“There are two kinds of light — the glow that illumines, and the glare that obscures.”

Source: Against the Day (2006), p. 65

From a 1900, April 27, , Sixth Series, 2, 1–40 (1901).
Thermodynamics quotes
Context: The beauty and clearness of the dynamical theory, which asserts heat and light to be modes of motion, is at present obscured by two clouds. I. The first came into existence with the undulatory theory of light, and was dealt with by Fresnel and Dr. Thomas Young; it involved the question, how could the earth move through an elastic solid, such as essentially is the luminiferous ether? II. The second is the Maxwell–Boltzmann doctrine regarding the partition of energy.

Memo to The New Yorker (1959); reprinted in New York Times Book Review (4 December 1988)
Letters and interviews

Section 1 : The Meaning of Life
Founding Address (1876), Life and Destiny (1913)
Context: Here are two kinds of light, the light on the hither side of the darkness and the light beyond the darkness. We must press on through the darkness and the terror of it if we would reach the holier light beyond.
We are here — no matter who put us here, or how we came here — to fulfil a task. We cannot afford to go of our own volition until the last item of our duty is discharged.

Source: Good Readshttps://www.goodreads.com/author/quotes/237227.Yvonne_Vera

Our Christ : The Revolt of the Mystical Genius (1921)
Context: In point of fact there are two kinds sorts of mysticism, differing from one another as the ranting of drunkards from the language of illumined spirits. There is the muddled, stammering mysticism, and there is the mysticism luminous with truly ultimate ideas. On the one hand there are the empty dimness and darkness, the barren, chilling sentimentalism and mental debauchery, the foolishly grimacing but rigid phantasms of the Cabbala, of occultism, mysteriosophy and theosophy. We cannot draw too sharp a dividing line between these and the brightness, the simple sincerity, and healthy, rejuvenating strength of genuine mysticism, which takes the most precious gems from philosophy's treasure chest and displays them in the beauty of its own setting. Mysticism is in complete accord with the result, with the sum of philosophy. In fact, mysticism is precisely the sum and the soul of philosophy, in the form of that rapturous, passionate outpouring of love.... We are concerned with an understanding of this serious mysticism, and its meaning could be stated in three words... godlessness... freedom from the world... blessedness of soul.

Source: I Am the Messenger

Gavin Stevens in Ch. 6
The Mansion (1959)

February 26, 1964, page 52.
Official Report of Proceedings of the Hong Kong Legislative Council