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Philosophy and Logic Seminar at LaSorbonne/Centre Pompidou this weekend

From: Harry Halpin <hhalpin@ibiblio.org>
Date: Fri, 13 Apr 2012 21:11:53 +0200
Message-ID: <CAE1ny+7m4oFOcST9nEG+kidxWjh+Xh-mkePt0fO-L3qqbUJvUw@mail.gmail.com>
To: Semantic Web <semantic-web@w3.org>
Saturday 14 April (14h00-17h00) and Sunday 15 April (10h00-14h00)

Logic and the Web

Christopher Menzel
(Texas A&M University)
Department of Philosophy

Patrick J. Hayes
Institute for Human & Machine Cognition
(Sunday only via Teleconference)

Common Logic: An Evolutionary Tale

Traditional first-order logic (TFOL) combines a clean, well-defined,
highly expressive syntax with a clear, simple semantics and any number
of semantically complete proof theories. It is not without good
reason, then, that TFOL is the most popular and widely used framework
for representing information. As is well known, much of first-order
logic can be traced back to the work of Frege (among others). Somewhat
ironically, even though many of Frege’s ontological doctrines are out
of fashion, certain prominent features of the syntax and semantics of
TFOL bear the unmistakable imprint of these doctrines — most notably,
the idea that there is an inviolable gulf between concept and object.
Interestingly, however, regardless of any independent merits of
Frege’s ontology, the corresponding features of TFOL are a positive
liability when faced with the challenge of representing and exchanging
information in an anarchic environment like the World Wide Web. The
topic of my talk discusses how some of these representational
challenges led to evolutionary changes in the syntax and semantics of
TFOL resulting in a first-order framework (now also an ISO
international standard) known as Common Logic that embodies a
decidedly non-Fregean ontology.

In a bit more technical detail: In Common Logic, the traditional TFOL
syntactic categories of variables, individual constants, n-place
predicates and n-place function symbols are dissolved in favor of a
single category of names; and the polarized ontology of concept and
object is replaced by a single category of things. The traditional
syntactic categories reappear only as syntactic roles that names can
play in one context or another. As any string of names in this
language is both a well-formed function term and a well-formed atomic
formula, predication and function application are variably polyadic
(e.g., “pa”, “pab”, “pabc” with the same name in predicate/function
position are all well-formed), self-predication and self-application
are possible (e.g., “pp” and “f(f,a)” are well-formed), and
quantification is syntactically second-order (e.g., “∃p∀x(px ↔ ~xx)”,
and indeed “∃f f(a)x” (where “f(a)” is in predicate position) are both
well-formed). Time permitting, I will also discuss some of the more
advanced features of Common Logic and will briefly touch on some
metatheoretic results for the logic, notably a completeness proof and
a method of translating from this logic into a TFOL framework.

Saturday: LaSorbonne Centre Seminar is in Room Lalande (17 rue de la
Sorbonne, Escalator C, 1sf Floor Left droite) 14h00 to 17h00,

Sunday:  at the Rook Triangle du Centre Pompidou (right of the main )
from 10h00 to 14h00.

Séminaire “Philosophie du Web”

(une initiative soutenue par le Collège des Ecoles doctorales de Paris
1, l’Institut de Recherche et d’Innovation (IRI) du Centre Pompidou et
la revue Implications Philosophiques)
Dirigé par Alexandre Monnin (Université Paris 1
Panthéon-Sorbonne/IRI/INRIA) et Harry Halpin (IRI/W3C)
Received on Friday, 13 April 2012 19:12:22 UTC

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