“What is beautiful is moral, that is all there is to it.”

Source: Seriously... I'm Kidding

Trattato Terzo, Ch. 15.
Il Convivio (1304–1307)

June 21, 1852
Journals (1838-1859)

Source: Don John (1881), Ch. 36, p. 382.

in Greek: "Όμορφος κόσμος, ηθικός, αγγελικά πλασμένος".
Sarcastic tone; from his poem "to Francesca Freiser"

in Greek: "Όμορφος κόσμος, ηθικός, αγγελικά πλασμένος".
Sarcastic tone; from his poem "to Francesca Freiser"

Evanescence (1900).

The Eye of Spirit : An Integral Vision for a World Gone Slightly Mad (1997)
Context: The integral vision, I believe, is more than happy to welcome empirical science as a part — a very important part — of the endeavor to befriend the Kosmos, to be attuned to its many moods and flavors and facets and forms. But a more integral psychology goes beyond that... With science we touch the True, the "It" of Spirit. With morals we touch the Good, the "We" of Spirit. What, then, would an integral approach have to say about the Beautiful, the "I" of Spirit itself? What is the Beauty that is in the eye of the Beholder? When we are in the eye of Spirit, the I of Spirit, what do we finally see?

Introduction to Book 1, as quoted/translated by Edward Rosen, Nicholas Copernicus on the Revolutions (1978) ed. Jerzy Dobrzycki, Edward Rosen.
De revolutionibus orbium coelestium (1543)