If numerous species, belonging to the same genera or families, have really started into life all at once, the fact would be fatal to the theory of descent with slow modification through natural selection.

Nothing is easier than to admit in words the truth of the universal struggle for life, or more difficult, at least I have found it so, than constantly to bear this conclusion in mind.

Why is thought being a secretion of brain, more wonderful than gravity a property of matter? It is our arrogance, our admiration of ourselves.

From the first dawn of life, all organic beings are found to resemble each other in descending degrees, so that they can be classed in groups under groups. This classification is evidently not arbitrary like the grouping of stars in constellations.

Man, like every other animal, has no doubt advanced to his present high condition through a struggle for existence consequent on his multiplication; and if he is to advance still higher, it is to be feared that he must remain subject to a severe struggle.

Mere chance ... alone would never account for so habitual and large an amount of difference as that between varieties of the same species.