The One

Plotinus taught that there is a supreme, totally transcendent "One", containing no division, multiplicity, or distinction; beyond all categories of being and non-being. His "One" "cannot be any existing thing", nor is it merely the sum of all things (compare the Stoic doctrine of disbelief in non-material existence), but "is prior to all existents". Plotinus identified his "One" with the concept of 'Good' and the principle of 'Beauty'.

His "One" concept encompassed thinker and object. Even the self-contemplating intelligence (the noesis of the nous) must contain duality. "Once you have uttered 'The Good,' add no further thought: by any addition, and in proportion to that addition, you introduce a deficiency." (III.8.11) Plotinus denies sentience, self-awareness or any other action (ergon) to the One (τὸ Ἕν, to En; V.6.6). Rather, if we insist on describing it further, we must call the One a sheer potentiality (dynamis) or without which nothing could exist. (III.8.10) As Plotinus explains in both places and elsewhere (e.g. V.6.3), it is impossible for the One to be Being or a self-aware Creator God. At (V.6.4), Plotinus compared the One to "light", the Divine Intellect/Nous (Νοῦς, Nous; first will towards Good) to the "Sun", and lastly the Soul (Ψυχή, Psyche) to the "Moon" whose light is merely a "derivative conglomeration of light from the 'Sun'". The first light could exist without any celestial body.

The One, being beyond all attributes including being and non-being, is the source of the world—but not through any act of creation, willful or otherwise, since activity cannot be ascribed to the unchangeable, immutable One. Plotinus argues instead that the multiple cannot exist without the simple. The "less perfect" must, of necessity, "emanate", or issue forth, from the "perfect" or "more perfect". Thus, all of "creation" emanates from the One in succeeding stages of lesser and lesser perfection. These stages are not temporally isolated, but occur throughout time as a constant process.

The One is not just an intellectual concept but something that can be experienced, an experience where one goes beyond all multiplicity. Plotinus writes, "We ought not even to say that he will see, but he will be that which he sees, if indeed it is possible any longer to distinguish between seer and seen, and not boldly to affirm that the two are one."

https://en.wikipedia.org/wiki/Plotinus