Epistemological opacity and the historical formation of descriptive psychopathology in French alienism

Epistemological opacity designates a recurrent tension within the clinical encounter, the point at which psychiatric categories make experience intelligible while also revealing their own insufficiency. It is not simple ignorance, nor merely a gap awaiting future clarification, but a historically productive relation between clinical experience and the conceptual frameworks designed to organize it. This article argues that such opacity was not peripheral but constitutive of 19th-century descriptive psychopathology. Once we move beyond the opposition between teleological histories of progress and constructivist accounts of psychiatric knowledge, the clinic appears as a theory-laden instrument whose limits were repeatedly encountered in practice. Two exemplary sites make this clear: hallucination and the genesis of delusion. In both cases, descriptive psychopathology advanced not by tightening its definitions, but by confronting what could not be made to fit them; by learning to work with the residue of experience that escaped signification. Thus, this article treats limits of intelligibility not as a threat to psychiatric realism, but as one of its conditions. Methodologically, it draws on historical epistemology to examine how these limits become visible in the textual traces left by alienist clinicians when their categories proved insufficient to stabilize clinical experience. Psychiatric knowledge is not secured by the exhaustive precision of its categories, but by their capacity to remain responsive to what they cannot fully represent.