Every species has come into existence coincident both in space and time with a pre-existing closely allied species.

I am thankful I can see much to admire in all religions.

What we need are not prohibitory marriage laws, but a reformed society, an educated public opinion which will teach individual duty in these matters

I think I have fairly heard and fairly weighed the evidence on both sides, and I remain an utter disbeliever in almost all that you consider the most sacred truths... I can see much to admire in all religions... But whether there be a God and whatever be His nature; whether we have an immortal soul or not, or whatever may be our state after death, I can have no fear of having to suffer for the study of nature and the search for truth.

I hold with Henry George, that at the back of every great social evil will be found a great political wrong

To the mass of mankind religion of some kind is a necessity

On the spiritual theory, man consists essentially of a spiritual nature or mind intimately associated with a spiritual body or soul, both of which are developed in and by means of a material organism