康德的「根本惡」說——兼與孟子的性善說相比較

Kant’s Theory of the “Radical Evil” as Compared with Mencius’ Theory of Human Nature

秦家懿教授在其〈中國倫理學與康德〉一文中泛論中國各家底倫理思想之餘，特地指出儒家與康德底倫理思想在基本態度上的一項對比，此即儒家（她以王陽明作為代表）底道德樂觀主義與康德對人性的不信任。文中寫道：對於康德而言，人在本性上是惡的，也就是說，人意識到道德法則，但卻經常背離它。康德並不因此而反對自然的愛好，而是表示：這些愛好需要順服，以與理性相調和。道德的探求基本上是一場奮鬥，人類將藉此持續地使其感性的本性服從道德法則（定言令式），以便更妥善地決定自己向最高善而趨。對於王陽明而言，人即使具有一種向惡的性癖，在本性上仍是善的。道德的探求成為一個淨化底過程，以恢復人原有的善性為目標。這需要抉擇和毅力， 而非強力。此處所提到的康德底人性論主要是就其《單在理性界限內的宗教》一書（以下簡稱《宗教》）而言，尤其是就該書底第一卷而言。康德在此提出了「根本惡」(das radikale Bose)底概念，以說明道德之惡在人性中的根源。雖然秦教授在此文中並未進一步探討和比較儒家與康德底人性論，但是她這段話卻很容易使人產生一個印象，以為康德主張性惡論，與孟子正相對反，因為王陽明底心性論顯然承自孟子。依筆者之見，這個印象很有問題，不但妨礙我們對康德倫理學的正確理解，也無助於我們了解和評估孟子底性善論。為了澄清這個問題，筆者在本文中將探討康德底「根本惡」說，並闡述其中所涉及的問題。

After establishing his ethical system in Groundwork of the Metaphysic of Morals and Critique of Practical Reason, Kant also advances the theory of the “radical evil” in Religion within the Limits of Reason Alone, with the intention of expounding the anthropological origin of the morally evil, and then of building up a theory of moral discipline. With regards to this, some scholars, for example, Prof. Julia Ching, look upon Kant as an advocate of the thesis that man is evil by nature as opposed to Mencius, whose belief in man's original goodness represents the dominant thinking of Confucianism. In my opinion, this is a superficial viewpoint. In order to dispute this thesis, I fully analyse the philosophical implications of the theory of the “radical evil” and its place in Kant's ethical system, with a view to clarifying common misinterpretations. While Kant regards the “radical evil” as “natural” or “inborn, ” he also holds man responsible for its origin in order to reconcile the apparent contradiction in his theory. My analysis tries to explain this issue. Further, I stress that the concept of “hsing” (性) in Mencius is not equivalent to that of “nature” in Western philosophy, because the two concepts belong to different levels of discussion. Kant views the “radical evil in human nature” on the empirical level of “practical anthropology, ” whereas Mencius advances the theory that man is good by nature on the non-empirical level of “metaphysic of morals. ” Not only are the two theories by no means contradictory, but they are complementary to each other. Moreover, even on the level of “practical anthropology, ” Kant is not an advocate of the thesis that man is evil by nature, since he is convinced of the “original predisposition to good in human nature. ”