Pessimism is only the name that men of weak nerves give to wisdom.

The line draws a sharp distinction between clear-eyed judgment and the emotional label “pessimism.” De Voto suggests that what some people dismiss as gloomy negativity is often simply sober recognition of reality—“wisdom” that refuses comforting illusions. Calling it “the name that men of weak nerves give” implies that the charge of pessimism can be a defensive reaction: those who cannot tolerate hard truths rebrand them as defeatism. The aphorism also hints at a moral posture: intellectual courage consists in facing unpleasant facts without flinching, while “weak nerves” seek reassurance rather than understanding.