106  Engaging Heidegger

of the allegory in the context of a further unfolding of the themes of Sein und Zeit (published in 1927). Here again he observes that ‘what we are in search of is the epekeina tes ousias.’⁹ What is ‘beyond being[ness]’ is the Idea of the Good that makes possible or is ‘the condition of the possibility’ for all knowledge and truth about beings in their beingness.¹⁰ This time around, he more explicitly works out the correspondence of the Idea of the Good with the image of the sun, which he identifies as the light-source for all visible light, the light-source that is seen only indirectly: ‘For seeing with the eyes there is required not only eyes and not only the being that is seen but a third thing, [namely], phos, the light, or, more precisely, the sun, helios.’¹¹ Thus, as he had a year earlier, Heidegger appropriates Plato’s metaphor of light in order to unfold his ownmost concern and the fundamental matter for thought, namely, the (temporal, finite and negatived) enabling/letting/giving of beings and their ontic truth. As he expresses this: ‘The basic condition for the knowledge of beings as well as for the understanding of being[ness] is: standing in an illuminating light.’¹² And further: ‘The understanding of being[ness] already moves in a horizon that is everywhere illuminated, giving brightness’ (his emphasis).¹³

These texts from the 1927 lecture course provide the key to a more complete understanding of his notion of die Lichtung in Being and Time. As Heidegger observed many years later, it was in Being and Time that he first introduced the term die Lichtung, and I have discussed his effort in §28 to rethink and recast the early Christian and medieval metaphysical metaphor of the human lumen naturale (natural light) in fundamental ontological terms as Dasein’s (always-already) disclosing activity (legein as hermeneuein) that enables all beings to be meaningfully in language.¹⁴ Ontologically, Dasein is this ‘lighting’ itself, he maintains, and not, in the first place, an ontic entity that possesses the ‘natural light’ of reason.

This much is clear from a careful reading of the text in §28, yet it is to §69 that we need to turn in order to make a fi rmer connection with Heidegger’s reading of Plato’s allegory. In the opening part of §69, he restates the characterization of Dasein’s ontologically disclosive character more explicitly in terms of temporality, observing (with emphasis) that ‘ecstatic temporality lights [lichtet] the “there” primordially.’¹⁵ In other words, it is Dasein’s temporally disclosive existence itself that makes possible all ontic truth about beings. Figuratively, he refers to this ontological structure of Dasein as a special kind of ‘light’ – that is, as the light that is the source for all that is seen in the light: