TOWARDS A THEORY OF TOPICS

Abstract This paper attempts to address a few of the theoretical and practical problems surrounding the exposition of a topic by a computer program. A topic is defined as a system of concepts which must be formalised before it can be expounded. The formalisation of a topic poses representational problems of logical adequacy, but the underlying structure is that of a cluster of concepts which appear in each other's pre- and postconditions of application. A text, on the other hand, is a sequence of inscriptions, and therefore a linear formalisation of a conceptual system which may not itself be linear. This poses problems of control, since one has to decide where to begin and what to explicate in terms of what. The resultant structure of a text can be viewed as a pragmatic realisation of the structure of its topics, an unfolding of the conceptual system which employs a number of expository mechanisms to make the propositional content of the text acceptable to the epistemology of the reader. It is suggested that some of these mechanisms can be related to certain logic programming constructs in a simple way, and that such languages might provide useful tools for exploring the possibilities of computer aided exposition.