The concept of relevance is studied in many different fields, including cognitive sciences,
logic, and library and information science. Most fundamentally, however, it is studied
in epistemology. Different theories of knowledge have different implications for what is considered
relevant and these fundamental views have implications for all other fields as well.
Definition "Something is relevant to a task if it increases
the likelihood of accomplishing the goal, which is implied by T.".
A thing might be relevant, a document or a piece of information may be relevant. The
basic understanding of relevance does not depend on whether we speak of "things" or
"information". Epistemology
If you believe that schizophrenia is caused by bad communication between mother and child,
then family interaction studies become relevant. If, on the other hand, you subscribe to a
genetic theory of relevance then the study of genes becomes relevant. If you subscribe
to the epistemology of empiricism, then only intersubjectively controlled observations
are relevant. If, on the other hand, you subscribe to feminist epistemology, then the sex of
the observer becomes relevant. Epistemology is not just one domain among
others. Epistemological views are always at play in any domain. Those views determine
or influence what is regarded relevant. Relevance logic
In formal reasoning, relevance has proved an important but elusive concept. It is important
because the solution of any problem requires the prior identification of the relevant elements
from which a solution can be constructed. It is elusive, because the meaning of relevance
appears to be difficult or impossible to capture within conventional logical systems. The obvious
suggestion that q is relevant to p if q is implied by p breaks down because under standard
definitions of material implication, a false proposition implies all other propositions.
However though 'iron is a metal' may be implied by 'cats lay eggs' it doesn't seem to be relevant
to it the way in which 'cats are mammals' and 'mammals give birth to living young' are
relevant to each other. If one states "I love ice cream," and another person responds "I
have a friend named Brad Cook," then these statements are not relevant. However, if one
states "I love ice cream," and another person responds "I have a friend named Brad Cook
who also likes ice cream," this statement now becomes relevant because it relates to
the first person's idea. More recently a number of theorists have sought
to account for relevance in terms of "possible world logics" in intensional logic. Roughly,
the idea is that necessary truths are true in all possible worlds, contradictions are
true in no possible worlds, and contingent propositions can be ordered in terms of the
number of possible worlds in which they are true. Relevance is argued to depend upon the
"remoteness relationship" between an actual world in which relevance is being evaluated
and the set of possible worlds within which it is true.
Application Politics
During the 1960s, relevance became a fashionable buzzword, meaning roughly 'relevance to social
concerns', such as racial equality, poverty, social justice, world hunger, world economic
development, and so on. The implication was that some subjects, e.g., the study of medieval
poetry and the practice of corporate law, were not worthwhile because they did not address
pressing social issues. Economics
The economist John Maynard Keynes saw the importance of defining relevance to the problem
of calculating risk in economic decision-making. He suggested that the relevance of a piece
of evidence, such as a true proposition, should be defined in terms of the changes it produces
of estimations of the probability of future events. Specifically, Keynes proposed that
new evidence e is irrelevant to a proposition, given old evidence q, if and only if p/q & e
= p/q and relevant otherwise. There are technical problems with this definition,
for example, the relevance of a piece of evidence can be sensitive to the order in which other
pieces of evidence are received. Cognitive science and pragmatics
In 1986, Dan Sperber and Deirdre Wilson drew attention to the central importance of relevance
decisions in reasoning and communication. They proposed an account of the process of
inferring relevant information from any given utterance. To do this work, they used what
they called the "Principle of Relevance": namely, the position that any utterance addressed
to someone automatically conveys the presumption of its own optimal relevance. The central
idea of Sperber and Wilson's theory is that all utterances are encountered in some context,
and the correct interpretation of a particular utterance is the one that allows most new
implications to be made in that context on the basis of the least amount of information
necessary to convey it. For Sperber and Wilson, relevance is conceived as relative or subjective,
as it depends upon the state of knowledge of a hearer when they encounter an utterance.
Sperber and Wilson stress that this theory is not intended to account for every intuitive
application of the English word "relevance". Relevance, as a technical term, is restricted
to relationships between utterances and interpretations, and so the theory cannot account for intuitions
such as the one that relevance relationships obtain in problems involving physical objects.
If a plumber needs to fix a leaky faucet, for example, some objects and tools are relevant
and others are not. And, moreover, the latter seems to be irrelevant in a manner which does
not depend upon the plumber's knowledge, or the utterances used to describe the problem.
A theory of relevance that seems to be more readily applicable to such instances of physical
problem solving has been suggested by Gorayska and Lindsay in a series of articles published
during the 1990s. The key feature of their theory is the idea that relevance is goal-dependent.
An item is relevant to a goal if and only if it can be an essential element of some
plan capable of achieving the desired goal. This theory embraces both propositional reasoning
and the problem-solving activities of people such as plumbers, and defines relevance in
such a way that what is relevant is determined by the real world rather than the state of
knowledge or belief of a particular problem solver.
Law
The meaning of "relevance" in U.S. law is reflected in Rule 401 of the Federal Rules
of Evidence. That rule defines relevance as "having any tendency to make the existence
of any fact that is of consequence to the determinations of the action more probable
or less probable than it would be without the evidence." In other words, if a fact were
to have no bearing on the truth or falsity of a conclusion, it would be legally irrelevant.
Library and information science
This field has considered when documents retrieved from databases are relevant or non-relevant.
Given a conception of relevance, two measures have been applied: Precision and recall:
Recall = a : X 100%, where a = number of retrieved, relevant documents, c = number
of non-retrieved, relevant documents. Recall is thus an expression of how exhaustive a
search for documents is. Precision = a : X 100%, where a = number
of retrieved, relevant documents, b = number of retrieved, non-relevant documents.
Precision is thus a measure of the amount of noise in document-retrieval.
Relevance itself has in the literature often been based on what is termed "the system's
view" and "the user's view". Hjørland criticize these two views and defends a "subject knowledge
view of relevance". See also
Source criticism Description
Distraction Information-action ratio
Information overload Intention
Relevance theory References
Gorayska B. & R. O. Lindsay. The Roots of Relevance. Journal of Pragmatics 19, 301–323.
Los Alamitos: IEEE Computer Society Press. Hjørland, Birger. The foundation of the concept
of relevance. Journal of the American Society for Information Science
and Technology, 61(2), 217-237. Keynes, J. M.. Treatise on Probability. London:
MacMillan Lindsay, R. & Gorayska, B. Relevance, Goals
and Cognitive Technology. International Journal of Cognitive Technology, 1,, 187–232
Sperber, D. & D. Wilson Relevance: Communication and Cognition. 2nd edition. Oxford: Blackwell.
Sperber, D. & D. Wilson. Précis of Relevance: Communication and Cognition. Behavioral and
Brain Science, 10, 697–754. Sperber, D. & D. Wilson. Relevance Theory.
In Horn, L.R. & Ward, G. 2004 The Handbook of Pragmatics. Oxford: Blackwell, 607-632.
http:www.dan.sperber.fr/?p=93 Zhang, X, H.. A Goal-Based Relevance Model
and its Application to Intelligent Systems. Ph.D. Thesis, Oxford Brookes University, Department
of Mathematics and Computer Science, October, 1993.
External links Malcolm Gladwell - Blink - full show: TVOntario
interview regarding "snap judgements" and Blink