Enthusiasm moves the world.

It has always been desirable to tell the truth, but seldom if ever necessary.

Every human soul is of infinite value, eternal, free; no human being, therefore, is so placed as not to have within his reach, in himself and others, objects adequate to infinite endeavor.

But science is the great instrument of social change, all the greater because its object is not change but knowledge, and its silent appropriation of this dominant function, amid the din of political and religious strife, is the most vital of all the revolutions which have marked the development of modern civilisation.

Science preceded the theory of science, and is independent of it. Science preceded naturalism, and will survive it.

Biography should be written by an acute enemy.

In politics nothing matters very much, and few things matter at all.