In this transcript of a conversation between Simon Critchley & Badiou on Badiou's book Being and Event, Badiou states:
And after that, I have also to understand why there is in modern times a clear relationship between poetry and philosophy. As you know, it’s a Heideggerian idea: this renewal of a philosophical interest in poetics is fundamentally in the Heideggerian field. So it’s a great discovery of Heidegger that we have to learn something essential from poetry.
First, I note that Badiou talks of a renewal so that this approchement is merely the latest rapprochement.
Now, what is this great discovery and something essential? Is this something that Heidegger learnt from reading Hölderlin? (In fact, Heidegger delivered a lecture course on a single poem of Hölderlin's The Ister (The River) in 1942.) Is this discovery a source for Critical Theory in Literary Studies?
Holderlin was certainly interested in Heraclitus. But I don't want to posit Hölderlin as merely a middle term between Heraclitus and Heidegger. Rather as Badiou himself says (in the same conversation) to see the poetic situation and subjectivity speak itself:
What is for poetry the very nature of a situation? ...I think that a poetic situation is always a situation in language...it’s the state of affairs in the expressive dimension of language. What is a poetic event? It’s always the birth of a new possibility of naming inside the language,...[it] is the creation of the possibility of naming that which was without name...The consequences of a poetic event are the creation of poems and the appearance of a new poetic subjectivity – Romanticism, Surrealism, and so on. That is not too complicated. But we can say that there is always in every truth procedure a poetic moment.