ON PURITY OF MORAL KNOWLEDGE: ROSS’S OBJECTION TO KANT

Abstract

This paper examines David Ross’s objection to the “purity” of moral knowledge in Kant’s ethics, as presented in his commentary on the Groundwork of the Metaphysics of Morals. Ross, while accepting the a priori status of moral law, argues that it is not pure, drawing an analogy to the category of causality in natural science, which he considers a priori but empirically dependent. This study aims to clarify Kant’s position on the purity of moral law and to assess the validity of Ross’s analogy. The paper applies conceptual and textual analysis of Kant’s Groundwork and Critique of Practical Reason, focusing on the distinction between pure and impure a priori judgments, the noumenal nature of the moral agent, and Kant’s view on moral law as a “fact of pure reason.” The analysis reveals that Kant’s moral law, as embodied in the Categorical Imperative, is grounded in pure (non-empirical) causality and freedom, thereby leaving no room for empirical intrusion. The conclusion compares moral law to pure a priori propositions in mathematics, suggesting that moral judgments can share the same independence from experience. The findings indicate that Ross’s “impurity” objection fails and that Kant’s moral law retains its status as a pure...