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.

Ignorance more frequently begets confidence than does knowledge.

I think it inevitably follows, that as new species in the course of time are formed through natural selection, others will become rarer and rarer, and finally extinct. The forms which stand in closest competition with those undergoing modification and improvement will naturally suffer most.

An agnostic would be the more correct description of my state of mind.

When I view all beings not as special creations, but as the lineal descendants of some few beings which lived long before the first bed of the Cambrian system was deposited, they seem to me to become ennobled.

In regard to the amount of difference between the races, we must make some allowance for our nice powers of discrimination gained by a long habit of observing ourselves.

... probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed.