Peirce’s concept of science entails that normative judgment in science, about which types of theory or explanation or evidence, etc., are good, must depend on the evidence provided by the experience of inquiring (Chapter 2), a thesis supported by the history of science (Chapter 3). This implies a method, at once empirical and normative, which Peirce’s late sketch of a trio of ’normative sciences’ (aesthetics, ethics, logic) generalizes and rationalizes. Its generalization is supported by Peirce’s expansion of empiricism (Chapter 7), and its rationalization depends on the rediscovery of final causation (Chapter 6). Although sketchy, Peirce’s idea of normative sciences is important; for its plausibility undermines that most pernicious of dichotomies, of fact and value. This chapter explicates Peirce’s idea of normative science, traces its method from Schiller’s aesthetics through Kant’s ethics, and suggests that the rediscovery of final causation corrects what is most problematic in Kant’s metaphysics of morals, viz., its anti-naturalism.