good signifies in Plato and in what way the idea of the good is that which is supposed to render knowledge and truth possible—all this is in many respects obscure. We shall not enter here into the difficulties of Platonic interpretation nor into the demonstration of the connection of the idea of the good with what we discussed earlier regarding the ancient understanding of being, its derivation from production. It appears as though our thesis that ancient philosophy interprets being in the horizon of production in the broadest sense would have no connection at all with what Plato notes as condition of possibility of the understanding of being. Our interpretation of ancient ontology and its guiding clue seems to be arbitrary. What could the idea of the good have to do with production? Without entering further into this matter, we offer only the hint that the idea ἀγαθοῦ is nothing but the δημιουργός, the producer pure and simple. This lets us see already how the idea ἀγαθοῦ is connected with ποιεῖν, πράξις, τέχνη in the broadest sense.
c) The temporal interpretation of existentiell understanding, both authentic and inauthentic
The question about the possibility of the understanding of being runs into something that transcends being, a "beyond." As to what makes understanding of being possible, we shall find it without an image only if we first ask: What makes understanding possible as such? One essential moment of understanding is projection: understanding itself belongs to the basic constitution of the Dasein. We shall inquire further into this phenomenon and its possibility, and to this end we may also recall something noted earlier. Understanding belongs to the basic constitution of the Dasein; but the Dasein is rooted in temporality. How is temporality the condition of possibility for understanding in general? How is projection grounded in temporality? In what way is temporality the condition of possibility for the understanding of being? Do we in fact understand the being of beings by means of time? We shall attempt, first of all, a temporal interpretation of understanding, taking understanding as ontical, existentiell understanding and not yet as understanding of being. We shall then inquire further how our existent comportment toward beings, toward the extant in the wider sense, is grounded as understanding in temporality, and how, further back beyond that, the understanding of being that belongs to this existent comportment toward beings is conditioned on its part by time. Is the possibility and structure of the distinction between being and beings grounded in temporality? Must the ontological difference be interpreted Temporally?
How is existentiell understanding determined by temporality? We heard earlier that temporality is the equally original ecstatic-horizonal unity of