the tripartite meanings of being, the epochal understanding, from Lee Braver's A Thing of This World
Studying the history of metaphysics serves the genealogical purpose of teaching us A3 [Ontological Pluralism: “There are many kinds of eyes. . . . Consequently there are many kinds of ‘truths,’ and consequently there is no truth” (Nietzsche, The Will to Power, 540).]—that our way of experiencing the world is contingent, enabling us to resist its insistence that it is the one and only truth. This multiplicity of epochal releasings, however, also points us toward their point of origin or releasement.Continued
Proper inquiry must be a dialogue in which the  ways of hearing and points of view of ancient thinking are contemplated according to  their essential origin, so that the  call under which  past, present, and future thinking—[A3] each in its own way—all stand, might begin to announce itself.[P. 86, see also p. 61; p. 302; p. 436]Whereas the switchover between the modes of Being of tools and objects in Being and Time pointed to their source in Dasein and society, now the various epochal understandings of Being point to what is beyond them, to their source in appropriation (Ereignis) or destiny (Geschick), to Being itself. “What is peculiar to  Being, that to which Being belongs and in which it remains retained, shows itself in  the It gives and its giving as sending. . . . When we explicitly think about  Being, the matter itself leads us in a certain sense away from  Being, and we think  the destiny that gives Being as a gift” (P. 10, bracketed comments added). When we think of epochal understandings of Being and realize just how deep they go and how dependent we are on them, we realize that we couldn’t have created them (ICS, R5), and we wonder how they could have changed. We cannot accept any intra-epochal explanations—what Heidegger calls onto-theological answers such as that God or man altered them—since these answers themselves only make sense within a particular epochal understanding, while we are asking about the origin of epochs as a whole.