Whatever evil voices may rage, Science, secure among the powers that are eternal, will do her work and be blessed.

True science and true religion are twin sisters, and the separation of either from the other is sure to prove the death of both. Science prospers exactly in proportion as it is religious; and religion flourishes in exact proportion to the scientific depth and firmness of its basis.

Regarded anatomically, the resemblances between the foot of Man and the foot of the Gorilla are far more striking and important than the differences... be the differences between the hand and foot of Man and those of the Gorilla what they may the differences between those of the Gorilla and those of the lower Apes are much greater.

The only question which any wise man can ask himself, and which any honest man will ask himself, is whether a doctrine is true or false.

Living things have no inertia, and tend to no equilibrium.

My experience of the world is that things left to themselves don't get right.

It ought not to be unpleasant to say that which one honestly believes or disbelieves. That it so constantly is painful to do so, is quite enough obstacle to the progress of mankind in that most valuable of all qualities, honesty of word or of deed.