Plotinus said all of reality overflows from one indescribable source

Plotinus argued that everything which exists emanates in descending stages from a perfectly simple, unified source he called "the One" — a cause beyond being and thought itself, the way light radiates from the sun without diminishing it. Intellect flows from the One, Soul flows from Intellect, and the physical world unfolds from there. A soul's task, he wrote, is to strip away multiplicity and return to that source.

— Plotinus, The Enneads — Compiled and edited by Porphyry, c. 270 CE
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