Exemplars and Scientific Change

Philosophers have distinguished a metaphysical category which they term "historical entities" or "continuants". Such particulars are spatiotemporally localized and develop continuously through time while retaining internal cohesiveness. Species, social groups and conceptual systems can be profitably treated as historical entities. No damage is done to preanalytic intuitions in treating social groups as historical entities; both biological species and conceptual systems can be construed as historical entities only by modifying the ordinary way of viewing both. However, if species and conceptual systems are to "evolve", then they must be treated as historical entities. The type specimen method, which is used by systematists to individuate and name biological taxa, is set out and then extended to apply to scientific communities as social groups and conceptual systems.