In the framework of Greek myth, Muses represent a very specific divine power, without a proper analogy in other known mythological systems. Their birth crowns the process of cosmogony, bringing the world into the manifestation: the song of the Muses celebrates the world-order and makes it explicit through its articulation by means of the speech. The world as a whole thus enters the domain of appearance and new cosmological categories emerge. The first one being the beauty of the cosmos: as a world-order as well as the ordered whole, it can now manifest itself as beautiful. The second one being the possibility of fiction, of a delusive appearance: the complex reality can manifest itself in many incompatible ways, partial and thus potentially misleading. The third one being the reflexivity of the cosmos, founded on the reflexivity of the musical speech itself. The Muses are capable to manifest themselves, and even their own manifestation. By means of their song, the world becomes manifest to itself, too. The complex system of divine powers gains a reflexive character, as we try to demonstrate in the course of Hesiod’s Theogony, as well as of the Homeric Hymn to Hermes. In its last part, the paper examines the reflexivity in the domain of the mortals. There it is closely linked with the activity of the poets who interpret the song of the Muses, for it becomes accessible to humans. As an example, we try to trace the theme of reflexivity in the course of Homer’s Odyssey.