Dickens understood something that goes beyond mere cheerfulness—he recognized that joy operates like a force of nature, independent of our rational defenses. When we encounter genuine laughter in another person, we're not choosing to catch it the way we might deliberate about adopting their opinion; it bypasses our skepticism entirely. Watch a room when one person begins laughing authentically, and you'll see how quickly faces soften and shoulders drop, as though everyone's nervous system recognizes permission to relax. What makes this observation so penetrating is that Dickens places laughter above persuasion itself—far more effective than argument, sermon, or reason at changing the atmosphere between human beings.