Microcosm and macrocosm
The idea that the human being mirrors the universe, so that what holds for one holds for the other.
Also: as above, so below, little world and great world
In this view, the body is a small cosmos that reflects the large one: the head with the heavens, the heart with the sun, the organs with the planets. Greek philosophers raised the idea, medieval Christian and Islamic writers developed it, and Renaissance physicians such as Paracelsus used it in medicine and alchemy. Hermetic writers summed it up in the phrase as above, so below. It lies behind astrology and many correspondence systems, since a change in one realm is held to be mirrored in the other. Scholars see it as a way of organising knowledge and also as a source of confidence that human action can matter on a cosmic scale.