When in doubt, do it.

To have doubted one's own first principles, is the mark of a civilized man.

To have doubted one's own first principles is the mark of a civilized man.

The degree of civilization which a people has reached, no doubt, is marked by their anxiety to do as they would be done by

When in doubt, do it.

I think that, as life is action and passion, it is required of a man that he should share the passion and action of his time at peril of being judged not to have lived.