本文旨在釐清牟宗三與海德格詮釋對康德「有限性」概念之詮釋，借此建立三者的溝通基礎。牟跟海一樣，認為康德對存有論的論述並不完備，需要補充；海德格認為康德哲學應下開「基礎存有論」，發展「此在形上學」。牟宗三則認為，應該發展「道德的形上學」；牟重視現象與物自身的區分，因其關乎認知與道德、感性與超感性領域之分際，並認為道德之超越性是人「可無限」的關鍵；海德格則意圖改變感性、知性的優次地位，強調感性、處境和時間性，否定人之無限性。基於以上異同，本文進一步申述兩者對康德哲學的改造與後續發展，設想他們之間的批評和回應，並評論兩者在何種意義下，更能承先啟後。

This paper aims at laying the foundation of a discourse between Mou and Heidegger’s philosophy through their interpretations of Kant’s concept of finitude. Mou tried wholeheartedly to internalize Kantian philosophy in the interest of establishing the new Chinese philosophy which takes the moral subject as the foundation of the system. The key to success lies in the interpretative works of arguing the transcendental character of man with the following premise: man is finite but can be infinite; Heidegger, as a phenomenologist, claims that the concept of finitude is the fundamental spirit and implicit premise of the whole Kantian philosophy. He upholds the priority of sensibility and concludes that human finitude has to be delimited by the situation in terms of time, by which he rejects the infinitude of human existence. By the juxtaposition of their interpretations, we can see how they interpret the concept of finitude, and how they try to internalize and go beyond Kantian philosophy.