PLOTINUS (204/5 - 270 CE)

From Plotinus's Eneeads

Behind the variegated multiplicity of the visible world there is an ultimate unitary source, "The One" (Greek: to hen), which is beyond experience and empirical knowledge

The concept of Beauty relies on the notion of The One

Eneead 1, Tractate 6, chapter 1

What...is it that gives comeliness to material forms and draws the ear to the sweetness perceived in sounds, and what is the secret of the beauty there is in all that derives from Soul? Is there some One Principle from which all take their grace...? ... Almost everyone declares that the symmetry of parts towards each other and towards a whole ... constitutes the beauty recognized by the eye ... as indeed in all else, universally, the beautiful thing is essentially symmetrical, patterned. ... Only a compound can be beautiful, never anything devoid of parts; and only a whole; the several parts will have beauty, not in themselves, but only as working together to give a comely total.

Eneead 1, Tractate 6, chapter 2

All shapelessness whose kind admits of pattern and form, as long as it remains outside of Reason and Idea, is ugly by the very isolation from the Divine-Thought...an ugly thing is something that has not been entirely mastered by pattern, that is, by Reason, the Matter not yielding at all points and in all respects to Ideal-Form. But where the Ideal-Form has entered, it has grouped and coordinated what from a diversity of parts was to become a unity: it has rallied confusion into cooperation; it has made the sum one harmonious coherence: for the Idea as a unity and what it molds must come to unity as far as multiplicity may. And on what has thus been compacted to unity, Beauty enthrones itself, giving itself to the parts as to the sum...This, then, is how the material thing becomes beautiful‑‑by communicating in the thought that flows from the divine.

Beauty is the "outcome of unification" (I:6:3)

On perception of beauty:

Eneead 1, Tractate 6, chapter 3

So with the perceptive faculty: discerning in certain objects the Ideal-From which has bound and controlled shapeless matter...it gathers into unity what still remains fragmentary...and presents it to the Ideal-Principle as something concordant and congenial... ... And the harmonies unheard in sound create the harmonies we hear and wake the soul to the consciousness of beauty, showing it the one essence in another kind; for the measures of our sensible music are not arbitrary but are determined by the Principle whose labor is to dominate Matter and bring pattern into being.