'Tis better to be silent and be thought a fool, than to speak and remove all doubt.
Abraham Lincoln
A doubtful friend is worse than a certain enemy. Let a man be one thing or the other, and we then know how to meet him.
Aesop
True wisdom is less presuming than folly. The wise man doubteth often, and changeth his mind the fool is obstinate, and doubteth not he knoweth all things but his own ignorance.
Akhenaton
Laugh at yourself, but don't ever aim your doubt at yourself. Be bold. When you embark for strange places, don't leave any of yourself safely on shore. Have the nerve to go into unexplored territory.
Alan Alda
Doubt 'til thou canst doubt no more...doubt is thought and thought is life. Systems which end doubt are devices for drugging thought.
Albert Guerard
A man desires praise that he may be reassured, that he may be quit of his doubting of himself he is indifferent to applause when he is confident of success.
Alec Waugh
Existence, as we know it, is full of sorrow. To mention only one minor point every man is a condemned criminal, only he does not know the date of his execution. This is unpleasant for every man. Consequently every man does everything possible to postpone the date, and would sacrifice anything that he has if he could reverse the sentence. Practically all religions and all philosophies have started thus crudely, by promising their adherents some such reward as immortality. No religion has failed hitherto by not promising enough the present breaking up of all religions is due to the fact that people have asked to see the securities. Men have even renounced the important material advantages which a well-organized religion may confer upon a State, rather than acquiesce in fraud or falsehood, or even in any system which, if not proved guilty, is at least unable to demonstrate its innocence. Being more or less bankrupt, the best thing that we can do is to attack the problem afresh without preconceived ideas. Let us begin by doubting every statement. Let us find a way of subjecting every statement to the test of experiment. Is there any truth at all in the claims of various religions Let us examine the question.
Aleister Crowley
There are two ways to slide easily through life to believe everything or to doubt everything. Both ways save us from thinking.
Alfred Korzybski
There lives more faith in honest doubt, believe me, than in half the creeds.
Alfred Lord Tennyson
Cleave never to the sunnier side of doubt.
Alfred Lord Tennyson