“The more clearly one sees this world; the more one is obliged to pretend it does not exist.”

The Notebooks of Leonardo da Vinci (1883), XIX Philosophical Maxims. Morals. Polemics and Speculations.
Variant: Why does the eye see a thing more clearly in dreams than with the imagination being awake?

2nd Question & Answer Meeting, Brockwood Park, UK (11 September 1971)
1970s

Essay 2, Section 6
On the Genealogy of Morality (1887)
Context: To see others suffer does one good, to make others suffer even more: this is a hard saying but an ancient, mighty, human, all-too-human principle which even the apes might subscribe; for it has been said that in devising bizarre cruelties they anticipate man and are, as it were his "prelude."

Source: Reel to Real: Race, Sex, and Class at the Movies

Volume III, part IV, chapter XVI (1856).
Modern Painters (1843-1860)

The Problem of Anxiety (1925)
1920s

Source: The Lover

Vol. XI, p. 62
Posthumous publications, The Collected Works
Context: I think we must see this very clearly right at the beginning — that if one would solve the everyday problems of existence, whatever they may be, one must first see the wider issues and then come to the detail. After all, the great painter, the great poet is one who sees the whole — who sees all the heavens, the blue skies, the radiant sunset, the tree, the fleeting bird — all at one glance; with one sweep he sees the whole thing. With the artist, the poet, there is an immediate, a direct communion with this whole marvellous world of beauty. Then he begins to paint, to write, to sculpt; he works it out in detail. If you and I could do the same, then we should be able to approach our problems — however contradictory, however conflicting, however disturbing — much more liberally, more wisely, with greater depth and colour, feeling. This is not mere romantic verbalization but actually it is so, and that is what I would like to talk about now and every time we get together. We must capture the whole and not be carried away by the detail, however pressing, immediate, anxious it may be. I think that is where the revolution begins.