§20. Temporality [400-402]

problems. There is no occasion here to delineate the Platonic order of inquiry in further detail. But a rough reference to it is necessary so that the view may be progressively dispelled that our fundamental-ontological problem, the question about the possibility of the understanding of being in general, is simply an accidental, eccentric, and trivial rumination.

At the end of the sixth book of the Republic, in a context that cannot occupy us in further detail here, Plato gives a division of the different realms of beings, with particular regard to the possible modes of access to them. He distinguishes the two realms of the ὀρατόν and the νοητόν, things visible to the eyes and things thinkable. The visible is that which is unveiled by sense, the thinkable that which understanding or reason perceives. For seeing with the eyes there is required not only eyes and not only the being that is seen but a third, φάος, light, or, more precisely, the sun, ἥλιος. The eye can unveil only in the light. All unveiling requires an antecedent illumining. The eye must be ἡλιοειδής. Goethe translates this by "sonnenhaft" [like, of the type of, the sun]. The eye sees only in the light of something. Correspondingly, all non-sensible cognition-all the sciences and in particular all philosophical knowledge—can unveil being only if it has being's specific illumination—if the νοεΐσθαι also gains its own specific φάος, its light. What sunlight is for sensuous vision the ἰδέα τοῦ ἀγαθοῦ, the idea of the good, is for scientific thinking, and in particular for philosophical knowledge. At first this sounds obscure and unintelligible; how should the idea of the good have a function for knowledge corresponding to that which the light of the sun has for sense perception? As sensible cognition is ἡλιοειδής, so correspondingly all γιγνώσκειν, all cognition, is ἀγαθοειδές, determined by the idea of the ἀγαθόν. We have no expression for "determined by the good" which would correspond to the expression "sunlike." But the correspondence goes even further: τὸν ἥλιον τοῖς ὁρωμένοις οὐ μόνον οἶμαι τὴν τοῦ ὁρᾶσθαι δύναμιν παρέχειν φήσεις, ἀλλὰ καὶ τὴν γένεσιν καὶ αὔξην καὶ τροφήν, οὐ γένεσιν αὐτὸν ὄντα.3 "You will, I believe, also say, the sun furnishes to the seen not only the possibility of being seen, but gives to the seen, as beings, also becoming, growth, and nurture, without itself [the sun] being a becoming." This extended determination is correspondingly applied to knowledge. Plato says: καὶ τοῖς γιγνωσκομένοις τοίνυν μὴ μόνον τὸ γιγνώσκεσθαι φάναι ὑπὸ τοῦ ἀγαθοῦ παρεῖναι, ἀλλὰ καὶ τὸ εἶναί τε καὶ τὴν οὐσίαν ὑπ᾽ ἐκείνου αὐτοῖς προσεῖναι, οὐκ οὐσίας ὄντος τοῦ ἀγαθοῦ, ἀλλ᾽ ἔτι ἐπέκεινα τῆς οὐσίας πρεσβείᾳ καὶ δυνάμει ὑπερέχοντος.4 "So then you must also say that the known not only receives its being known from a good,

3. Plato (Burnet), Republic, 6.509b2b4. [Politeia, in Platonis opera, ed. John Burnet, vol. 4 (Oxford: Clarendon Press, 1899).]

4. Ibid., 509b6b10.

Basic Problems of Phenomenology (GA 24) by Martin Heidegger