Criticism is necessary and useful; it is often indispensable; but it can never take the place of action, or be even a poor substitute for it. The function of the mere critic is of very subordinate usefulness. It is the doer of deeds who actually counts in the battle for life, and not the man who looks on and says how the fight ought to be fought, without himself sharing the stress and the danger.

The Works of Theodore Roosevelt: American ideals, with a biographical sketch by F. V. Greene. Administration (ed. 1897)