Information Technology Reference
In-Depth Information
information
c
? That is a relevant implication
A
B
is true in the context
x
just
when if we pick any other pieces of information
y
and
z
such that
y
is relevant
to
z
in the context
x
,thenif
y
determines
A
,then
z
determines
B
.
→
5 What is Relevance?
The concept of relevance occurs in a number of contexts. The most relevant for
us (sorry for the pun) are commonsense reasoning, probability and statistics,
information retrieval (particularly, search of unstructured data bases such as
the WWW to take an extreme example), library science, the law, cognitive
science, epistemology, and linguistics and philosophy of language (particularly,
pragmatics). We cannot possibly run through these all (just google the word
“relevance” - I believe Google has a good relevancy algorithm) so I want to
jump to what I believe is the most relevant work for our purposes here, which
relates to the pragmatics of language.
Pragmatics is one of the three dimensions of natural language, as introduced
by Charles Morris (1946), the other two being syntax and semantics. Put quickly,
syntax has to do with grammar, semantics has to do with meaning, and prag-
matics has to do with use. Paul Grice in his famous John Locke Lectures at
Oxford (1967), printed in Grice (1989), introduced the idea of “conversational
maxims,” saying (p. 27) “Under the category of Relation I place a single maxim,
namely, 'Be relevant.'” Grice goes on to say “Though the maxim itself is terse,
its formulation conceals a number of problems that exercise me a good deal:
questions about what different kinds and focuses of relevance there may be, how
these shift in the course of a talk exchange, how to allow for the fact that sub-
jects of conversation are legitimately changed, and so on.” Grice in fact does
offer anything, at least directly, to answer such questions, and in fact says. “I
find the treatment of such questions exceedingly dicult, and I hope to revert
to them in later work.” To the best of my knowledge Grice never published such
later work. But the linguists Deirdre Wilson and Dan Sperber (1986) turned to
the task of clarifying the concept of relevance, and they have carried on with it
for over a quarter of a century - see Wilson and Sperber (2012).
There is clearly much to be said about their Herculean task and the Herculean
response to it. But I content myself here with this quotation from Wilson and
Sperber (2004).
Intuitively, an input (a sight, a sound, an utterance, a memory) is rel-
evant to an individual when it connects with background information he
has available to yield conclusions that matter to him: say, by answering a
question he had in mind, improving his knowledge on a certain topic, set-
tling a doubt, confirming a suspicion, or correcting a mistaken impression.
In relevance-theoretic terms, an input is relevant to an individual when
its processing in a context of available assumptions yields a positive cog-
nitive effect. A positive cognitive effect is a worthwhile difference to the
individual's representation of the world - a true conclusion, for example.
