The Ouroboros often represents self-reflexivity or cyclicality, especially in the sense of something constantly re-creating itself, the eternal return, and other things perceived as cycles that begin anew as soon as they end (compare with phoenix). It can also represent the idea of primordial unity related to something existing in or persisting from the beginning with such force or qualities it cannot be extinguished. The Ouroboros has been important in religious and mythological symbolism, but has also been frequently used in alchemicalillustrations, where it symbolizes the circular nature of the alchemist's opus. It is also often associated with Gnosticism, and Hermeticism. Carl Jung interpreted the Ouroboros as having an archetypal significance to the human psyche. The Jungian psychologist Erich Neumann writes of it as a representation of the pre-ego "dawn state", depicting the undifferentiated infancy experience of both mankind and the individual child.
Plato described a self-eating, circular being as the first living thing in the universe—an immortal, mythologically constructed entity.
- The living being had no need of eyes because there was nothing outside of him to be seen; nor of ears because there was nothing to be heard; and there was no surrounding atmosphere to be breathed; nor would there have been any use of organs by the help of which he might receive his food or get rid of what he had already digested, since there was nothing which went from him or came into him: for there was nothing beside him. Of design he created thus; his own waste providing his own food, and all that he did or suffered taking place in and by himself. For the Creator conceived that a being which was self-sufficient would be far more excellent than one which lacked anything; and, as he had no need to take anything or defend himself against any one, the Creator did not think it necessary to bestow upon him hands: nor had he any need of feet, nor of the whole apparatus of walking; but the movement suited to his spherical form which was designed by him, being of all the seven that which is most appropriate to mind and intelligence; and he was made to move in the same manner and on the same spot, within his own limits revolving in a circle. All the other six motions were taken away from him, and he was made not to partake of their deviations. And as this circular movement required no feet, the universe was created without legs and without feet.
All things began in order so shall they end, so shall they begin again according to the Ordainer of Order and the mystical mathematicks of the City of Heaven.
The god Quetzalcoatl is sometimes portrayed biting its tail on Aztec and Toltec ruins. A looping Quetzalcoatl is carved into the base of the Pyramid of the Feathered Serpent, at Xochicalco, Mexico, 700-900 A.D.