康德晚年对第四问的探讨基本是一种综合性、概括性和总结性的探讨。尤其对其认识论和道德哲学来说是这样，他将认识论和道德哲学放到一个更广阔的范畴中来了，并在此基础上做出了重要补充：一是联系历史政治对人性的探讨（道德哲学的延伸）；二是联系宗教对人性的探讨（回答第三问，但将两问结合）；三是从经验观察到对人性的直接探讨（如实用人类学）。“人应当是什么”或者“人将会是什么”还是要受到“人实际是什么”的限制的，这意味着我们要看到人不仅有理性，还有非理性。全面地看待“人是什么”，还应该深入分析人的欲望、非道德情感、各种意志（而不仅仅是道德意志）以及信仰——不仅是在单纯理性的范围内，还有对历史和现实的宗教形态的分析。对“人的有限性”的认识不仅要看到认知的局限性，还应意识到道德和审美的有限性。虽然康德并没有像他在回答前三问中那样，特别地提出一个根本的新理论和原则，但第四问的提出依然有重要价值：不仅为康德，也为我们提供了一个新的视角用以审视其全部的四问，甚至观察全部的康德哲学体系。

康德, 人学, 形而上学, 道德, 康德之问

Kant’s exploration of the Fourth Question in his later years was essentially comprehensive,general, and summary in nature, especially in terms of his epistemology and moral philosophy. He placed his epistemology and moral philosophy within a broader scope. At the same time, there were important additions. “What man ought to be” or “what man will be” is still constrained by “what man actually is”, so it is necessary to recognize that humans possess not only rationality but also irrationality. The recognition of “human finitude” should not only see the finitude of cognition but also the finitude of morality and aesthetics. Although Kant did not propose a fundamental new theory or additional new principles specifically in answering the Fourth Question as he did in the first three, the formulation of the Fourth Question still holds significant value. Not only can we now observe all four of Kant’s questions through the lens of the Fourth Question, but we can also observe the entirety of Kantian philosophy in this way.

Kant, anthropology, metaphysics, morality, Kant’s Questions