Add to ORKGThe aim of this paper is to focus on certain characterizations of “I think” and the “transcendental subject” in an attempt to verify a connection with certain metaphysical characterizations of the thinking subject that Kant introduced in the critical period. Most importantly, two distinct meanings of “I think” need be distinguished: (1) in the Transcendental Deduction “I think” is the act of apperception; (2) in the Transcendental Deduction and in the section of Paralogisms “I think” is taken in its representational nature. It proves helpful to interpret the “transcendental subject” in formal terms as a concept that, mutatis mutandis, has the same function of the concept of the “transcendental object.