I am not too sure by H. L. Mencken

Moral certainty is always a sign of cultural inferiority....
All human progress, even in morals, has been the work of men who have
doubted the current moral values, not of men who have whooped them up
and tried to enforce them. The truly civilized man is always skeptical
and tolerant, in this field as in all others.
His culture is based on "I am not too sure."
H. L. Mencken