“Countless attempts have been made to no avail to construct a continuity from the supreme principle of the intellectual world to the finite world. The oldest and most frequent of these attempts is well known: the principle of emanation, according to which the outflowings from the godhead, in gradual increments and detachment from the ordinary source, losing their divine perfection until, in the end, they pass into the opposite (matter, privation), just as light is finally confined by darkness. P. 24”

Source: Nietzsche: Life as Literature (1985), pp. 33-34.

Students' Text-book of Color; Or, Modern Chromatics, with Applications to Art and Industry. New York: D. Appleton and Company. 1881.

Source: De architectura (The Ten Books On Architecture) (~ 15BC), Book I, Chapter II, Sec. 5

Mutual Aid: A Factor of Evolution (1902)
Context: It is especially in the domain of ethics that the dominating importance of the mutual-aid principle appears in full. That mutual aid is the real foundation of our ethical conceptions seems evident enough. But whatever the opinions as to the first origin of the mutual-aid feeling or instinct may be whether a biological or a supernatural cause is ascribed to it — we must trace its existence as far back as to the lowest stages of the animal world; and from these stages we can follow its uninterrupted evolution, in opposition to a number of contrary agencies, through all degrees of human development, up to the present times. Even the new religions which were born from time to time — always at epochs when the mutual-aid principle was falling into decay in the theocracies and despotic States of the East, or at the decline of the Roman Empire — even the new religions have only reaffirmed that same principle. They found their first supporters among the humble, in the lowest, downtrodden layers of society, where the mutual-aid principle is the necessary foundation of every-day life; and the new forms of union which were introduced in the earliest Buddhist and Christian communities, in the Moravian brotherhoods and so on, took the character of a return to the best aspects of mutual aid in early tribal life.
Each time, however, that an attempt to return to this old principle was made, its fundamental idea itself was widened. From the clan it was extended to the stem, to the federation of stems, to the nation, and finally — in ideal, at least — to the whole of mankind.

Source: Initiation Into Hermetics (1956), p. 28

can be compared with experience
Die partiellen Differentialgleichungen der mathematischen Physik (1882) as quoted by Robert Édouard Moritz, Memorabilia Mathematica; Or, The Philomath's Quotation-book https://books.google.com/books?id=G0wtAAAAYAAJ (1914) p. 239

Source: The Brain As A Computer (1962), p.1

Light
Source: I am That, P.197.

The Book of Delusions (1936)