Logic as a Formal Method

The aim of this article is to present, in outline, a representative selection of the ways in which formal logic has been of service to computer science. Logic offers so many possibilities of application, and there are so many diverse groups of researchers developing logic-based applications, that it will be impossible in the space available to do justice to the whole field. Indeed it will be impossible even to mention everything that is going on, let alone say anything about it. Therefore I confine myself to a few areas which I believe, taken together, give a fair impression of the promise that formal logic holds as a tool for computer scientists. I assume in this article that the reader has a working knowledge of the classical Propositional and Predicate Calculi: a lightning sketch of these systems can be found in my article ‘Classical Logic: a Crash Course for Beginners’ which appears earlier in this issue; for more details, the reader is urged to consult a textbook such as my Logic for Information Technology (Wiley, 1990).