Conceptual Spaces as Philosophers' Tools

This paper gives an overview of the main philosophical applications to which conceptual spaces have been put. In particular, we show how they can be used to (i) resolve in a uniform way the so-called paradoxes of identity, which are basically problems concerning material constitution and change over time; (ii) answer one of the core questions in the debate concerning vagueness, to wit, the question of what a borderline case is, for instance, what makes some items neither clearly green nor clearly not green but borderline green; and, building on this answer, give a philosophically coherent account of the graded membership relation that is at the heart of fuzzy set theory; and (iii) provide a novel analysis of the concept of knowledge, which answers in a conservative way questions recently raised about the relationship between knowledge (or knowledge ascriptions) and the practical interests of putative knowers.