Persevere, and, don't let any self-doubt distract you.
Catherine Pulsifer
A castle called Doubting Castle, the owner whereof was Giant Despair.
John Bunyan
People may doubt what you say but they will believe what you do.
Unknown
Laugh at yourself, but don't ever aim your doubt at yourself.
Alan Alda
I respect faith, but doubt is what gets you an education.
Wilson Mizner
Knowledge is gained by learning; trust by doubt; skill by practice; love by love.
Thomas Szasz
As to the Adjective: when in doubt, strike it out.
Mark Twain
Faith and doubt both are needed -- not as antagonists, but working side by side -- to take us around the unknown curve.
Lillian Smith
To deny, to believe, and to doubt absolutely -- this is for man what running is for a horse.
Blaise Pascal
Doubt is part of all religion. All the religious thinkers were doubters.
Isaac Bashevis Singer
To have doubted one's own first principles is the mark of a civilized man.
Oliver Wendell Holmes