What could a postmetaphysical ethics be? And why think it from the vantage point of the work of Kierkegaard and Derrida? These two questions guide this work and emerge from this initial a postmetaphysical ethics would move away from Heidegger’s criticism of the ethical as a practical domain separated from theoretical intellection. Heidegger sought to demonstrate that the ethical—as a specific practical domain that attempts to propose norms and rules of action and is different from the theoretical—is in itself metaphysical. Metaphysics is the distinction between the theoretical and the practical. That the divergence between the theoretical and the practical, the ideal and the real, the ontological and the ethical, ceases to be decisive signifies, above all, the toppling of the classical opposition between faith and knowledge, believing and knowing, that is, the toppling of the consequences that arose from the border that divided reason and “unreason,” philosophy and religion. In determining the extent to which the question of belief can be examined in relation to postmetaphysical ethical thought, the author argues that a postmetaphysical ethics would be one for which belief, and in particular the belief in the other, is no longer irrational waste but the Archimedean point of the emergence of the postmetaphysical ethics itself. Kierkegaard and Derrida can teach us to think the configuration of an ethics whose center is inhabited by no other duty than the impossible, aporetic, and undecidable duty to believe