The human being as microcosm, a small world reflecting the macrocosm, is an idea found in Plato’s Timaeus, the Stoics, the Hermetic writings, Islamic philosophy, Kabbalah and the Renaissance. It grounds the conviction that self-knowledge is knowledge of the universe.
Microcosm
The little world: the idea that the human being mirrors the whole cosmos.
Also: microcosm and macrocosm