ABSTRACT
The issues that dominated Cambridge philosophy during the 1930s still to a certain extent dominate contemporary philosophy. For it was at that time that the fundamental divide between theorists of formal semantics, such as Russell, and theorists of communication-intention, such as the latter Wittgenstein, first took shape. It is therefore a fairly straightforward exercise to map the thought of a Cambridge philosopher on to current debates. Wittgenstein and Russell are, so to speak, still players to be dealt with. Keynes too was a philosopher involved with later Cambridge thought, and the ideas he penned in letters, manuscripts and lecture notes at that time find a home context in today’s debates in the philosophy of the social sciences. He came to focus on one of the issues which occupied Wittgenstein and Ramsey: they drew attention to the inevitable vagueness of ordinary language and to how this property challenged the analytic project of constructing a fully formalized language based on predicate logic. However, none of these philosophers were bothered by the failure as they came to recognize that vague concepts paradoxically could be more efficient than formalized ones, particularly, as Keynes argued, when analysing complex entities such as social reality. There is today a great deal of work being done on the compatibility of classical logic with vague predicates and on alternative, fuzzy logics. Keynes’s ideas on the role of vague concepts therefore have a contribution to make to this discussion, particularly since few philosophers have pursued the issue within the social sciences.
