Abstract
Since Critique of the Pure Reason was published in 1871, the concept of thing in itself has been always a controversial issue. Because in Kant’s System, causal relation is valid only for appearances and can not be applied outside the experiences, so it is a conflict to assume an object in itself as a cause that exists outside the appearances or experiences and results various representations in our minds. However, Kant seems to claim that this affection is the outset of cognizing activities of the mind. Jacobi once criticized the presumption of thing in itself: without the presupposition I could not enter into the system, but with it I could not stay within it. This problem still exists nowadays, and the interpretations are separated into two ways: metaphysical and methodological. However, I will argue that the two interpretations are both incorrect. They only grasp the meaning of thing in itself partially and thus can not interpret it without difficulties. In the essay, I will give another interpretation which is different from the two mentioned, and then differentiate various meanings of thing in itself and transcendental idealism according to different contexts in Critique. I will explain the meanings of thing in itself and transcendental idealism in Kant’s critical inquiry, in his Copernican turn, in the doctrine of time and space, in his theory of categories and schemata, and in transcendental ideas and antinomies. The concepts of thing in itself in these contexts are all distinctive. For Kant, transcendental idealism, thing in itself or appearances are not terms that have only one certain and peculiar meaning. Kant does not create these terms, which have their ordinary meanings, but only convey by them what he wants to say in different contexts. In the end of the essay, I will conclude that transcendental idealism should be considered in two senses, and the concept of thing in itself has five distinctive meanings in different contexts.