The Greek term for intellect, mind, or divine intelligence, nous (νοῦς) occupies a central position in ancient philosophy and becomes the second hypostasis in Neoplatonism - the first emanation from The One and the realm where Forms or Ideas exist as living, luminous realities. Unlike discursive reasoning (dianoia), which proceeds step by step through argument, nous apprehends truth immediately and whole, in a single intuitive grasp.
In Aristotle, nous names the highest capacity of the soul - that which contemplates eternal truths and, in its active form (nous poietikos), may be divine and immortal. Anaxagoras had earlier proposed nous as the cosmic ordering principle that initiated motion and separated the primordial mixture into distinct things. But it was Plotinus who gave nous its fullest metaphysical elaboration: the first outpouring from the One, nous eternally contemplates its source while simultaneously generating the multiplicity of Forms within itself. It is both thinker and thought, knower and known - a unity-in-diversity that contains all intelligible reality.
For the Neoplatonists, nous represents the level at which the undifferentiated unity of the One first becomes articulated into distinct Ideas - Beauty, Justice, the Good, and all the Platonic Forms. The human mind participates in nous when it engages in genuine contemplation; philosophical anamnesis is precisely the soul’s turning toward the intelligible realm it once knew directly. To think truly is to touch something divine - to participate in the eternal self-thinking thought that Aristotle called “thought thinking itself.”
See also The One, Psyche, Emanation & Descent, intelligible realm, Plotinus, intellect, divine mind.