自我概念無疑地是康德理論哲學當中最值得探討的概念，它一方面是幫助康德建立其先驗認知理論的功臣，另一方面又是造成形上學幻象的元凶。然而，關於自我所扮演的這兩種截然相反的角色，它們內在的統一性仍處於極度的模糊之中，甚至顯得是難以成立的，因為康德否定了自我可以當作思維實體來認識，但是自我又不是完全的「無」，因為康德仍把它視為知識的最高條件。這種張力的存在事實上源自於康德從未直接討論「什麼是自我？」的問題，並提出一個正面的自我理論以說明自我在其哲學架構當中的存有論地位。因此，向康德追問：「自我指涉了什麼？」、「自我是一種什麼樣的存有者？」、「人們應該怎麼理解『自我』這個表達？」將是有意義且無可避免的。為了釐清這個問題，在本文當中我將首先梳理五種既有的主流詮釋，探討它們各自的得失。而最後我將嘗試指出，從自我概念被主流詮釋所忽略的範導機能當中，我們將能夠發展出一套更加理想、與康德的整個體系更加相容的自我論。

Kant's concept of the I is undoubtedly most worth exploring among his theoretical philosophy. On the one hand, it is the foundation stone that helps Kant to build his transcendental cognitive theory, on the other hand, Kant takes it for the root that causes the illusion of metaphysics. However, the inner unity of these two diametrically opposite roles played by the I is still in extreme vagueness, in fact, seems to be untenable, because Kant denies the I as a thinking substance, but nevertheless it is not ＂nothing＂ in an absolute sense, since Kant still regard it as the highest condition of knowledge. This tension stems from the fact that Kant never directly deals with the Question: ＂What is the I?＂, and thus proposes a positive theory of the I to explain its ontological status. In order to clarify this issue, in this article I will firstly survey the five modes of interpretation, to pick out their pros and cons respectively. Finally, I will try to point out that the regulative interpretation, which is at length ignored, is the only ideal mode that can give us a positive theory of the I entirely in conformity with Kant's cognitive theory.