Man once surrendering his reason, has no remaining guard against absurdities the most monstrous, and like a ship without rudder, is the sport of every wind. With such persons, gullibility, which they call faith, takes the helm from the hand of reason, and the mind becomes a wreck.
Notes from Wikiquote
Reported in: John P. Kaminski, ed., The Quotable Jefferson (2006), p. 94