The subject is the object: On the emergence of subjective science in thirteenth-century theology

This article examines a fundamental transformation in thirteenth-century theory of science by tracing the shifting role of the subiectum scientiae in scholastic theology. While Aristotelian epistemics defined a science through a unitary subject conceived as a logical genus, medieval debates-especially within the Parisian university context-revealed increasing tensions when applying this framework to theology. Focusing on key figures such as Robert Kilwardby, Thomas Aquinas, and Giles of Rome, the article reconstructs an epistemological turn whereby the subject of science was progressively reinterpreted in relation to the intellect and its objects. Kilwardby's essentialist redefinition of the subject as a unified nature laid the groundwork for this development. Aquinas advanced it further by integrating the notion of obiectum and emphasizing the role of the intellect, introducing a dual account in which both subject and formal object contribute to the unity of a science. The decisive shift occurs in Giles of Rome, who effectively collapses the distinction by identifying the subject with the principal object of cognition, thereby centering epistemology on the relation between intellect and object. This reorientation foregrounded the limits of human cognition and intensified debates about the scientific status of theology, particularly in contrast to divine and beatific knowledge. The article argues that these developments culminate in an emergent notion of "subjective science," wherein the identity and validity of scientific knowledge become inseparable from the capacities of the knowing subject. This medieval trajectory, far from being anachronistic, offers a historically grounded account of the epistemic conditions that anticipate later conceptions of subjectivity.