Kant’s Copernicusian REVOLUTION is a well-known topic in history of epistemology, though its implications and impacts are not well discussed enough. No need to mention that analysis of knowledge was Kant’s first philosophical self-commitment. Aspiring of Copernicus’s REVOLUTION in astronomy, he changed the centrality of subject/object in his epistemological approach and maintained that mind (cognitive faculties) must be departure of metaphysical analysis; that was a REVOLUTIONary idea. Doing so, he, as it is well-known, divided all judgments from two different aspects: first, analytic/synthetic; and second, apriori/aposteriori. He, then, argued that there are apriori synthetic judgments -by which the possibility of knowledge is warranted - are universal and necessary. These judgments not only refer to external world, but also belong equally to physics, mathematics, and metaphysics. He believed that his doctrine could (dis)solve the old long-standing epistemological problem in modern philosophy such as the debates on source of knowledge (reason/experience), dogmatism/skepticism, etc., among rationalists and empiricists. Although his ideas, specially stressing on apriori concepts as a key, help him to (dis)solve some epistemological puzzles, either reveal a few new problems in newly changed epistemological scope.