“significance,” and “intelligibility” (Sein, Seiendheit, Anwesen, Bedeutsamkeit, Verständlichkeit) will be used interchangeably to refer to the same thing—namely, the “realness” of things in the way Heidegger the phenomenologist understands that heuristic term. For him things are real to the extent that they are meaningfully present (anwesend) to human beings. (See chapter 2: Heidegger’s interpretation of Metaphysics IX 10.) Even though this position—being = realness = meaningfulness—is Heidegger’s own, it may not make all Heideggerians happy. But at least it will obviate the hair-pulling confusion caused by Heidegger’s extraordinary carelessness in his use of the word Sein.

But this phenomenological interpretation of Sein as Anwesen is only the first step. The single issue that drove Heidegger’s work was not being-as-meaningful-presence but rather the source or origin of such meaningful presence—what he called die Herkunft von Anwesen. He called that source the clearing (die Lichtung), or more precisely, the thrown-open or appropriated clearing (die ereignete Lichtung). By contrast, many Heideggerians think that “being itself (das Sein selbst) is “the thing itself” of Heidegger’s philosophy. However, as Heidegger uses that phrase in its primary and proper sense, “being itself” is not any kind of Sein at all. It is not even a phenomenon, much less the Final Phenomenon, the “Super-Sein” that it has morphed into in the secondary literature. “Being itself” or “being as such” is a way of saying “the essence of being,” and all three of those terms are simply formal indications and heuristic stand-ins that point toward the sought-for answer to Heidegger’s question—namely, whatever will turn out to be the “essence” of being, that which accounts for and is the source or origin of meaningful presence at all. And that turns out to be the appropriated clearing, or in shorthand, appropriation (Ereignis)—which is simply the later Heidegger’s re-inscription of what he had earlier called “thrownness” (Geworfenheit) or “thrown-openness” (der geworfener Entwurf). Metaphorically speaking, as thrown-open (i.e., appropriated), human being is the “open space” or clearing within which the meaningful presence of things can occur. (The previous sentence is Heidegger’s philosophy in a nutshell.) In Heidegger’s lexicon the following terms (and there are yet others) are simply different names for the same phenomenon:

Thomas Sheehan - Making Sense of Heidegger