This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Plotinus considered himself a faithful interpreter of Plato, not an innovator, and the claim is stranger than it sounds, because the system he built out of Plato's dialogues, worked out in Rome from around 244 CE onward and preserved by his student Porphyry in the six sets of nine treatises called the Enneads, pushes one line of Platonic thought to a conclusion Plato himself never quite stated. In the Republic, Plato describes the Form of the Good as beyond being itself, the source of the reality and knowability of every other Form the way the sun is the source of the visibility of every other visible thing, without itself being simply one visible thing among others. Plotinus took that single, difficult phrase and built an entire metaphysics on it. His first principle, the One, is not a being, not even the highest being, because being already implies some determinate character, and the One is prior to every determination, utterly simple, beyond description, beyond even the categories that language and logic can reach. Everything else exists by a kind of overflow from this absolute source, emanation rather than creation, first Intellect, the realm where the Platonic Forms exist as a unified, self-thinking whole, then Soul, which mediates between the unified intelligible world and the divided, changing world of matter, organizing and animating it without being reducible to it. Descent from the One is not a fall in the way later Gnostic systems, which Plotinus wrote directly against, treated the material world as an evil produced by an inferior or fallen power, matter for Plotinus is simply the furthest, faintest point of the One's own outward radiance, good in its own limited way rather than evil. The system is austere and demanding, and it is also, Plotinus insisted, a description of a real path: philosophy, on his account, is not only an intellectual exercise but an ascent, a turning of the soul back toward the One it emanated from, which is why later readers, Christian, Islamic and Jewish alike, found in Plotinus a metaphysics that could be adapted to describe the soul's return to God.