The preceding chapter suggests that the significance of the Anticipations of Perception can be ultimately located in the substitution of logical and qualitative opposition between reality and negation, which for Kant characterizes realitas noumenon, the reality that is object of the pure intellect, with the real and quantitative opposition that is the characteristic feature of realitas phaenomenon, that is, the "reality that corresponds to sensation." If this distinction still appears to be a secondary aspect of critical thought, a look at the history of post-Kantian Idealism immediately shows that this conviction is unfounded.