David J. Stump is a philosopher of science at the University of San Francisco, USA. He is co-editor, with Peter Galison, of The Disunity of Science, and is author of numerous journal articles on the history and philosophy of science.

In this book, David Stump traces alternative conceptions of the a priori in the philosophy of science and defends a unique position in the current debates over conceptual change and the constitutive elements in science. Stump emphasizes the unique epistemological status of the constitutive elements of scientific theories, constitutive elements being the necessary preconditions that must be assumed in order to conduct a particular scientific inquiry. These constitutive elements, such as logic, mathematics, and even some fundamental laws of nature, were once taken to be a priori knowledge but can change, thus leading to a dynamic or relative a priori. Stump critically examines developments in thinking about constitutive elements in science as a priori knowledge, from Kant's fixed and absolute a priori to Quine's holistic empiricism. By examining the relationship between conceptual change and the epistemological status of constitutive elements in science, Stump puts forward an argument that scientific revolutions can be explained and relativism can be avoided without resorting to universals or absolutes.

1. Introduction: Theories of the Constitutive Elements in Science 2. Reinventing Geometry as a Formal Science 3. Poincaré's Conventionalisms 4. The Logical Empiricist or Positivist Engagement with A Priori Knowledge: Schlick, Reichenbach, Carnap, and Ayer 5. Alternative Conceptions of the A Priori: Cassirer, Lewis, and Pap 6. The Status of Newton's Laws 7. Conceptual Change and the Constitutive Elements of Science: Kuhn, Friedman and Hacking 8. On the Role of Mathematics in Physical Theory 9. Epilogue: A Pragmatic Theory of the Constitutive Elements in Science