This paper outlines the basic traits of a responsive phenomenology by focusing on the issue of originary substitution. On the one hand, a phenomenology of alienness or otherness and an ethics of the other in the sense of Levinas will prove to be closely bound up with this sort of substitution. On the other side, this substitution can be concretised by transitional figures such as the advocate, the therapist, the translator, the witness, or the field researcher; they all intervene from (...) the position of a Third without closing the fissure which opens between ourselves and the Other, between the own and the alien. Precisely by focussing on the issue of substitution, we have the opportunity to outline the basis traits of a responsive phenomenology and to discuss some of its institutional consequences. (shrink)