December 12, 2012
Kant and Descartes
“Idealism is the assertion there are none but thinking thing beings. All other things, which we believe are perceived in intuitions, are nothing but presentations in the thinking things, to which no object external to them in fact corresponds. Everything we see is just a construction of the mind.” (Prolegomena). Idealism maintains that there are no objects in the world, only minds. According to idealism, the existence of outer objects is uncertain and ambiguous. Idealism is the group of philosophies asserting that actuality is fundamentally mental, or otherwise intangible. Kant holds the belief that objects only exist as perceptions is fundamentally idealist. The argument begins by making the point: our senses never enable us to experience things in themselves, but only know their appearances. This idea depicts space and time as empty forums to determine how things appear. Kant discusses how math consists of synthetic a priori cognitions, or the ability to provide new information that is necessarily true, and its relation to geometry. Kant believes there is some form of pure intuition innate within us. This innate intuition is what allows us to identify different notions without reference to sense experience.
In the opinion of Kant, the possibility of mathematics rests upon the possibility of “synthetic propositions a priori”. (Prolegomena). There is a priori certainty of geometry. A priori knowledge or justification is independent of all experience. A priori judgments are based upon reason alone, independently of all sensory experience, and therefore are applicable with universality. According to Kant, “Geometry is based upon the pure intuition of space.” (Prolegomena). We cannot have any perceptions of objects if not in space and time. Kant declares, “it must first exhibit its concepts in intuition, and do so a priori, in an intuition that is not empirical, but pure.” (Prolegomena).