Subject and object undoubtedly form the two foundations of philosophy in both theoretical and historical contexts. Philosophy, especially epistemology, is based not just on a subject that perceives through the senses and cognizes through the concepts, but also on the object that is perceived and cognized. Ideally, every philosophy should treat these two factums equally, without giving preference to one factum over another. However, philosophy has historically been characterized by an alternating prioritization between these absolutely different domains of reality. While the pre-Socratics sought the most elementary and uniform substance from which the diversity of objective reality arose, the factum of the object was clearly preferred over that of the cognizing human subject. Such prioritization was reversed with every epistemological turn in the history of philosophy, as exemplified particularly in the philosophy of Socrates in antiquity and Descartes in the early modern period. Nevertheless, the emergence of a transcendental subject seems to have followed a historical course. While space and time were ultimately considered objectively by Descartes and post-Cartesian philosophers in early modernity, they were, as is well known, apriorized by Kant in his transcendental aesthetic and attributed as a priori notions to a transcendental subject. However, if the bodily and extra-bodily extended senses are examined individually, it follows that the spatial extension and temporal simultaneity of sensory perceptions are rather dependent on objective or material phenomena. What is at stake here is a synthetic nexus between the subjective-secondary qualities of the senses and the objective-primary qualities of space and time. This seems to presuppose a renewed equivalence of the subject and the object within the framework of sensory perceptions and, accordingly, the necessary correlation and complementarity between philosophical and scientific epistemologies.