Re: [CL] The Decidability Fetish
Philippe, Bill, et al.,
The word "ontology" is a relatively new term even
in philosophy. Aristotle established the subject,
but he didn't use that word. It was never popular
among logicians, and it only began to be used in
the computer field in the mid 1980s. But it has
now become a hot buzz word.
PM> Wouldn't you have the following implied by
> simply saying that an ontology is a shared
> collection of formal definitions and axioms?
Yes, that is what logicians have always called it.
But the hype mongers need something to hype.
And by the way, following are some excerpts from
a book review that I just finished. It shows how
much confusion is floating around about ontology,
semantics, and related topics. (The book, by the
way, is about computational linguistics, but I
won't say anything more about it until the review
has appeared in print.)
John
___________________________________________________
[The first excerpt below is the concluding paragraph
of the review, which shows that I was trying to write
a fairly favorable review of the book as a whole.
The second excert shows that the authors of the book
were confused about model-theoretic semantics because
none of the presentations used the word "ontology".
And the third excerpt shows that some linguists don't
know much about the history of semantics.]
Despite the historical and philosophical inaccuracies,
this is a valuable textbook on computational linguistics.
Its greatest strength is its engineering contribution,
and its greatest weakness is the constant bickering with
linguists and logicians who study different aspects of
the rich and complex subject of language. Humans and
machines require both logical and lexical processing for
language understanding, and the authors could better
inform students by showing what their approach does best
than by trying to limit the range of topics linguists
are allowed to explore.
...
The following passage indicates a serious misunderstanding:
First, we maintain that reference is relevant for the study
of coreference and anaphora... relations in text. Second,
while we agree that truth plays no role in the speaker's
processing of meaning, we are also aware of the need to
"anchor" language in extralinguistic reality. Formal
semanticists use truth values for this purpose. We believe
that this task requires a tool with much more content,
and that an ontology can and should serve as such a tool.
First, logicians do not use truth values to anchor language in
reality; they use references, which are resolved to entities
(objects, properties, and events) in some situation. Second,
truth values are not primary, but derived from the mapping of
linguistic references to actual entities; a sentence is true
if and only if the linguistic configuration of references
and relations conforms to the extralinguistic configuration
of entities. Third, every logician from Aristotle to the present
has insisted that an ontology of every general term is essential
to determine the correct mapping from language to reality.
Aristotle himself never used the word _ontology_, even though
he created the subject; logicians are more likely to use the
words _theory_, _axiomatization_, or _conceptualization_ as
synonyms for what [the authors of the book] call an ontology.
...
Chapter 3 is a brief history of semantics, but it is distorted
by the fact that the word _semantics_ was not coined until
the end of the 19th century. The subject matter, however,
was established by Aristotle in the books _Categories_,
_On Interpretation_, _Analytics_, _Rhetoric_, and _Poetics_.
Under the name of logic or theory of signs, the subject
was thoroughly developed by the Hellenistic and medieval
philosophers. Most books on logic before the 20th century
devoted at least half their text to conceptual analysis and
ontology. The truncated view of history ignores two thousand
years of research:
* Frege is credited with the distinction between extension and
intension, but those words are Hamilton's translation of the
17th century _étendue_ and _compréhension_, which were just
new names for a distinction that had been analyzed in detail
by Aristotle and the medieval scholastics.
* The citations for the "dawn of metalanguage" are to the 1950s.
But Aristotle's theory of definition in terms of genus and
differentiae is metalanguage, and so is his theory of syllogisms
for analyzing the components of meaning. The scholastics
introduced the terms _first intentions_ for language about
physical objects (e.g., "Homo est animal") and _second
intentions_ for language about language (e.g., "Homo est
species").
* Katz and Fodor are given well deserved credit for being the
first in the Chomskyan school to integrate a componential
analysis of word meaning with a compositional analysis of
sentence meaning. Ockham (1323), however, combined both
componential and compositional analyses to determine the
truth conditions for Latin sentences. He not only anticipated
Frege's compositionality and Tarski's model theory, he went
beyond them by applying the techniques to a natural language
instead of an artifical one.
* Kamp did not "add to the agenda of formal semantics a treatment
of coreference and anaphora." The "donkey sentences" that Kamp
analyzed were English translations of examples used by the
scholastics for analyzing similar phenomena.
* The modern history is just as flawed. They claim that first-order
predicate calculus (FOPC) has failed "to have made a historical
impact." In fact, FOPC is the foundation for the SQL databases
that run the world economy. That is certainly an impact.