A lui la foi, a'   elle le doute, a'   elle le fardeau le plus lourd: la femme ne souffre-t-elle pas toujours pour deux? For him, faith; for her, doubt and for her theheavier load: does not the woman always suffer for both?

-Balzac, Honore¤   de
La Recherche de l'absolu.

Doubt is a necessary precondition tomeaningful action. Fear is the great mover in the end.

-Barthelme, Donald
  Sadness,'The Rise of Capitalism'.

To watch a football game is to be in prolonged neurotic doubt as to what you're seeing. It's more like an emergency happening at a distance than a game.

-Barzun,Jacques
Quoted in Colin  Jarman The Guinness Dictionary of Sports Quotations (1990).

True science teaches us to doubt and, in ignorance, to refrain.

-Bernard, Claude
  An Introduction to theStudy of Experimental Medicine, vol.1, ch.1, section 3 (translated by H C Greene).

When in doubt wear red.

-Blass, Bill (William Ralph)
  In news summaries, 31 Dec.

All we have gained then by our unbelief Is a life of doubt diversified by faith, For one of faith diversified by doubt: We called the chess-board white,öwe call it black.

-Browning, Robert
  Men and Women,'Bishop Blougram's  Apology'.

Most true it is, as a wise man teaches us, that 'doubt of anysort cannot be removed except by Action.'Onwhich ground, too, let him who gropes painfully in darkness or in uncertain light, and prays vehemently that the dawn may ripen into day, lay this other precept well to heart, which to me was of invaluable service: 'Do the Duty which lies nearest thee', which thou knowest to be a Duty! Thy second duty will already have become clearer.

-Carlyle,Thomas
^4  Sartor Resartus, bk.2, ch.9.

Like all self-possessed people, he was prey to doubt.

-Chatwin, Bruce
  What  Am I Doing Here,'Heavenly Horses'.

John Grubby, who was short and stout And troubled with religious doubt, Refused about the age of three To sit upon the curate's knee.

-Chesterton, G(ilbert) K(eith)
  'The New Freethinker'.

O make this heart rejoice or ache; Decide this doubt for me; And if it be not broken, breakö And heal it if it be.

-Cowper,William
  Olney Hymns,'The Contrite Heart'.

Pour ce qu'alors je de¤  sirais vaquer seulement a'   la recherche de la ve¤  rite¤ ,  je pensai qu'il fallait que je†rejetasse comme absolument faux tout ce en quoi je pourrais imaginer le moindre doute, afin de voir s'il ne resterait point, apre'  s cela, quelque chose en ma cre¤  ance qui f u" t entie'  rement indubitable. Sincemy present aimwastogivemyself up tothepursuit of truth alone, I thought I must†reject as if absolutely false anything as to which I could imagine the least doubt, in order to see if I should not be left at the end believing something that was absolutely indubitable.

-Descartes, Rene¤
  Discours de la me¤  thode (Discourse on Method), 4th discourse (translated by G E M  Anscombe and Peter Geach).

And new philosophy calls all in doubt, The element of fire is quite put out; The sun is lost, and th'earth, and no man's wit Can well direct him, where to look for it.

-Donne,John
  'An  Anatomy of the World: The First  Anniversary'.

The doubt of future foes exiles my present joy.

-Elizabeth I
c.1568  'The Doubt of Future Foes'.

   For thof ye had as wise a snout on As Shakespeare or Sir Isaac Newton, Your judgement fouk wou'd hae a doubt on, I'll tak myaith, Till they cou'd see ye wi'a suit on O'gude Braid Claith.

-Fergusson, Robert
  'Braid Claith', stanza 9.

Lord, make me an instrument of Your peace. Where there is hatred, let me sow love; Where there is injury, pardon; Where there is doubt, faith; Where there is despair, hope; Where there is darkness, light; Where there is sadness, joy. O divine Master, grant that I may not so much seek To be consoled as to console; To be understood as to understand; To be loved as to love. For it is in giving that we receive; It is in pardoning that we are pardoned; And it is in dying that we are born to eternal life.

-Franklin, Benjamin
Attributed prayer, traditionally known as the'Prayer of St Francis'.

When in DoubtöWash.

-Gallagher, Noel
  Jennie, ch.5, chapter title. Peter, having turned into a cat, is taught the proper etiquette.

When in doubt, shoutöthat's the motto.

-Hardwicke, Sir Cedric
Attributed, repeating advice that was given to him as a young actor.

The greatest obstacle to being heroic is the doubt whether one may not be going to prove one's self a fool; the truest heroism is to resist the doubt; and the profoundest wisdom, to know when it ought to be resisted and when to be obeyed.

-Hawthorne, Nathaniel
  The Blithedale Romance, ch.2.

   When in doubt, win the trick.

-Hoyle, Edmond
A Short Treatise on the Game of  Whist (first published1742, this edn edited by Charles  Jones,1790). This may be an addition by Jones.

Rule1: Be cautious, careful and when in doubt, keep your mouth shut. Rule 2: When tempted to say something, take a deep breath and refer to Rule1.

-Ito, Lance Allan
  In the NewYork Times, 23  Jul.