Abstract
Taking the question of phenomenality as its guiding thread, this paper attempts to shed light on the relationship between Heidegger's turn and Derrida's 1964/65 seminar on Heidegger. I argue that deconstruction can be understood as a performative attempt to take into account Heidegger's thinking of originary semblance or errancy, which already announces itself in Sein und Zeit and is a central figure of what the later Heidegger calls ‘the turn’. Instead of trying to grasp this errancy or this différance phenomenologically, Derrida takes up the necessity to read and repeat what is already given, what already appears, and thereby undermines, through his reading of Heidegger's Crossing Out of the Word ‘Sein’, the phenomeno-fundamental ontological approach of Sein und Zeit, or rather: shows that it is always already undermined.