I agree with Agassiz that dogs possess something very like conscience.

Our descent, then, is the origin of our evil passions!! The devil under form of Baboon is our grandfather.

[Herschel and Humboldt] stirred up in me a burning zeal to add even the most humble contribution to the noble structure of Natural Science. No one or a dozen other books influenced me nearly so much as these two. I copied out from Humboldt long passages about Teneriffe and read them aloud on one of [my walking excursions].

I have steadily endeavored to keep my mind free so as to give up any hypothesis, however much beloved (and I cannot resist forming one on every subject), as soon as the facts are shown to be opposed to it.

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.

The fact of evolution is the backbone of biology, and biology is thus in the peculiar position of being a science founded on an improved theory, is it then a science or faith?

Building a better mousetrap merely results in smarter mice.