The essay shows how Heidegger's understanding of physis in Aristotle lays the foundation for his understanding of Ereignis. The essay draws on Heidegger's lecture courses, published and unpublished, particularly "On the Being and Conception of Physis." After introductory remarks on how Heidegger reads Aristotle "phenomenologically" in general, the essay focuses on how Heidegger reads physis as a mode of Being (ousia) by reading kinesis as a mode of Being, specifically as energeia ateles (incomplete Being). But energeia ateles is characterized by (...) Heidegger as Wiederholung (retrieve of possibility) and as Eignung (appropriation of dynamis for appearance). On the basis of that crucial reading of physis, the essay goes on to show how physis-as-dynamis is the foundation for Ereignis in Sein und Zeit through the radical transformation of Wiederholung in natural beings into resolve in Dasein. (shrink)