 Incommensurability between values must be distinguished from the kind of incommensurability associated with Paul Feyerabend (1978, 1981, 1993) and Thomas Kuhn (1977, 1983, 1996) in epistemology and the philosophy of science. Feyerabend and Kuhn were concerned with incommensurability between rival theories or paradigms — that is, the inability to express or comprehend one conceptual scheme, such as Aristotelian physics, in terms of another, such as Newtonian physics.