Translated by Pete Ferreira
To say that being in the sense of existence is not a real predicate means, according to this interpretation, that by attributing an existence (an 'external reality') to something you do not add to it some qualitative determination. Now, this not only tells us what Kant means by reality, but also enlightens us about his understanding of the meaning of being in the sense of the existence of the 'outside world'. And through an interpretation of the Kantian concept of Wirklichkeit, of which it will here suffice to only report the outcome, Heidegger comes to the conclusion that for Kant being in the sense of the existence of external reality has the meaning of 'absolute position', precisely absolute position with respect to perception, which is to him the intentional attitude of the subject implicitly considered as determinant.56
Next, Heidegger discusses the argument usually put forward in medieval thought, but dating back to Aristotle, according to which the ontological constitution of the entity includes the two fundamental moments of essentia and existentia; in particular Heidegger examines the different meanings given to these two terms and the problem of their distinction (distinctio) and their connection (complicatio) in the ens creatum. There are three main concepts that Heidegger considers: that of Thomas Aquinas and the Thomistic school, according to which this distinction is to be understood in the sense of a distinctio realis; that of Duns Scotus and the Scotist school, which instead understands it as a distinctio modalis; finally that of Suarez, for whom the distinction is a distinctio rationis.
Starting from this discussion of these three concepts, Heidegger then goes back to the Greek origins of this distinction, to show the roots of ontology in Greek thought, and then advances up to Kant, to show how Kantian metaphysics depends on scholastic ontology.
Heidegger made this reconstruction, outlining the history of the distinction of essentia and existentia, by starting from medieval ontology, returning to the Greeks and arriving at Kant, with the intent of grasping what is the understanding of the being that underlies this distinction, and which is the intentional attitude of man that he presupposes to be the decisive attitude. The result which Heidegger arrives at – among other things through an interpretation of Plato which is a prelude to the later allegory of the cave57– is that the attitude to be considered as decisive is the productive attitude, the technical-practical attitude, which requests a preliminary distinction of essence (in the sense of form and model) from the moment of its realization, that is, of the granting to it of an existence in matter.58
56 See GA 24, §§ 7-9. On Kant's thesis that existence is not a real predicate, Heidegger returns briefly to it during winter semester 1929/30 in the context of an interpretation of the Aristotelian concept of λόγος. There he observes that the Kantian thesis coincides with the thesis that Aristotle enunciates at the end of the third chapter of the De interpretatione, that being or not being are not signs of the thing (οὐδὲ γαρ τὸ εἶναι, ή με εἶναι σημεῖον ἐστί τοϋ πραγματος, 16 b 22-23) (see GA 29/30, 469-473).
57 See GA 24, 400-405.
58 Ibid, § 10-12.