The more uncertain I have felt about myself, the more there has grown up in me a feeling of kinship with all things.
Men become civilized not in proportion to their willingness to believe, but in proportion to their willingness to doubt.
Doubts are more cruel than the worst of truths.
Four be the things I’d been better without: Love, curiosity, Freckles and doubt.
Our doubts are traitors and cause us to miss the good we oft might win by fearing to attempt.
Among the safe courses, the safest of all is to doubt.
Seeking to know is only too often learning to doubt.
The believer is happy; the doubter is wise.
Doubts and jealousies often beget the facts they fear.
Weary the path that does not challenge. Doubt is an incentive to truth and patient inquiry leadeth the way.