Only the unknown frightens men. But once a man has faced the unknown, that terror becomes the known.

The line argues that fear is less about danger itself than about uncertainty. “The unknown” stands for what has not yet been experienced, named, or understood; it becomes frightening precisely because it resists mental rehearsal and control. Once a person confronts it—through action, exposure, or experience—the mind can categorize it, and the raw terror diminishes into something manageable: “the known.” The thought aligns with a broader human pattern in which familiarity reduces anxiety and courage is often the act of converting uncertainty into lived knowledge. It also implies an ethic of engagement: to lessen fear, one must meet what is feared rather than avoid it.