Scientific pluralism and the plurality of the sciences: Comments on David Hull's Science as a Process

Abstract

Science as a Process is a complex work. David Hull provides us with a brief history of biology from Aristotle to the present, a detailed insider's history of modern systematics, a general theory of the metaphysics of selection processes, an account of how science provides an example of such a process, and an extended defence of this view against the standard objections to evolutionary epistemology. The historical parts, especially the systematics, provides the major source of evidence for the last two. Each of these topics could well have received book length treatment, and most of them do. Thus it is no easy task to decide on which part of this complex to focus. In this paper I shall have most to say about the later, more strictly philosophical parts, and especially Hull's theory of the evolution of science. Let me begin, then, with Hull's main philosophical proposals, leading up to his account of the metaphysics of selection and his assimilation of science to an example of a selection process. An essential preliminary to this, and incidentally one of Hull's most original and important philosophical contributions, is an understanding of his views on general terms. An assumption that has hardly been challenged in the history of philosophy is that whatever the references of general terms may be, they are in some sense general. For many years Hull has championed the view that terms referring to species, and perhaps also larger groups, of organisms domestic pigs, African elephants, flammulated owls, etc. refer not to kinds of thing at all, but to individuals. Specifically, they refer to lineages, to particular chunks of the total genealogy of life on Earth. Thus to refer to something as a pig, say, is not to say what kind of a thing it is, but rather to say what larger more enduring thing it is a part of, in this case the species Sus domesticus. Species, according to Hull are not kinds, but individuals.1 Thus however piglike the creatures we might imagine discovering on Alpha Centauri, even though