If you lose the power to laugh, you lose the power to think.

The line links humor to intellectual freedom: laughter signals flexibility, perspective, and the ability to see contradictions without panic. In that sense, losing the capacity to laugh suggests a hardening into dogma—an emotional rigidity that makes it difficult to question assumptions or entertain alternative explanations. The quote also implies that wit and skepticism are allied; humor can puncture pretension and expose weak reasoning. Read this way, Darrow’s sentiment (whether or not the attribution is correct) treats laughter not as frivolity but as a cognitive tool—an antidote to fear, fanaticism, and the solemn certainty that often blocks clear thought.