30 Phil, Chapter 28, Kant, Touchstone 72: Transcendental Idealism.

The Split and Three-Tine Fork: Transcendental Idealism is Kant’s view on epistemology. His distinction between phenomena and noumena and his three-tiered approach to knowledge. Kant introduced a crucial distinction between phenomena—the world as we see and understand it—and noumena—the world as it exists independently of our perception. 

Kant chose a three-tine approach to knowledge. Analytic A Priori statements are a subset of Rational Ideas, the true by definition ones. The ideas that are of the mind only (Analytic). Synthetic A Priori statements are another subset of Rational Ideas that tell us something new about the Material World (synthetic). Synthetic A Posteriori statements are empirical ideas about the world and are therefore verifiable.