EnneadsPlotinus

Plotinus takes Plato's metaphysics and drives it further than Plato did. The Enneads, organized by his student Porphyry into six groups of nine treatises, lay out a picture of reality descending from an absolute first principle, the One, through Intellect and Soul, down into the material world.

The One is beyond being, beyond thought, beyond predication. It does not think, because thinking requires a distinction between thinker and thought, and the One admits no distinction. From the One proceeds Intellect (Nous), which contains the Platonic Forms as a unified living system. From Intellect proceeds Soul, which generates and governs the material cosmos. Matter sits at the bottom, almost nothing, a bare receptacle with no positive character of its own.

This procession is not a temporal event. The One does not choose to create; reality overflows from it by necessity, the way light radiates from a source. And the return journey is always available. The human soul can ascend through philosophical contemplation, turning inward from sensation to thought to the direct apprehension of the One. Plotinus reports having achieved this union several times.

The treatises on beauty, on the intellect's self-knowledge, and on the problems of soul-body relation are among the most concentrated pieces of philosophical writing in the ancient world. Augustine, the Christian Neoplatonists, and the entire medieval tradition of mystical theology read the world through categories Plotinus established.