I proceed from the hypothesis that the difficulties in Kant’s presentation of his plan and, accordingly, the implicit reason for the critical attitude to this plan on the part of many contemporary philosophers stem from the fact that he had no theoretical link at his disposal which would offer a more solid scientific grounding for his entire system. I believe that Darwinism is such a link which bolsters the central but ungrounded thesis of the Critique of Pure Reason on the (...) existence of a priori synthetic judgments. The synthesis of Darwinism and critical philosophy dictates, however, a substantial restructuring of the latter since some of its key elements prove to be weak in the light of modern studies and need to be revised or even reversed. The first reversal explored in this article determines the origin of the categories which are now revealed not “from the top down” where Kant sought them, i. e. not in logical functions in accordance with metaphysical deduction and not in self-consciousness as transcendental deduction claims, but “from the bottom up” if one considers things in the evolutionary dimension, i. e. in the instincts. The second reversal shifts the freedom of will which Kant placed in the same ontological basket with things in themselves at “the top,” to another level of the pyramid of ontologies, by changing dualism to pluralism because dualism is too narrow to accommodate all the autonomous components of critical philosophy. Thus spirit and freedom find a new place separate from the sphere of physical nature; the category of adaptation explains how different ontologies can coexist; while the problem of two interpretations of transcendental idealism (two-world vs. two-aspect interpretation) finds a solution through their reconciliation. (shrink)