In this 1961 lecture, Heidegger shows once again that being is worthy of thought and remains within the purview of human finitude. The topic of the lecture is Immanuel Kant’s famous thesis that being obviously is not a real predicate, but merely the “positing” of a thing with all its predicates. This thesis contains two assertions. The first is a negative one, which denies to being the character of a real predicate. The second is positive and characterizes being as “positing,” as the positioning of a thing qua object over against the knowing subject. In this lecture, Heidegger follows Kant’s episodic elucidations of his thesis about being.
Although it is not a first principle, Kant effects a decisive turn in the history of metaphysics. The question of being takes a double form in metaphysics: (1) What are entities, in general, as entities?; and (2) which entity is the highest and in what way? The onto-theological constitution of metaphysics results from the way the being of entities manifests itself. Being manifests itself as ground. In Kant’s thesis, being is determined as position, that is, a placing and “positioning,” which means to establish a ground. In recognizing that “being” is indefinable objectively as things, but instead is a dynamic that determines their mode of appearance to a finite subject, Kant faintly intimates the difference between being and entities.
Kant says that “is” qua existence is the absolute positing of a thing. Existence is such a simple concept that we can say “nothing” by way of unfolding it. Heidegger remarks that Kant thinks of existence and being in relation to the capacities of our cognitive understanding (Verstand). Our “positing” of a thing as an object is only possible if something is given to “position” or “place” it in relation to our finite subjectivity, i.e., via an act of sensory intuition. Positing has the character of a proposition whereby something is placed before us as something. The “is” of the copula intends the objective unity of apperception. Being and unity belong together. This original synthetic unity of transcendental apperception makes possible the being of entities as the objectivity of objects.
Heidegger points out that Kant never questions his guiding thread that it is possible for being and its modes to be determined from their relation to our cognition. “Being and thinking” is the main title for the interpretation of the being of entities. For Kant, thinking means representational thinking that posits and judges.
In the section on the postulates of empirical thought in general in the Critique of Pure Reason, Kant determines being in its modalities, i.e., being actual and being necessary, as a transcendental predicate. Because being in its modalities is thought of as a predicate, being is still a positing. Thought determines the modalities of being and positing. These determinations are discovered in a reflection (Reflexion). Being is positing; thinking is reflection. Kant thus elucidates the relation between positing and reflection (Reflexion).
Heidegger now asks what the “and” in “being and thinking” means. According to the famous saying of Parmenides, being and thinking are the same or identical. In Greek philosophy, being is that which grants presence. Being appears as presencing. Here, the concealed relation between being and time faintly appears. Thus, it becomes clear that the guiding title of metaphysics, “Being and Thinking,” does not really pose the question of being. For Kant, the belonging together of being and thinking, like the difference between being and entities, remains unthought.