Relevance: Language, Semantics, Philosophy

The literature within library and information science (LIS) on relevance comes primarily from the subfields of information retrieval and information systems design. This literature has developed over time from an orthodoxy that has focused on relevance as an objective measure to a comprehension of the dynamic nature of relevance judgment. Other literatures, such as those of the philosophy of language and semantics, also have offered cogent thought that could and should be incorporated into LIS. This thought has broadened discussion to the context in which relevance is assessed, the speech acts that are evaluated, and the dialogic element of human communication. An individual may use any number of ways to begin an examination of relevance. One beginning is provided by Fred Dretske in his Knowledge and the Flow of Information. Dretske acknowledges the usefulness of quantitative theory applied to information but asserts that such theory is limited in that it cannot elucidate the nature of meaning or tell us about the meaning of a particular statement. He says that “if we consult a dictionary, we find information described most frequently in terms of “intelligence,” “news,” “instruction,” and “knowledge.” These terms are suggestive. They have a common nucleus. They all point in the same direction—the direction of truth. Information is what is capable of yielding knowledge, and since knowledge requires truth, information requires it also” (Dretske, 1981, p. 45). Dretske’s notion may make us wonder about the connection between information and knowledge. The role of relevance as it relates to knowledge will recur in this paJohn M. Budd, School of Information Science and Learning Technologies, University of Missouri-Columbia, 303 Townsend Hall, Columbia, MO 65211 448 library trends/winter 2004 per, but some background should guide this exploration of the philosophy of relevance. Fortunately for us, Stefano Mizzaro (1997) undertook an exhaustive review of the information science (IS) literature relating to relevance. His work renders a descriptive literature review here unnecessary; readers should consult his article and its extensive bibliography. In setting the tone for his review, Mizzaro acknowledged that IS approaches to relevance tend to cluster around two groups—one centering on the object, or bit of information, and the other centering on the human element. The first group (the object cluster) includes three entities according to Mizzaro: a document, a surrogate (or representation of a document), and information (or what the reader apprehends from a document). The second group includes a problem faced by the information-seeker, an information need (defined as a mental representation of the problem), a request (a natural language expression of a need), and a query (or system language expression of a need) (p. 811). He then posited, “Now, a relevance (sic) can be seen as a relation between two entities, one from each group: The relevance of a surrogate to a query, or the relevance of a document to a request, or the relevance of the information received by the user to the information need, and so on” (p. 811). We can take for granted, for the purposes of this examination, that Mizzaro’s observations regarding relevance provide a reasonably accurate and accepted summary of IS inquiry and system development work. They do, however, raise some questions for more broadly defined philosophical treatment of relevance. Inherent in his set of clusters (particularly for the first, object-based, group) is the assumption that relevance applies primarily to verbal communication. Further, the assumption is that this communication is formal and structured, that is, it can be shaped and presented in the form of a document. Granted, “document” can be an encompassing idea, but a formal structure inheres in it, even if it is not intended to be limited to a physical artifact that would satisfy a popular notion of what a document is. An assumption that is evident with regard to the second cluster is that humans initiate a process whereby information is sought and located. Further, the two clusters combined (as Mizzaro did to define relevance) suggest a structured human action that entails the making of specific kinds of judgments about objects by people. This model is not particularly problematic (on the face of it) as far as it goes, but it does not go far enough. There are information-related human actions that do not fit so neatly into the clusters, much less into the individual elements of the clusters. This very brief bit of background serves to demonstrate some of the complications one faces when examining relevance. There is no way that a paper of this length can possibly address all definitions, uses, and implications of the word relevance; what is presented here is a selection of some ways of thinking about relevance. One point needs to be made immediately: whether stated or not, relevance judgments are fundamentally construed