The notion of aesthetic ideas is of great importance to Kant's thinking about art. Despite its importance, he says little about it. He characterizes aesthetic ideas as representations of the imagination and says that the gift of artistic genius is the inscrutable capacity to envision them. Furthermore, they are counterparts of rational ideas. Works of art thus sensibly present rational ideas; the pleasure they occasion is a consequence of the enriching process of reflection upon the wealth of content they sensibly present. The purpose of this article is to ask whether all rational ideas have aesthetic ideas as counterparts, and so can be presented in art, or whether only some do and which. The answer should reveal what, for Kant, is the subject-matter of art. I argue that for Kant art is concerned with the range and variety of human freedom as well as with its highest fulfillment in morality.