from Stanford encyclopaedia of philosophy:
Of particular interest, within Kant’s account of fine art, is his discussion of how beautiful art objects can be produced (§§46-50). The artist cannot produce a beautiful work by learning, and then applying, rules which determine when something is beautiful; for no such rules can be specified (see the sketch of the Second Moment in Section 2.1 above). But, Kant makes clear, the artist’s activity must still be rule-governed, since “every art presupposes rules” (§46, 307) and the objects of art must serve as models or examples, that is, they must serve as a “standard or rule by which to judge” (§46, 308). Kant’s solution to this apparent paradox is to postulate a capacity, which he calls “genius,” by which “nature gives the rule to art” (§46, 307). An artist endowed with genius has a natural capacity to produce objects which are appropriately judged as beautiful, and this capacity does not require the artist him- or herself to consciously follow rules for the production of such objects; in fact the artist himself does not know, and so cannot explain, how he or she was able to bring them into being. “Genius” here means something different from brilliance of intellect. For example, Newton, for all his intellectual power, does not qualify as having genius, because he was capable of making clear, both to himself and others, the procedures through which he arrived at his scientific discoveries (§47, 308-309).