The concept of

Abstract

This article presents a theoretical investigation of the concept of 'subject' or 'subject matter' in library and information science. Most conceptions of 'subject' in the literature are not explicit but implicit. Various indexing and classification theories. including automatic indexing and citation indexing, have their own more or less implicit concepts of subject. This fact puts the emphasis on making the implicit theories of 'subject matter' explicit as the lirst step. A very close connection exists between what subjects are. and how we are to know them. Those researchersw ho place the subjects in the minds of the users have a conception of'subject' different to that possessed by those who regard the subject as a fixed property of the documents. The key to the definition of the concept of 'subject' lies in the epistemological investigation of how we are going to know what we need to know about documents in order to describe them in a way which facilitates information retrieval. The second step therefore is an analysis ol the implicit epistemological conceptions in the major existing conceptions of 'subject'. The different conceptions of 'subject' can therefore be classified into epistemological positions. e.g. 'subjective idealism' (or the empiric/positivistic viewpoint), "objective idealism'(the rationalistic viewpoint),'pragmatism' and 'materialism/realism'. The third and final step is to propose a new theory of subject matter based on an explicit theory of knowledge. In this article this is done from the point of view ol a realistic/materialistic epistemology'. From this standpoint the subject of a document is defined as the epistemologicapl otentials of that document.