Russell’s paper of 1923 on vagueness raised many of the issues central to subsequent debate. Its effects, however, were delayed. Nothing of significance, and little of insignificance, was published on vagueness between Russell’s work and that of Max Black in 1937.1The latter provoked several responses, and the topic has remained alive, if not always kicking, ever since. Although chance doubtless plays as great a role in the history of philosophy as in the history of everything else, it is not fanciful to suppose that the time was riper for vagueness in 1937 than in 1923. When Russell wrote, philosophy was concerned with language primarily as the medium of science. That could include a wide range of uses, from reporting observed data to formulating mathematical theories about unobservable entities. But it encouraged the use of ‘vague’ as a dustbin category, into which one dumped any failure to meet the ideal of precision, without prying too closely. To vary the metaphor, vagueness was the noise through which a signal had to be discerned. By 1937, philosophers had begun to find ordinary language interesting in its own right. The irreducible variety of its uses was taken to be one of its chief characteristics, and the indiscriminate assimilation of one kind of use to another diagnosed as the origin of many philosophical puzzles. Scientific uses of language were losing their privileged status; for most other uses, the ideal of precision looked irrelevant or damaging. Vagueness is a precondition of the flexibility of ordinary language. This thought converged with an older pragmatist

idea, that too much precision is a bad thing even in scientific language, restricting its adaptability to new evidence.