In this essay, Heidegger discusses the problem of ἀλήθεια as the interplay of revealing and concealing. Heidegger examines this fragment very closely and interprets it to mean: “From the clearing which never disappears into concealment because always arising from it, how could anyone remain concealed?” The clearing is the open in which entities reveal themselves. The revealing or coming-to-light (Lichten) of entities in the clearing is, at the same time, the concealment of being, as such. The source of the forgottenness of being is not the laxity of being-there; rather, it is intrinsic to being itself. The relationship of being-there to the clearing is nothing else than the clearing itself, insofar as it gathers in and retains being-there. The interplay between the clearing, being-there, and being is Ereignis, which is not only the “wonder of all wonders” addressed throughout Heidegger’s thinking, but also central to the thought of Heraclitus. They both try to think the mystery of being in an attunement of openness, reservedness, and free surrender.
As Heraclitus says in fragment 123, self-revealment, or φύσις, needs concealment in order to come to presence as unconcealment. This self-revealing concealment of being in the clearing is the common denominator of all the grounding words and names that characterize Heraclitean thought. The movements of self-revealing and self-concealing form one (ἕν) identical process. In this process, the light and the dark complement each other and are in harmony (harmonie). Heraclitus describes the harmony of contraries also as discord or strife (πόλεμος) between the positive and the negative. It is a process in which the opposites are meshed into a single pattern of joining. Fire (πῦρ) gathers its force together (“λόγος”) into the process of the coming to presence of being as ornament (κόσμος). In the clearing of the world, being “gifts” itself as destiny and withholds itself in concealment. The movement of concealment and revealment is the coming to pass of ἀλήθεια. In the multiplicity of different names, Heraclitus thinks the fullness of what is the same: the coming into its own, sheltering, and preserving of the truth of being.
Vorträge und Aufsätze (GA 7)