The older I grow the more I distrust the familiar doctrine that age brings wisdom.

Mencken turns the proverb “with age comes wisdom” on its head, using his own aging as evidence against it. The line suggests that experience does not automatically refine judgment; it can just as easily harden prejudices, deepen cynicism, or reveal how persistent human folly is. The phrasing “familiar doctrine” implies a culturally comforting belief that Mencken—characteristically skeptical of pieties and received ideas—finds increasingly unconvincing. Read as social criticism, the remark also challenges deference to elders or tradition: authority grounded merely in longevity is suspect, and wisdom must be demonstrated rather than presumed.