In Kant’s Critique of Pure Reason, the first part, Transcendental Doctrine of the Elements, and the subsequent Transcendental Aesthetic clearly form a propaedeutic to his transcendental philosophy, to the philosophical-programmatic transcendentalism in general. Like his predecessors in early modern philosophy, Kant deploys the method of epistemological negation and separation in the first part of his Critique of Pure Reason in order to completely apriorize the domain of sensibility and thereby to give it an infallible transcendental status. In a two-stage method of negation and separation, which seems to mark an extension and continuation of the epistemological negation initiated by Descartes in the early modern period, Kant dares to declare the primary-qualitative forms of sensibility, namely space and time, as merely subjective a priori representations, and thereby subsume them under a superordinate context of transcendentalism. However, Kant does not mention a purely aesthetic space of sensibility, that is, the spatiality of the senses, especially of vision, which differs from the geometrically abstract Euclidean space, from which alone Kant gives examples for the a priori status of spatial perception within the framework of a transcendental aesthetic. That the Euclidean-geometric space is an a priori conception of space is a tautology. By programmatically apriorizing space and time as forms of sensibility, Kant tacitly suppressed the discourse prevalent in the early modernity on the spatial extension of senses, especially of vision. The a priori nature of space and time, as emphasized by Kant, should therefore be re-examined. Since the senses directly connect the subject to the body and extra-bodily objects, sensory spaces cannot be reduced to mere subjective a priori representations; that is, the senses can hardly be ascribed a completely transcendental status.