When a thing ceases to be a subject of controversy, it ceases to be a subject of interest.

Hazlitt suggests that intellectual and cultural attention is often sustained less by settled truth than by active dispute. A topic becomes “interesting” when it invites argument—when its meaning, value, or implications remain unsettled and people can take sides. Once consensus forms, the emotional and rhetorical energy that controversy supplies dissipates, and the subject can fade into the background of accepted knowledge. The remark also reflects Hazlitt’s broader temperament as a combative essayist and critic: he treats disagreement as a driver of thought, criticism, and public engagement, while implying that unanimity can breed complacency or indifference.