The term “pre-Socratics” has become a fixed component of categorizations in the history of philosophy. We seem to take it as a matter of course that it not only has chronological significance, but is also factually justified as a designation for a particular way of doing philosophy. This view has relatively young roots. It is true that even in antiquity the idea that Socrates marked a departure in the development of (Greek) philosophy was familiar,1 but doxographers were always more interested in the substantive differences between various doctrines than in their temporal order. This way of looking at things, which one might call morphological, was initially adopted within modern histories of philosophy as well.2 Only in the wake of Kant’s critical philosophy did a genetic perspective begin to take hold, one that in various guises remains definitive to this day. It initially took the model of organic nature as its guide, and developed as a discipline through its study; that is, it attempted to identify historical epochs by pointing out phases of growth, maturity, and decay. In his Berlin lectures on the history of philosophy from 1812 (and later),3 Friedrich Schleiermacher understood the “Hellenistic way of thinking” in this new spirit as an “organic” whole and distinguished an initial period of isolated and partial philosophical forms from the period of complete individual designs that begins with Socrates.4 It made sense to call the first period “pre-Socratic” with reference to its goal since it seemed not to admit a unified designation on the basis of the qualities characterizing it, and indeed that is what frequently occurred.5 But this term probably became known to the general public only through Heinrich Ritter’s History of the Philosophy of Antiquity of 1829, which adopted and elaborated upon Schleiermacher’s classification.6 It soon became established and still today seems to be indispensable, although its original factual motivation has long been disputed. It was Nietzsche, before all others, who liberated the pre-Socratics from their assigned role as imperfect predecessors of the classical period of Greek philosophy that begins with Socrates by recognizing their thought as an independent way of doing philosophy of a particular kind. Breaking up the dominant scheme of historical assessment had an equally provocative and stimulating effect on subsequent research into the thinkers who were now emphatically called “pre-Socratic.” It is not so long ago that such diverse philosophers as Heidegger and Popper considered the “early” thought of that epoch as a model from which the philosophy of the present could gain strength for its renewal.7