The complication of πρᾶξις thus threatens to interrupt the story of a purely natural genesis of theoretical life. If there is a natural hierarchy of human vision and knowing, then such a hierarchy must first be grounded with respect to the λόγος itself. More precisely, it must demonstrate its legitimacy with respect to the relation between λόγος and desire, that is, with respect to the nature of the intrinsic possibilities and limits of human πρᾶξις. In the 1924/25 Sophist course, Heidegger investigates precisely this complication via a reading of Aristotle's Nicomachean Ethics that focuses on Books VI and X. The entire interpretation hinges on the question of the relative priority of practical or theoretical wisdom, of φρόνησις or σοφία as discussed by Aristotle at the end of Book VI. Indeed, Heidegger's reading of Metaphysics Book I occurs within an interpretation of the Nicomachean Ethics oriented toward understanding the respective claims of φρόνησις and σοφία to be the highest mode of ontological disclosure. In the current section, we shall follow Heidegger's initial analysis that seeks to locate φρόνησις in a preliminary manner with respect to the other forms of knowledge examined in Book VI of the Ethics. We shall then be in a position to examine Heidegger's interpretation of the relation between theoretical and practical knowledge with regard to their modes of "seeing," considered as modes of disclosure.
Book I of the Metaphysics indeed appears to allude to the Nicomachean Ethics as explicating the distinction between τέχνη, ἐπιστήμη, and other forms of knowledge (M, 981b26). Practical knowledge and its most excellent form, φρόνησις or practical wisdom, seems to differ in principle from theoretical or speculative knowledge, simply because practical knowledge is always already involved in a particular πρᾶξις. It does not have time to turn away or take a contemplative distance from the concrete situation of its immediate involvement. The horizon of πρᾶξις thus seems to lie outside that of θεωρεῖν. And we might therefore expect practical knowledge to be