Related:

• He who lives without folly is less wise than he believes.
• Ignorance is preferable to error, and he is less remote from the truth who believes nothing, than he who believes what is wrong.
  -- Thomas Jefferson, Notes on the State of Virginia...
• If A fool persists in his folly he shall become wise. -- William Blake
• The truly generous is the truly wise; And he loves not others, lives unblest. -- Horace
• If a fool would persist in his folly he would become wise. -- William Blake
• Answer a fool according to his folly, lest he be wise in his own conceit. -- Proverbs, 26:5
• Love may laugh at locksmiths, but he has a profound respect for money bags.
  -- Sidney Paternoster, "The Folly of the Wise...
• The man who believes he can do it is probably right. -- Helvetiu
• He lives by rule who lives himself to please. -- Crabbe