“The state of mind in the representation of something beautiful must be a feeling of the harmonious free play of the powers … of imagination (gathering together the manifold of intuition) and understanding (supplying the concept uniting the representations).” Kant, Critique of Judgment §9
According to Rousseau, primal man lived in a world of melody, whereas the modulation of harmony testifies to a fall equivalent to the fall of language after Babel. Harmony follows a regular, that is, regulated measure. Harmonious play is by definition not free. This means that the beautiful that Kant speaks of is not an absolute free play, but a play that is free and follows the laws of harmony. But if it is to be free and submit to a law, this law must be autonomously posited by the play itself. According to the form of his transcendental argumentation the free must be understood as referring to a higher aesthetic law, which the “powers” (of imagination and understanding) give unto themselves. Structurally, the aesthetic law is analogous to the categorical imperative, or the moral law.
Thus, to experience something beautiful is to be free in accordance with a law posited by the experiencing of beauty. This law must have universally valid and necessary (this is not to say anything about what the content of beauty is, only about its form: not that a particular painting is beautiful, but that the beauty of painting is experienced in the same way by anyone who finds it beautiful). There is no set definition for the harmonious, but only that we will perceive harmony according to our mode of imagining and understanding.
Thoughts fallen by the wayside 