Delineation of the Thematic Field, with ἀληθεύειν as the
Point of Departure

§27. What has been accomplished up to now and the future task.
What has been accomplished: the acquisition of the point of
departure (= ἀληθεύειν). The task: the delineation of the theme,
with ἀληθεύειν in Plato (= διαλέγεσθαι) as the point of
departure. First indication of the theme: a revolution in the concept
of Being; the Being of non-beings (= ψεῦδος).

Our considerations thus far have had the sense of a preparation for understanding a scientific dialogue of Plato. I expressly emphasize "a scientific dialogue" in order to indicate that not all Platonic dialogues attain this height of scientific research, although all of them in a certain way aim at knowledge. There is no scientific understanding, i.e., historiographical return to Plato, without passage through Aristotle. Aristotle at first blocks, as it were, every access to Plato. This is obvious when we consider that we always issue from the later ones, and it is as ones who are still later that we go back to the earlier ones, and that there is in principle no arbitrariness within the field of philosophical reflection. In a historiographical return to the basic sources of our spiritual existence, we must rather adhere to the inner current of historical development. Choosing a philosophy or a philosopher is never arbitrary. For the rest, it might be permitted to select spiritual hobbies, on the basis of the most diverse motivations, from the history of ideas, examples, and possible existences—hence to deal with history arbitrarily—yet this permission does not apply to philosophical research, if indeed this research is to uncover Dasein in its foundations and if this Dasein is history, i.e., if we ourselves are history. In this way the passage through an interpretation of Aristotle, whether explicit or not, is basically something obvious, especially if we consider that Aristotle's own research is nothing else than a more radical apprehension of the same problems with which Plato and earlier thinkers had grappled.

1. Continuation of the lecture course after the Christmas recess of 1924-25. Heidegger's manuscript contains the titles: "Recapitulation, Introduction" and "Transition."

From this point on, the present text is based not only, as was previously the case, on Heidegger's handwritten manuscript and on the lecture notes of H. Jonas, F. Schalk, and H. Weiß, but, in addition, on a typewritten copy of the stenographic lecture transcript of S. Moser, which begins only after the Christmas recess. This copy was reviewed by Heidegger, authorized, and annotated with marginalia which will be presented in the text separately, marked "AH" (= Heidegger's annotation of the Moser transcript).