Abstract

Touching your mother's foot is incest because all the rest is a matter of degree (or so said Diogenes). That's just one expression of the puzzle of vagueness. Here's another: the passage of one second cannot mark the transition from being a pupa to being a butterfly--if something is a pupa at one time then in all close instants it remains a pupa; alas, it follows from this, via trivial logic, that there are no butterflies. Or again: it's vague where the Highlands of Scotland begin and end, so, a small step in the direction of London cannot mark the boundary between the Lowlands and the Highlands. But then it follows, via trivial logic, that one is unable to leave the Highlands (even when in London). What's driving these paradoxical arguments seems to be the very vagueness of the terms involved: such terms as 'incest', 'butterfly', 'pupa', 'The Highlands' are all vague and such vagueness seems to make them tolerant to marginal change. The puzzles of vagueness are not only deep (in that they admit of no uncontroversial and entirely satisfactory solution), they are also broad, for vague language is everywhere. In this course, you will be introduced to the various puzzles of vagueness and whether and how we might best address them. We will tackle such as questions as: Does the possibility of vagueness entail that there simply cannot be a logic of natural language? Does it entail that language is governed by inconsistent rules? Or does vagueness require some special or deviant logic? Is vagueness a special species of ignorance? Is the world, in some sense, vague? Is there an uncontroversial definition of vagueness or can we only isolate the phenomenon from within some substantive and controversial conception? What is higher-order vagueness and why is it considered to be such a puzzling phenomenon? Must the truth about vagueness be so strange? In what exact way are vague expressions tolerant?