Der Satz der Identität

The Principle of Identity

Heidegger delivered this lecture on 27 June 1957, at the University of Freiburg. It is a careful meditation on the principle of identity that looks back at the essential origin of metaphysics and looks ahead into the domain of technology and nihilism as the end of metaphysics. The principle of identity expresses the highest law of thinking in the formula: A = A. In this formula, the nature of identity remains unthought. With Plato, Heidegger tries to clarify the sense of the relation of identity. A = A does not mean that each self is the same. The relation of identity is a mediation and synthesis. The principle of identity neither asserts that two terms are identical nor names the empty self-identity of each entity. It expresses the mediation in the being of each entity and is therefore not only a principle of thinking but also of being. The mediation of being and thinking finds its completion in the philosophy of the German idealists.

What does the identity of being and thinking mean? Heidegger elucidates this essential relation in an interpretation of the poem of Parmenides. Human beings and being belong together, and have been delivered over to each other. In the age of technology and nihilism, the constellation of human beings and being is dominated by positionality. Ereignis is the abground of the belonging together of human beings and being. In our time this belonging together has lapsed into forgottenness. A return to the origin of the principle of identity may make another beginning in the history of being possible.