It would be a grave mistake, however, to think that this ambivalence of ὄν   [òn] is something peculiar to Aristotle  . The fact is that it characterizes the entire history of Greek thought. The primitive form of ὄν, Heidegger claims, is most probably ἐόν [eon], as the word is found, for example in Homer   (v.g. Iliad, I, 70), or even in Parmenides   and Heraclitus  . The ἐ- would indicate the stem ἐσ- (hence ἔστιν [estin], est, ist, is), in whose dynamic power the participle shares in double fashion. What is more, in Parmenides and Heraclitus, ἐόν can mean, in addition to the ambivalence we have mentioned already, the ultimate and unique process that we know as one-in-many (ἔν-πάντα   [en-panta]). That is why the author, in a much later expose (1957) of the onto-theo-logical structure of metaphysics, feels free to meditate the ambivalence of ὄν under the guise of Heraclitus’ ἔν [en], which in turn is identified with λόγος   [logos], conceived as the process of grounding beings. ἔν, the grounding process, is correlative with πάντα, the ensemble of beings that are grounded, and the correlation is so intimate that one correlate cannot “be” without the other: ἔν can no more serve as ground unless πάντα be grounded than πάντα can be grounded without ἔν. This intimate correlation between ἔν and πάντα [panta], intrinsic to the Heraclitean λόγος [logos], corresponds precisely to the duality of Being and beings that we call the “ambivalence” of ὄν. What is more, out of the ambivalence in λόγος arises even for Heraclitus the same ambiguity that we find later in the structure of metaphysics: ἔν is unifying one in the sense of the absolutely primary and universal; ἔν is that unifying one in the sense of that being, supreme among the πάντα (for Heraclitus: Zeus), which grounds the rest because it is in some way or other the “fullness” of ἔν in the first sense. [RHPT:10-11]