PRINCIPLE OF IDENTITY, THE (Der Satz   der Identität  ). 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. (Schalow & Denker  , p. 231)