“Dark Helmet : So, Lone Star, now you see that evil will always triumph because good is dumb.”

Spaceballs

Academy of Achievement interview (1991)
Context: I judge things from an evolutionary perspective — "How does this serve and contribute to the process of our own evolution?" — rather than think of good and evil in moral terms. I see the triumph of good over evil as a manifestation of the error-correcting process of evolution.

Source: Betrayed

Source: The Age of Innocence

Misattributed
Variant: When its dark enough you can see the stars.

Widely attributed to Ralph Waldo Emerson on the internet; however, a presumably definitive source of Emerson's works at http://www.rwe.org fails to confirm any occurrence of this phrase across his works. This phrase is found in remarks attributed to Charles A. Beard in Arthur H. Secord, "Condensed History Lesson", Readers' Digest, February 1941, p. 20; but the origin has not been determined. Possibly confused with a passage in "Illusions" in which Emerson discusses his experience in the "Star Chamber": "our lamps were taken from us by the guide, and extinguished or put aside, and, on looking upwards, I saw or seemed to see the night heaven thick with stars glimmering more or less brightly over our heads, and even what seemed a comet flaming among them. All the party were touched with astonishment and pleasure. Our musical friends sung with much feeling a pretty song, “The stars are in the quiet sky,” &c., and I sat down on the rocky floor to enjoy the serene picture. Some crystal specks in the black ceiling high overhead, reflecting the light of a half–hid lamp, yielded this magnificent effect."
Misattributed

Variant: Only in the darkness can you see the stars.
Context: But I know, somehow, that only when it is dark enough, can you see the stars.

Source: The Alchemist