重思康德对自由与道德法则的演绎——以《道德形而上学奠基》与《实践理性批判》为中心

Rethinking Kant’s Deduction of Freedom and the Moral Law: Focusing on the Groundwork of the Metaphysics of Morals and the Critique of Practical Reason

摘要: 康德在《道德形而上学的奠基》中宣称对道德最高原则的演绎无可指摘，但在《实践理性批判》中却否认道德法则的可演绎性，转而将道德法则作为“理性的事实”为自由提供基础。这一表面上的立场转变被学界解读为“巨大颠倒”，意味着康德承认自由演绎的失败并转向新的论证路径。然而，深入分析表明，前一著作的核心是自由的演绎，而道德法则的不可演绎性构成后一著作论证的起点。通过重构两文本核心论证，结合历史源流、著作目标、论证结构与文本类型的考察，可以表明康德在自由与道德法则问题上的根本立场具有内在一致性。这一结论不仅澄清了康德伦理学的发展脉络，也为理解其实践哲学提供了范式。

Abstract: In the Groundwork of the Metaphysics of Morals, Kant claims that the deduction of the supreme principle of morality is irreproachable. Yet, in the Critique of Practical Reason, he denies the possibility of deducing the moral law, treating it instead as a “fact of reason” that grounds freedom. This apparent shift in position has been interpreted by scholars as a “great reversal”, suggesting that Kant acknowledged the failure of his earlier deduction and adopted a new line of argument. However, a closer analysis reveals that the core of the former work lies in the deduction of freedom, while the non-deducibility of the moral law constitutes the starting point of the latter. By reconstructing the core arguments of both texts and examining their historical context, aims, argumentative structures, and textual genres, it becomes evident that Kant’s fundamental stance on freedom and the moral law maintains an inherent coherence. This conclusion not only clarifies the development of Kantian ethics but also provides a framework for understanding his practical philosophy.