NECESSITY

[A105] Necessity, for Kant, is not derivable from experience and, in a strange way (connected with the transcendental unity of apperception), is essential for the objectivity of knowledge and the possibility of experience. All synthesis with concepts involves representing the manifold of intuitions as (in a sense) necessary; "a concept is always, as regards its form, something universal which serves as a rule....But it can be a rule for intuitions only in so far as it represents in any given appearances the necessary reproduction of their manifold, and thereby the synthetic unity in our consciousness of them." [B234] Namely, in the Second Analogy Kant argues that it is a condition for the possibility of experience that we represent appearances as causally determined, as being successively ordered (in the synthesized manifold, as opposed to the manifold as "subjectively" given) according to a necessary rule.

See Necessity, logical or metaphysical