To understand everything makes one tolerant.

The aphorism links intellectual and moral virtues: the more fully one grasps the causes, pressures, and histories behind people’s actions, the less room there is for reflexive condemnation. “Understand everything” does not mean excusing everything; rather, it suggests that comprehension enlarges sympathy and moderates judgment. In de Staël’s liberal, cosmopolitan spirit, tolerance is portrayed as an achievement of imagination and analysis—an ability to see complexity where prejudice prefers simple blame. The line also implies a practical ethic: if you want a more tolerant society, cultivate habits of inquiry, context, and perspective-taking, because intolerance often thrives on ignorance and oversimplification.

“Tout comprendre, c’est tout pardonner.”
“Tout comprendre, c’est tout tolérer.”