As for a future life, every man must judge for himself between conflicting vague probabilities.

The expression often used by Mr. Herbert Spencer of the Survival of the Fittest is more accurate, and is sometimes equally convenient.

Multiply, vary, let the strongest live and the weakest die.

I am quite conscious that my speculations run beyond the bounds of true science....It is a mere rag of an hypothesis with as many flaw[s] & holes as sound parts.

Nature will tell you a direct lie if she can.

Looking to future generations, there is no cause to fear that the social instincts will grow weaker... the social instincts, - the prime principle of man's moral constitution - with the aid of active intellectual powers and the effects of habit, naturally lead to the golden rule, "As ye would that men should do to you; do ye to them likewise"; and this lies at the foundation of morality.

It is well-known that those who have charge of young infants, that it is difficult to feel sure when certain movements about their mouths are really expressive; that is when they really smile. Hence I carefully watched my own infants. One of them at the age of forty-five days, and being in a happy frame of mind, smiled... I observed the same thing on the following day: but on the third day the child was not quite well and there was no trace of a smile, and this renders it probable that the previous smiles were real.