standing on which science can be done).
4) Philosophy starts with quarreling about whether God exists, then whether
I exist (some say the other way round - for "God" some read "anything at all"),
then whether an outside world exist, then how we should look at that world
(yielding things like epistemology, ethics, aesthetics, etc.), and,
choosing epistemology, which ways of getting knowledge are there and which
ones have which value. One of these methods (as many philosophers hold)
is reason, and there come logic and mathematics around the corner.
Still much dispute (intuitionism for example - could you give us an intro,
Lambert Meertens? - or "what constitutes a proof", "what is `mathematical
rigour'", etc.) and uncertainty (liars paradox) around, as the means of
thinking are still being defined, so they cannot be used freely yet.
Perhaps that is a good working definition of science: thinking there where
the means for thinking are not yet finished.
5) Science starts (or: sciences start) from the results of the philosophers'
work (unhappily the philosophers aren't ready yet, so those results are
not as sure as they should be, and certainly not as sure as they are often
thought to be by non-philosophical scientists) exploring the world.
6) The definition of "science", and of scientific method, is by its very
nature a philosophical, not a scientifical matter. Otherwise one would
get paradoxes like:
Ockhams razor tells us to throw away any non-necessary principles.
The principle of Ockhams razor is non-necessary.
So let's throw away Ockhams razor.
(Happily, the director of the British Museum will not let you touch it,
but anyway, the case is clear.)
7) The above is highly simplified, but I believe that simple introductions
are wanting on usenet. Too often I fall into a discussion which supposes
knowledge I don't have, of I see some participants don't have.
8) If this spawns serious discussion (only in sci.philosophy.tech, please!)
I would be more than pleased.
--
Biep. (biep@cs.vu.nl via mcvax)
Unix is a philosophy, not an operating system. Especially the latter.
------------------------------
Date: 15 Jul 87 15:45:00 GMT
From: apollo!laporta@beaver.cs.washington.edu (John X. Laporta)
Subject: Re: The symbol grounding problem: "Fuzzy" categories?
In article <3183@venera.isi.edu> smoliar@vaxa.isi.edu.UUCP (Stephen
Smoliar) writes:
>There are probably any number of bindings for BAR
>for which "What is a BAR?" runs >into ... difficulty and for which
>"How can I use a FOO as a BAR?" is the more useful >question. > >In
>an earlier posting, Harnad gave the example of how we classify works
>of >art ... Such classifications may also be susceptible to this
>intermediate level of >interpretation. Thus, you may or may not
>choose to view a particular tapestry >as an allegory ... [or] as a
>pastoral. Such decisions influence the way you see it and >"parse" it
>as part of your artistic appreciation, regardless of whether or not
>your >particular view coincides with that of the creator!
>
>I suspect there is a considerable amount of such relativity in the way we
>detect categories. That relativity is guided not by what the categories
>are or what their features are but by how we intend to put those
>categories to use. (In other words, the issue isn't "What features
>are present?" but "What features do we want to be present?")
Umberto Eco writes in "Euge`ne Sue and _Les Myste`res de Paris_" about this
problem. Sue was a sort of gentleman pornographer in post-Napoleonic France.
One of his series, about a character like the Shadow who worked revenge on
decadent aristocratic evildoers, with a lot of bodice-ripping along the way,
caught on with the newly literate general working public. They consumed his
book in vast quantities and took it as a call to arms so seriously that Paris
was barricaded by people inspired by it. A sex-and-violence pornographic
thriller became a call to political reform and the return of morality.
The relevant semiotic category is "closure." Roughly speaking, a
closed work is one that uses a tight code to tell a tale to an
audience sharply defined by their sharing of that code. Superman
Comics is an example of a closed work. (There is an entertaining study
somewhere of explanations offered by New Guinean tribesmen of a
Superman Comic.) Closed works don't ring, so to speak, with the
resonance of the entire semiotic continuum, while open works do.
Closed works are thus easily subject to gross misinterpretation by
readers who don't share the code in which those works are written.
Open works, on the other hand, enforce their own interpretation. While
there is drift over time in these interpretations, it is far smaller
than the vastly divergent interpretations offered of closed works by
varying interpreters in the same era. Open works connect to the
entire semiotic continuum - indeed, the (broadly) rhetorical methods
(tropoi) they use bespeak a purpose of educating the reader about the
subjects (topoi) they treat. _Remembrance of Things Past_ is an
example of an open work. While a great deal of unfamiliar material and
controversial analysis is offered to any reader of those 3000 pages,
the mere act of reading them enforces what is, for the purpose of
semiotics, a uniform interpretation (read disambiguated topical
hypothesis).
It is very easy to 'use' a closed work by correlating the elements of
an external symbol system with the opaque code the work presents. Of
course, if the 'grounding' of one's symbol system bears no relation to
that which the work employs, one is just as much 'used' by the work as
a consequence. (Imagine, for example, using a rectangular bar of
plastic explosive as a straightedge.)
It is far more difficult to impose an arbitrary interpretation on an
open work, since it contains material that tends to contradict
incorrect or incomplete hypotheses about its topos. For example,
while we are 'told' that Superman comes from the planet Krypton, etc.,
we learn by watching Marcel what his origins are, and while Superman
comes as a given from space, Marcel's character defines itself in our
consciousness by our 'observation' of his life. Furthermore, while
Superman is always Superman, Marcel has an origin and a destiny.
Marcel changes with time, he breaks with Albertine; Superman always
almost, but actually never marries Lois Lane. (Spiderman's recent
marriage to Mary Jane is an interesting twist. Certainly by comparison
with Superman's, Spiderman's story is an open work.)
Historians who based hypotheses about 20th century American atittudes
on an analysis of Superman comics would have to confirm them by
considerable reference to external sources, while students of early
20th century France would likely use _Remembrance of Things Past_ to
confirm their ideas.
IN SUMMARY: The relativity of categorization is an inverse index of
the 'openness' of the thing categorized. Dr. Morbius in "Forbidden
Planet" was able to divine the purpose of Krell instrumentation
because the science on which it was founded, while more advanced than
his own, shared the same basis in physical reality and hypothesis
testing. The space-given monolith in "2001" is indecipherable (a real
'black box', but with undefined input and output), and thus can be
'used' for any purpose at all.
------------------------------
Date: 13 Jul 87 18:16:06 GMT
From: linus!philabs!sbcs!bnl!allard@husc6.harvard.edu (rick allard)
Subject: Re: The symbol grounding problem: Again... grounding?
In article <931@mind.UUCP> harnad@mind.UUCP (Stevan Harnad) writes:
>Categorization preformance (with all-or-none categories) is highly reliable
>(close to 100%) and MEMBERSHIP is 100%. ...
Why add this clause about "real" membership? Isn't the bulk of the
discussion about us humble humans doing the categorizing? If we do
start wondering about this larger realm, does it bear on categorizing?
Rick
--
ooooooooooooootter#spoon in bowl
!!!!!!!!!!!!& RooM &
!!!!!!!!!!!!R oooo M
------------------------------
Date: 15 Jul 87 19:08:35 GMT
From: diamond.bbn.com!aweinste@husc6.harvard.edu (Anders Weinstein)
Subject: Re: The symbol grounding problem meta-discussion
Since I will shortly be posting a follow-up to Harnad's last reply to me on
the SGP, I guess I ought to address the meta-discussion.
I think that different standards apply in the two domains in which this
discussion has been taking place.
I recognize that AI-List subscribers rightfully expect some selectivity from
an edited digest, and I will understand completely if the moderator chooses
not to redistribute my follow-up because the volume on this subject has
exceeded the limits demanded by his readership.
On the other hand, I see no justification for attempting to squelch the
discussion on the Usenet side of things (from which I am participating). This
unmoderated forum is avowedly anarchic, and the wishes of a supposed majority
are irrelevant -- perhaps no single topic interests a majority of readers. If
you're not interested in a discussion that's clearly appropriate for this
newsgroup, the right thing to do is just ignore it. The software makes it
easy to "kill" a topic you don't care about; do so, and you'll never even
*see* the messages. I really don't understand the problem.
Anders Weinstein
BBN Labs
------------------------------
Date: 15 Jul 87 20:00:29 GMT
From: diamond.bbn.com!aweinste@husc6.harvard.edu (Anders Weinstein)
Subject: Re: The symbol grounding problem
In a previous message, I was prompted by Stevan Harnad's postings to try to
explain something I find very interesting, namely, why the psychology of
categorical perception won't do much to illuminate the difficult question of
how formal symbols should be semantically interpreted, i.e. what the symbols
really *mean*. Harnad sent a long reply (message 972@mind.UUCP) explaining
the nature of his approach in great detail. The upshot, I think, is that in
spite of some of the rhetoric about "symbol grounding", Harnad's project is
not really *attempting* to do any such thing. It merely aims to discover the
mechanisms underlying certain recognition skills. Since this more modest aim
was precisely what I was urging, I am satisfied that there is no major
disagreement between us.
I want to make clear that I am not here trying to pose any *objection* to
Harnad's model considered as a bit of psychology. I am only trying to
downplay its significance for philosophical issues.
Remember that the traditional conception of "meanings" or "concepts" involves
certain properties: for example, meanings are supposed to contain a criterion
which determines the correct application of the term, in effect defining the
metaphysical essence of the concept in question; they are supposed to serve
as elementary constituents of more complex concepts and thoughts; and they
are supposed to license analytic implications, such as "all bachelors are
unmarried". Since none of these properties seem to be required of the
representations in Harnad's theory, it is in a philosophical sense *not* a
theory of "concepts" or "meanings" at all. As Harnad should be be happy to
concede.
But I want to emphasize again an important reason for this which Harnad
seemed not to acknowledge. There is a vast difference between the
quick, observational categorization that psychologists tend (rightly) to
focus on and the processes involved in what might be called "conclusive"
classification. This is the difference between the ability to recognize
something as fish-like in, say, 500 milliseconds, and the ability to
ascertain that something *really* is a fish and not, say, an aquatic mammal.
Now the former quick and largely unconscious ability seems at least a
plausible candidate for revealing fundamental cognitive mechanisms. The
latter, however, may involve the full exercise of high-level cognition --
remember, conclusive classification can require *years* of experiment,
discussion and debate, and potentially involves everything we know. The
psychology of conclusive categorization does *not* deal with some specialized
area of cognition -- it's just the psychology of all of science and human
rationality, the cognitive scientist's Theory of Everything. And I don't
expect to see such a thing any time soon.
Confusion can result from losing sight of the boundary between these two
domains, for results from the former do not carry over to the latter. And I
think Harnad's model is only reasonably viewed as applying to the first of
these. The rub is that it seems that the notion of *meaning* has more to do
with what goes on in the second. Indeed, what I find most interesting in all
this is the way recent philosophy suggests that concepts or meanings in the
traditional sense are essentially *outside* the scope of forseeable psychology.
Some other replies to Harnad:
Although my discussion was informed by Quine's philosophy in its reference to
"meaning holism", it was otherwise not all that Quinean, and I'm not sure
that Quine's highly counter-intuitive views could be called "standard." Note
also that I was *not* arguing from Quine's thesis of the indeterminacy of
translation; nor did I bring up Putnam's Twin-Earth example. (Both of these
arguments would be congenial to my points, but I think they're excessively
weighty sledgehammers to wield in this context). The distinction between
observational and "conclusive" classification, however, does bear in mind
Putnam's points about the the non-necessity of stereotypical properties.
I also don't think that philosophers have been looking for "the wrong thing
in the wrong way." I think they have made a host of genuine discoveries about
the nature of meaning -- you cite several in your list of issues you'd prefer
to ignore. The only "failure" I mentioned was the inability to come up with
necessary and sufficient definitions for almost anything. (Not at all, by the
way, a mere failure of "introspection".)
I *do* agree that the aims of philosophy are different than those of
psychology. Indeed, because of this difference of goals, you shouldn't feel
you have to argue *against* Quine or Putnam or even me. You merely have to
explain why you are side-stepping those philosophical issues (as I think you
have done). And the reason in brief is that philosophers are investigating
the notion of meaning and you are not.
Anders Weinstein
BBN Labs
------------------------------
End of AIList Digest
********************
