With highly civilised nations continued progress depends in a subordinate degree on natural selection; for such nations do not supplant and exterminate one another as do savage tribes.

The most energetic workers I have encountered in my world travels are the vegetarian miners of Chile.

Nothing exists for itself alone, but only in relation to other forms of life

If I had my life to live over again, I would have made a rule to read some poetry and listen to some music at least once every week.

Although I am fully convinced of the truth of the views given in this volume under the form of an abstract, I by no means expect to convince experienced naturalists whose minds are stocked with a multitude of facts all viewed, during a long course of years, from a point of view directly opposite to mine... I look with confidence to the future, to young and rising naturalists, who will be able to view both sides of the question with impartiality.

There is no fundamental difference between humans and the higher mammalsin their mental faculties

The western nations of Europe, who now so immeasurably surpass their former savage progenitors, and stand at the summit of civilization, owe little or none of their superiority to direct inheritance from the old Greeks, though they owe much to the written works of that wonderful people.