This paper examines subjectivity as a structural and ethical problem emerging from the destabilization of metaphysical substance. Departing from the classical conception of the subject as a reflection or modification of substance, the paper evaluates the reciprocal dependence between subjectivity and substance. Through close readings of Sartre’s Nausea and Dostoyevsky’s Notes from Underground, it traces the demystification of substance and the consequent dissociation of the subject. This analysis demonstrates how this collapse produces a form of subjectivity that is no longer anchored by the apodictic foundations of metaphysics – revealing an ethical condition marked by contingency, negation, and a narcotic constancy to nothingness.