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  • 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

The concept of relevance is studied in many different fields, including cognitive sciences,

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