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

It has been generally the custom of writers on natural history to take the habits and instincts of animals as the fixed point, and to consider their structure and organization as specially adapted to be in accordance with them.

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

To say that mind is a product or function of protoplasm, or of its molecular changes, is to use words to which we can attach no clear conception

In my solitude I have pondered much on the incomprehensible subjects of space, eternity, life and death.

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.

As well might it be said that, because we are ignorant of the laws by which metals are produced and trees developed, we cannot know anything of the origin of steamships and railways