Conceptual Comparison and Conceptual Innovation

Abstract

The guiding idea of this paper is that discussions of comparisons of concepts across theories (individuals, historical periods, cultures) and the introduction of new concepts must be based on an account of how the content of concepts is determined. I will sketch a theory of concepts based on the work of Wilfrid Sellars, although with several modifications.¹ Then I will illustrate the application of this theory in two cases. First, I will compare the concepts of earth, water, and air as they appear in Aristotelian physics and in Galileo. Second, I will consider the concept of an isotope, an example of a new concept whose introduction is fairly well localized in the history of chemistry. There are two general conclusions that I want to draw from this discussion. First, a Sellarsian approach provides a specific set of tools for comparing concepts and introducing new concepts. Second, major conceptual change can take place while maintaining a great deal of continuity with existing conceptual resources.

One central theme of Sellars’ theory of concepts is that concepts occur only as members of systems of interrelated concepts. At least part of every concept’s content is determined by implications which hold between that concept and other concepts in the system. While holistic, this view should be read as a local holism. It does not require that all concepts link together into a single massive conceptual scheme. Rather, each of us deploys many different conceptual systems that have a variety of relations to each other. I have concepts that I use for thinking about poker, and some of these concepts have close ties to concepts that I use for thinking about other card games, and perhaps other games; but they have little connection with concepts that I use for thinking about carpentry or plate tectonics. I also have two conceptual schemes for thinking about space and time—one from everyday experience and one from relativity theory. There are close and complex relations among the concepts in the two schemes, and there are good reasons for describing both as systems of space and time concepts.² Still, they can be treated as distinct conceptual schemes and I can shift from one to the other without confusing them.