True intelligence very readily conceives of an intelligence superior to its own; and this is why truly intelligent men are modest.

Gide links intellectual clarity with humility: a genuinely intelligent person can easily imagine minds more capable than their own, and that imaginative reach prevents complacency. Modesty here is not self-deprecation but an epistemic attitude—an awareness of the vastness of what one does not know and of the plausible existence of superior judgment. The remark also implies a critique of pretension: those who boast of their intelligence may do so because their mental horizon is narrow, making it harder for them to conceive of greater intelligence. In this sense, humility becomes a sign of intellectual maturity and openness rather than weakness.