We shall follow some of the details of this argument in the remainder of this chapter. But let us begin by situating, in a preliminary way, Aristotle's understanding of πρᾶξις and of practical wisdom in relation to theoretical or speculative knowledge. We shall do so within the context of Heidegger's reading.
Heidegger's discussion of φρόνησις concentrates initially on Book VI of the Nicomachean Ethics, where Aristotle describes five ways in which the soul attains truth (ἀλήθεια) in affirmation or denial, that is, by way of the λόγος. These are identified as τέχνη, ἐπιστήμη, φρόνησις, σοφία, and νοῦς. Judgment (ὑπόληψις) and opinion (δόξα) are said to be capable of error or falsity. All these belong to the virtues of the "intellectual" or "noetic" part of the soul (νοητικῶν) (NE, 1139b12).
Truth is here considered insofar as it can be apprehended by the soul itself. The soul, according to Aristotle, has two parts, one having λόγος, the other without it (NE, 1139a5). Furthermore, there are two ways of having λόγος: a) επιστημονικόν, the epistemic or "scientific" faculty, and b) λογιστικόν, the deliberative faculty. The first is concerned with episteme; the second with deliberation (βουλεύεσθαι). The distinction is made on the basis of the kind of knowledge that each provides. The epistemic faculty is concerned with the contemplation (θεωρεῖν) of those things whose ἀρχαί are invariable, the deliberative faculty with things that are variable: not simply things that can "change" or move, as Heidegger explains, but things that in their very being can be otherwise than they are.
Heidegger frames his reading of Book VI in the following manner. With respect to these two faculties, the task is to ascertain which disposition (ἔχις) of each faculty is best. The criterion for this will be the question of which disposition best discloses the ultimate ἀρχή or being of things. In the case of the epistemic faculty it will be shown to be σοφία; in the case of the deliberative faculty, φρόνησις. The question will then arise of which of these two dispositions has priority. A comparative examination of the different kinds of knowing as dispositions of having λόγος is thus entailed.
Aristotle begins his comparative investigation by considering ἐπιστήμη. Epistemic knowledge has as its object something that exists of necessity and is eternal (ἀίδιον). Its object cannot be subject to growth or decay (it is αγένεια) (NE, 1139 b24). And this means that its being must remain constant even when the object is not being observed or contemplated: epistemic knowing must dispose over its object even ecö tou θεωρεῖν, "outside of an actual beholding at any given moment," as Heidegger puts it. The knowing characteristic of ἐπιστήμη, as a manner of disclosure, can thus be seen as the preservation of the discoveredness of its object. It uncovers and preserves in such disclosedness the being of its object, yet in a very specific way. Heidegger states: