Contrast

"A bird is the swiftest, a tortoise the slowest of animals : the blood of a bird is remarkable for its heat and the briskness with which it circulates, that of a tortoise for its coldness and sluggishness : the respiration of a bird is remarkable for its perfection, that of a tortoise for its imperfection : a bird is most susceptible of hunger and thirst, a tortoise most enduring : a bird is most readily killed, a tortoise most tenacious of life. The Almighty has scarcely created animals whose characters present so complete a contrast."

"Let us leave our old friend in one of those moments of unmixed happiness which, if we seek them, there are ever some, to cheer our transitory existence here. There are dark shadows on the earth, but its lights are stronger in the contrast. (896)"

"To attempt an understanding of Muad'Dib without understanding his mortal enemies, the Harkonnens, is to attempt seeing Truth without knowing Falsehood. It is the attempt to see the Light without knowing Darkness. It cannot be."

"Of several colors, all equally white, that will look whitest which is against the darkest background. And black will look intensest against the whitest background. And red will look most vivid against the yellowest background; and the same is the case with all colours when surrounded by their strongest contrasts."