"Reason is not the power of reconciliation, but the art of division." With this guiding principle, Martin Seel characterizes his investigations into the concept of aesthetic rationality as a contribution to the critique of multidimensionally constituted reason. "Aesthetic rationality" is ambiguous. The rationality of the aesthetic: Here, Seel refers to the obstinacy of a behavior from which and for which phenomena of various kinds become aesthetically significant. The aesthetic of rationality: Here, Seel refers to the importance that the rationality of aesthetic practice holds or can hold within the ensemble of actions that determine the rationality of a way of life and society. The actual interest of this treatise lies in this second aspect. The question is not to what extent aesthetic behavior is already related to reason - this will be demonstrated.