The dictum of Anaximander of Miletus [6-7]

something un-Greek into the content of the whole statement. Here it is in fact so; stepping forth means originating arrival, arriving emergence, self-manifestation, appearance;1 correspondingly, receding means disappearance, withdrawal, going away. So what is the difference between these and coming to be and passing away? We are accustomed to think of coming to be as development, as a sequence of processes in which the earlier ones are always the causes of the following ones, as concatenation, transition, progression, as direction, as from . . . to, out of . . . into; and correspondingly we think of passing away as downfall and annihilation. For the Greeks, what is decisive is not the causal sequence, the coming to be out of and through one another, but purely and simply the stepping-forth, the looming up. Our term for it in short will be appearance. (Cf. below p. 8; need to carefully set aside every relation to later meanings of the word as a technical term, even the relation to the Kantian concept, although Kant does, within certain limits, use “appearance” genuinely and originarily. It is only because “appearance” becomes the counter concept to “thing-in-itself” that we cannot appeal here to Kant.)

Appearance is emergence: not the becoming seen and apprehended of something, but a character of the happening of beings as such. Only subsequently applicable to a being in its becoming perceived and grasped. To appear: to remain in apparentness—or to withdraw from this. To appear: as we say “a new book has appeared” or “the president of the society thanked the appearing guests for making an appearance.” Appearing can be understood only very broadly and originarily, and it oscillates within the meaning of γένεσις—thus not coming to be, but stepping forth. And receding, disappearance, is merely a distinctive mode of appearance and belongs completely to it; for only what has appeared or can appear can also disappear and specifically such that the appearing is retracted.

c) ἐξ ὧν—εἰς ταῦτα—the whence-whither—our
characterization of stepping forth and receding.
Inadequacy of speaking about a “basic matter”

b) The stepping-forth and the receding are to beings not just any random occurrence but are instead precisely essential to the ὄντα. And now both are characterized more closely in a determinate respect. ἐξ ὧν—εἰς ταῦτα; the whence of the coming forth and the whither of the disappearing. And it is said: the whence and the whither of appearance (disappearance)

1 1. Up—forth. γένεσις qua "genesis" only later; in Aristotle only when grasping κίνησις, and even then still primarily in terms of ποίησις, i.e., production—εἶδος.

The Beginning of Western Philosophy (GA 35) by Martin Heidegger