Brentano?" "In Brentano." You have in mind the fact that the first philosophical text through which I worked my way, again and again from 1907 on, was Franz Brentano's dissertation: On the Manifold Sense of Being in Aristotle (1862). On the title page of his work, Brentano quotes Aristotle's phrase: τὸ ὄν λέγεται πολλαχῶς. I translate: "A being becomes manifest (sc. with regard to its Being) in many ways." Latent in this phrase is the question that determined the way of my thought: what is the pervasive, simple, unified determination of Being that permeates all of its multiple meanings? This question raised others: What, then, does Being mean? To what extent (why and how) does the Being of beings unfold in the four modes which Aristotle constantly affirms, but whose common origin he leaves undetermined? One need but run over the names assigned to them in the language of the philosophical tradition to be struck by the fact that they seem, at first, irreconcilable: Being as property, Being as possibility and actuality, Being as truth, Being as schema of the categories. What sense of Being comes to expression in these four headings? How can they be brought into comprehensible accord?

This accord can not be grasped without first raising and settling the question: whence does Being as such (not merely beings as beings) receive its determination?

Meanwhile a decade went by and a great deal of swerving and straying through the history of Western philosophy was needed for the above questions to reach even an initial clarity. To gain this clarity three insights were decisive, though, to be sure, not yet sufficient for the venture of analysing the Being-question as a question about the sense of Being.

Dialogues with Husserl provided the immediate experience of the phenomenological method that prepared the concept of phenomenology explained in the Introduction to Being and Time (§7). In this evolution a normative role was played by the reference back to fundamental words of Greek thought which I interpreted accordingly: λόγος (to make manifest) and φαίνεσθαι (to show oneself).

A renewed study of the Aristotelian treatises (especially Book IX of the Metaphysics and Book VI of the Nicomachean Ethics) resulted in the insight into ἀληθεύειν as a process of revealment, and in the characterisation of truth as non-concealment,

William J. Richardson - Heidegger: Through Phenomenology to Thought