A fool at forty is a fool indeed

The proverb describes someone who has not learned from their mistakes and continues to behave foolishly. It implies that those who remain stubbornly set in their ways will never change no matter how much life experience they gain over time.

It is especially a warning against not learning from our mistakes and continuing to repeat them. As a fox is not taken twice in the same snare, a person should not repeat his mistakes twice.

The phrase originated in the 17th century, when it was believed that by the age of forty, a person should have acquired enough wisdom and experience to avoid making foolish decisions.