The paper offers an analysis of the aesthetic category to prepon, suitability, from an early antique period to contemporary revitalization of the same notion under the new name - function. The twentieth century architecture is the place of rebirth of the aesthetic category that gave intonation to the concept of beauty in pre - philosophical antique Greece, as well as to the philosophy of Socrates, Plato and Xenophon. Author's main theses are that the architecture is natural and logical birthplace of to prepon, that two main streams in contemporary architecture: organicism and geometrical rationalism have the same key notion in common - function and that suitability, or function as aesthetic category can be treated as a prysm for the central currents in contemporary art.