The point of departure for our study of the mystical element in Heidegger’s thought is the course of lectures which Heidegger gave at Freiburg in 1955-56 and which he published under the title The Principle of Ground ([Der Satz vom Grund->GA10]). The text consists of a series of thirteen course lectures and a concluding address on the subject of this famous principle of Leibniz. “nothing is without reason” (nihil est sine ratione). These lectures, which are a lucid and penetrating exposition of Heidegger’s view of the nature of ground and reason, are not often accorded the attention in the literature on Heidegger that they merit. But as our discussion of Versényi’s critique of Heidegger already suggests, [SG->GA10] is a work of special pertinence to the present study, and this for two reasons.
(1) In the first place, Heidegger’s critique of the Principle of Ground is for him not merely a critique of Leibniz. Rather, Leibniz’s principle is a touchstone of the entire Western metaphysical tradition, i.e., of the history of philosophy and reason in the West. For Leibniz’s principle is not Leibniz’s principle ([SG, 47-8->GA10]), but an expression of the mission or destiny (Geschick) of Being in the West. Being speaks in and through Leibniz. What comes to a head in Leibniz’s thought has been there from the beginning in Western philosophy and is with us still today, viz., the demand that a rationale or a ground be brought forth for whatever is held to be “true.”
The importance of [SG->GA10] is that it contains Heidegger’s analysis of this most basic principle of metaphysics. After a close examination of just what this principle meant in Leibniz’s own philosophy. Heidegger moves forward, with a great show of virtuosity. to demonstrate how this principle exerts a decisive influence on Kant and. beyond Kant. on the twentieth century, the age of the atom. our own “time of need.” As Löwith remarks about [SG->GA10]:
. . . in the lecture Der Satz vom Grund. the discussion of the traditional principle of thought is not broken into by chance and incidentally by a dramatic allusion to the historical situation. but rather it is essentially inspired by this allusion. and indeed in such a way that the reference to the need of the time the established danger of the atom bomb must explain the abyssal (abgründige) danger of thinking according to the authority of the Principle of Ground (according to which every being must have a ground in another and ultimately in a highest being). (Löw. 110)
From Leibniz’s formulation of the Principle of Ground Heidegger also moves backwards to the Greek logos, of which ratio and Grund are the translations. In the Greek logos Heidegger will find a more primal sense of “ground.” [SG->GA10] then orchestrates all of the important themes in Heidegger’s interpretation of the history of Western thought, and allows him to develop in a penetrating way his critique of philosophical reason.
(2) The second reason we attach such great importance to [SG->GA10] lies in the fact that in no other work does Heidegger so openly make use of the mystical tradition. The pivotal lecture in this book ([Lecture V, SG, 63 ff.->GA10]) is an “elucidation” (Erläterung) not of Hölderlin but of the verse from the mystical poet Angelus Silesius, “The Rose Is Without Why.” By means of this verse, Heidegger will show us the necessity of a “leap” (Satz) out of the Principle of Ground as it has been understood by metaphysics into a new and deeper understanding of it. This leap is a leap away from the metaphysician’s understanding of “why” and “because,” represented by Leibniz, towards the mystic’s understanding of it, represented by Angelus Silesius. It is in this workalong with Gelassenheit that Versényi claims Heidegger’s thought enters into a third and decisive stage which disrupts the balance or “dialectic of correspondence” between Being and Dasein of which he and Löwith speak. In this work, Versényi claims, the capacity of Dasein for a dynamic response to Being is destroyed. Dasein becomes a humble, passive suppliant waiting upon Being’s next inscrutable move. Thus a close study of this text is essential if we are to evaluate this critique of Heidegger’s later and seemingly mystical writings.