Only the fittest will survive.

As man advances in civilization, and small tribes are united into larger communities, the simplest reason would tell each individual that he ought to extend his social instincts and sympathies to all members of the same nation, though personally unknown to him. This point being once reached, there is only an artificial barrier to prevent his sympathies extending to the men of all nations and races.

I conclude that the musical notes and rhythms were first acquired by the male or female progenitors of mankind for the sake of charming the opposite sex.

I have no great quickness of apprehension or wit which is so remarkable in some clever men, for instance Huxley

That there is much suffering in the world no one disputes. Which is more likely, that pain and evil are the result of an all-powerful and good God, or the product of uncaring natural forces? The presence of much suffering agrees well with the view that all organic beings have been developed through variation and natural selection.

He who understands baboon would do more towards metaphysics than Locke.

Some few, and I am one of them, even wish to God, though at the loss of millions of lives, that the North would proclaim a crusade against slavery. In the long-run, a million horrid deaths would be amply repaid in the cause of humanity. Great God! how I should like to see the greatest curse on earth - slavery - abolished!