Emmanuel Levinas, answered from the texts and cited to the page.
The self is not first an autonomous freedom that then encounters others and elects to be responsible for them. The self is constituted, at a level deeper than its self-consciousness, by having always already been substituted-for-the-other.1 The "here I am" (me voici) is in the accusative — the I in the oblique — not the nominative I that posits itself. Otherwise Than Being (1974) is where this is fully developed; Totality and Infinity (1961) was, as I noted in the 1979 preface to the Quadrige reissue of Time and the Other, still too ontological — it spoke of the face-to-face in a language of separated terms in relation, when the relation itself is more anterior than the terms it joins.
The mature analysis is harsher: the subject as hostage (otage) for the other, persecuted by the other, in-debt-before-any-debt, responsible even for the other's own freedom and failures. The structure is not psychological masochism; it is the philosophical articulation of how subjectivity is constituted. Freedom comes after, as the response that the prior assignation makes possible. The "I" arises through having been called from outside, not through self-positing.23
Not a victim offering itself in his place, which would suppose there is a reserved region of subjective will behind the subjectivity of substitution. It is the null-place in which inspiration by the other is also expiation for the other, the psyche by which consciousness itself would come to signify.Otherwise Than Being, or Beyond Essence, p. 187
The uniqueness of the ego, overwhelmed by the other in proximity, is the other in the same, the psyche. But is it I, I and no one else, who am a hostage for the others. In substitution my being that belongs to me and not to another is undone, and it is through this substitution that I am not "another," but me.Otherwise Than Being, or Beyond Essence, p. 168
It is like a despite myself that is more me [moi] than myself: it is an election. Every me is elected or chosen: no one else can do what it must do. This is the meaning of "and I more than all the others" in Dostoyevski.God, Death, and Time, pp. 198–199
The substitution thesis is the most demanding doctrine in the late authorship and the most likely to be misread. Read psychologically, it sounds like religious masochism — the self as scapegoat, persecuted-by-design, glorying in suffering. The psychological reading is not what the analysis says. Substitution is a structural claim: that the structure of subjectivity is response to a call already addressed, not the self-positing of a free agent. The structural claim has Pauline and Christian resonances I do not refuse, but it also has unmistakable Jewish ones — the prophetic figure who says "send me" (Isaiah 6:8), the Talmudic principle of bearing the other's burden — and the analysis is philosophical rather than confessional. Bernasconi's Cambridge Companion chapter ("What is the question to which substitution is the answer?") gives the most careful reading: substitution answers the question of how a subject can be ethical at all if ethics is the relation that constitutes the subject. The answer is that the subject is constituted as already-responsible; substitution names the structural depth at which the call has always already been received. Critchley reads the substitution doctrine as the late deepening of the ethics-of-deconstruction; Putnam works with the structural reading and pushes back on the "hyperbole"; the philosophical-theological reception of substitution as testimony has carried the doctrine into broader religion-philosophy debates than I can survey.