A Non-Classical Logic for Information Retrieval

This paper is to be seen as describing a new theoretical framework for investigating information retrieval. For some years now, I have felt the need to describe such a framework. It is especially important if one wants to develop information retrieval beyond the mere keyword approach. In the closing pages of my earlier book on the subject I said the following: “It has never been assumed that a retrieval system should attempt to understand” the content of a document. Most Information Retrieval systems at the moment merely aim at a bibliographic search. Documents are deemed to be relevant on the basis of a superficial description. I do not suggest that it is going to be a simple matter to program a computer to understand documents. What is suggested is that some attempt should be made to construct something like a naive model, using more than just keywords, of the content of each document in the system. The more sophisticated question-answering systems do something very similar. They have a model of their universe of discourse and can answer questions about it, and can incorporate new facts and rules as they become available (van Rijsbergen, 1979).