Kant claims that the mind makes an active contribution to experience (KantÆs). His argument was designed to show the limitations of knowledge. While the Rationalists suggested that we could have metaphysical knowledge of God, souls, substance, etc., and that such knowledge was transcendentally real, Kant maintained that we cannot have knowledge of the realm beyond the empirical. In other words, transcendental knowledge is ideal, but is not real in the human mind. Kant identified a priori sources of these constraints. He believed the mind has a receptor capacity, which he called the sensibility, and that it possesses a conceptual capacity, or the understanding. Kant argues that sensibility is the understandingÆs means of accessing objects. In other words, we can only access what is real.
Synthetic a priori judgements are possible in geometry because space is an a priori form of sensibility (Guyer; KantÆs). We can know the claims of geometry a priori only if experiencing objects in space is the necessary mode of experience. Kant argues that we cannot recognize objects without being able to represent them spatially, without being able to delineate the area they occupy. Without this spatial representation, our sensations remain undifferentiated and we cannot ascribe properties to particular objects. He argues that time is also necessary for us to form intuitions of objects. The idea of time cannot be gathered from experience because it is impossible to see the succession and simultaneity of objects which would indicate the passage of time. We could not experience objects if we did not already possess the capacity to represent objects in time.
The basis of KantÆs view of knowledge, then, is that you must be able to get an image of something in time and space to be able to understand it (KantÆs). The thing must have a concrete existence outside the stream of consciousness going on inside the mind. The thing mus...