Peripatetic school, was catalogued with those treatises that ever since have borne the name μετὰ τὰ φυσικά - which are writings that both do and do not belong to the φυσικά. The sentence we just read comes from chapter three of the treatise now called Book I (IV) of the Metaphysics, and the information it provides about φύσις is identical with the guiding principle put forth in Physics, Book B, chapter one, which we have just interpreted: φύσις is one kind of οὐσία. But this same treatise of the Metaphysics, in its first chapter, says exactly the opposite: οὐσία (the being of beings as such in totality) is φύσις τις. something like φύσις. But Aristotle is far from intending to say that the essence of being in general is, properly speaking, of the same kind as the φύσις which, a little later, he explicitly characterizes as only one branch of being [370 {GA 9 300}] among others. Rather, this barely adequately expressed assertion that οὐσία is φύσις τις is an echo of the great beginning of Greek philosophy, the first beginning of Western philosophy. In this beginning being was thought as φύσις, such that the φύσις that Aristotle conceptualized can be only a late derivative of originary φύσις. And a much weaker, much harder-to-hear echo of the original φύσις that was projected as the being of beings, is still left for us when we speak of the "nature" of things, the nature of the "state," and the "nature" of the human being, by which we do not mean the natural "foundations" (thought of as physical, chemical, or biological) but rather the pure and simple being and essence of those beings.

But how should we think φύσις in the way it was originally thought? Are there still traces of its projection in the fragments of the original thinkers? In fact there are, and not just traces, for everything they said that we can still understand speaks only of φύσις, provided we have the right ear for it. The indirect witness thereof is the nonessence that is the historiographical interpretation of original Greek thinking as a "philosophy of nature" in the sense of a "primitive" "chemistry," an interpretation that has been prevalent for some time now. But let us leave this nonessence to its own ruin.

In conclusion let us give thought to the saying of a thinker from those beginnings, one who speaks directly of φύσις and who means by it (cf. Fragment 1) the being of beings as such as a whole. Fragment 123 of Heraclitus (taken from Porphyry) says: φύσις κρύπτεσθαι φιλεῖ, "Being loves to hide itself." What does this mean? It has been suggested, and still is suggested, that this fragment means being is difficult to get at and requires great efforts to be brought out of its hiding place and, as it were, purged of its self-hiding. But what is needed is precisely the opposite. Self-hiding belongs to the predilection [Vor-liebe] of being; i.e., it belongs to that wherein being has secured its essence. And the essence of being is to


Martin Heidegger (GA 9) On the Essence and Concept of Φύσις in Aristotle's Physics B, I - Pathmarks