"On the spiritual theory, man consists essentially of a spiritual nature or mind intimately associate..." — Alfred Russel Wallace

Truth is born into this world only with pangs and tribulations, and every fresh truth is received unwillingly.

To expect the world to receive a new truth, or even an old truth, without challenging it, is to look for one of those miracles which do not occur.

I am decidedly of the opinion that in very many instances we can trace such a necessary connexion, especially among birds, and often with more complete success than in the case which I have here attempted to explain.

Civilisation has ever accompanied emigration and conquest - the conflict of opinion, of religion, or of race.