It requires wisdom to understand wisdom: the music is nothing if the audience is deaf.
The study of error is not only in the highest degree prophylactic, but it serves as a stimulating introduction to the study of truth.
The radical novelty of modern science lies precisely in the rejection of the belief... that the forces which move the stars and atoms are contingent upon the preferences of the human heart.
Social movements are at once the symptoms and the instruments of progress. Ignore them and statesmanship is irrelevant; fail to use them and it is weak.
What we call a democratic society might be defined for certain purposes as one in which the majority is always prepared to put down a revolutionary minority.