ignis fatuus quotes

Reason, an ignis fatuus in the mind, Which leaving light of nature, sense behind, Pathless and dangerous wandering ways it takes, Through error's fenny bogs and thorny brakes; Whilst the misguided follower climbs, with pain, Mountains of whimsy heaped in his own brain.

-JohnWilmot, 2nd Earl of Rochester
  'A SatyrAgainst Mankind', l.12^17 (published1679).