Contrary to Alphonso Lingis's claim that radical passivity cannot be the basis for effective ethical agency, this contribution argues that it is precisely the later Levinas's reconceptualized notion of alterity and consequently of subjectivity that makes ethical action — understood as substitution and sacrifice — possible. The argument proceeds by way of a close reading of the "passage to the Third ' inconspicuously located towards the end of Levinas's second magnum opus, Otherwise than Being or Beyond Essence (1974). In response to critique levelled against his early conceptualization of the self as radically independent and autochthonous, the later Levinas introduces the notion of substitution, which entails a self always-already "infected' by the other. The encounter with the other is therefore no longer premised on atheism and autarky, but anarchically located within the self. The other concerns me precisely because the other is not absolutely outside-of-me; the other is the other-within-the same, within me, the essence of my humanity.