Knowledge fills a large brain it merely inflates a small one.

Harris contrasts two kinds of minds: the “large brain,” which can absorb knowledge without losing proportion, and the “small one,” which turns learning into vanity. The point is less about intelligence than about intellectual character—humility, breadth, and the ability to integrate facts into judgment. Knowledge, in this view, should deepen understanding and enlarge perspective; when it merely “inflates,” it becomes a badge of superiority, producing pedantry and self-importance rather than wisdom. The aphorism fits Harris’s recurring theme that education and information are morally neutral until shaped by temperament and values.