Richardson (2003:30-31) – A "revolução copernicana" de Kant

[…] the proper sense of the famous “Copernican revolution,” sc. that ontic knowledge is rendered possible only by an ontological comprehension that precedes it and resides in the very structure of the knower. [1]

How Kant  ’s effort to thus lay the groundwork for ontology becomes a Critique of Pure Reason will appear, if one recalls that “pure reason” is Kant’s term to describe that capacity by which man knows according to a priori   principles. The ontological knowledge which he wishes to explain, however, must be of such a type. As a knowledge, it would consist in judgements (Kant does not   dispute here the Leibniz  -Wolff tradition  ), and, indeed, synthetic judgements, since it would be a knowledge of beings other than the knower and must achieve the union of knower and known (synthesis  ). Yet because these judgements are ontological (pre-ontic), they are prior to all experience (a priori). The grounding of ontological knowledge, then, will involve the study of synthetic a priori judgements (principles), and, more radically, it will involve the delimiting and delineating (therefore “critique”) of the essence of that power in man which forms them (pure reason). Fundamental ontology for Kant had to be a Critique of Pure Reason [GA3  :22-23].

Such a critique is essentially an analysis of transcendence, sc. the transcendence of the human mind. Insofar as this ontological comprehension of a being precedes the ontic cognition of this being, rendering this cognition possible, it is such an orientation of the knower towards the known that it constructs not only the term of this orientation but the horizon   itself within which this being can be experienced in the empirical synthesis  . Such is the a priori synthesis of ontological knowledge: the passage of pure reason beyond itself to the beings-to-be-known in such a way as to comprehend the Being that makes them what they are prior to any experience of them. The examination of the conditions which render such transcendence possible will [31] be itself “transcendental  ,” Kant’s fundamental ontology a transcendental philosophy [GA3:24-25].