The stability of an emergent-appearing thing is thus its “con-stancy,” its ingatheredness (con-) into a stand (Late Latin stare), into its “form”—that is, its intelligible appearance. Here “constancy” is to be understood primarily as steadfastness-in-appearance rather than as permanent presence. Heidegger puts Ständigkeit and ἀλήϑεια together: “The standing [of a thing] is the constancy of [the thing’s] shining.”35
This self-unfolding emergence is the standing-in-ϕύσις of the thing that is present within [that dynamism]—it is the occurrence of the presence [of the thing]: its coming to presence. But that entails two things. The intrinsic unfolding from out of itself—whatever is stable-in-itself—has absolutely no need of anything else [in order to come to a stand as itself]. But at the same time the emergence thanks to which everything has its permanence and enduring, is what is constant in itself.36
After the first meaning of a thing’s “taking a stand” the second meaning that Heidegger retrieves from Ständigkeit as steadfastness is staying power. Having taken a stand within its limits and in its form, a thing “stays around” for a while. In itself steadfastness does not necessarily entail that the thing is permanently present (although it can gain that sense: see below). Rather, steadfastness, as an entity’s being, refers to the staying power whereby a thing holds itself in appearance and “stays there for a while.”37
In this regard Heidegger offers an illuminating interpretation of the Greek adverb ἀεί, which is usually translated as “forever” or “eternally.”38 At Physics 193a21–28 Aristotle starkly contrasts two Greek terms: ἀΐδιον (usually “eternal,” from ἀεί) versus ἀπειράκις (“without limit”: compare ἀ + πέρας, and the Latin translation in-finities). Heidegger argues that in the context of Physics II 1, ἀΐδιον is not to be understood as “persisting, continuing” (das Fortwähren)39 or even “everlasting” in the sense of limitless duration or sempiternity. That would be the meaning of ἀπειράκις (ongoing without limit), which is the very opposite of ἀεί. Rather, ἀΐδιον refers to a thing’s current (jeweilig) presence within its πέρας, but a “presence that is in itself.”40 A thing that is ἀΐδιον is not
35. GA 5: 71.2–3 = 53.12–13: “‘Stehen’ ist (vgl. S. 21) die Ständigkeit des Scheinens.” Ibid., 21.30–31 = 16.15–16: “Das Sein des Seienden kommt in das Ständige seines Scheinens.”
36. GA 73, 1: 85.20–22: “Das Sichentfaltende [sic] Aufgehen aber ist das Hereinstehen von darin Anwesendem—Geschehnis der Anwesenheit—Anwesung.”
37. Verweilen is usually (but a bit too preciously) translated as “to tarry” or “to while.”
38. GA 9: 268.18–270.13 = 205.17–206.32.
39. GA 73, 1: 86.10.
40. GA 73, 1: 86.10. “das In-sich-wesende Anwesen.” Heidegger continues: “die Ewigkeit—das ἐξαίφνης (Dialog Parmenides),” ibid., 86.10–11. He is referring to his interpretation of “eternity” (see immediately below) and to Plato’s Parmenides 156d3, “the instant” or “the moment,” using the nominalized adverb derived from ἄφνω, “suddenly, unawares, in the moment.”