I was a young man with uninformed ideas. I threw out queries, suggestions, wondering all the time over everything; and to my astonishment the ideas took like wildfire. People made a religion of them.

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.

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.

Man scans with scrupulous care the character and pedigree of his horses, cattle, and dogs before he matches them; but when he comes to his own marriage he rarely, or never, takes any such care.

The main conclusion here arrived at ... is that man is descended from some less highly organized form.

[Alexander von Humboldt was the] greatest scientific traveller who ever lived.

I see no good reasons why the views given in this volume should shock the religious views of anyone.