Not one change of species into another is on record ... we cannot prove that a single species has been changed.

I long to set foot where no man has trod before.

Blushing is the most peculiar and most human of all expressions.

The chief distinction in the intellectual powers of the two sexes is shown by mans attaining to a higher eminence, in whatever he takes up, than the woman. Whether deep thought, reason, or imagination or merely the use of the senses and hands.....We may also infer.....The average mental power in man must be above that of woman.

I cannot anyhow be contented to view this wonderful universe, and especially the nature of man, and to conclude that everything is the result of brute force. I am inclined to look at everything as resulting from designed laws, with the details, whether good or bad, left to the working out of what we call chance. Not that this notion at all satisfies me. I feel most deeply that the whole subject is too profound for the human intellect. A dog might as well speculate on the mind of Newton. Let each man hope and believe what he can.

I have long discovered that geologists never read each other's works, and that the only object in writing a book is a proof of earnestness.

If I had life to live over again, I would give my life to poetry, to music, to literature, and to art to make life richer and happier. In my youth I steeled myself against them and thought them so much waste.