Beauty makes idiots sad and wise men merry.

Nathan’s aphorism turns on a contrast in how different temperaments metabolize beauty. For the “idiot,” beauty provokes sadness—envy, inadequacy, or the sense of exclusion that can accompany encounters with excellence or grace. For the “wise,” beauty produces merriment: not shallow amusement, but a buoyant, enlarging pleasure in the world’s richness. The line also reflects Nathan’s characteristic epigrammatic cynicism: beauty is not morally improving by itself; it amplifies what is already present in the observer—resentment in the small-minded, delight in the discerning. In that sense, the quote is less about beauty than about the psychology of perception.