That there is much suffering in the world no one disputes. Which is more likely, that pain and evil are the result of an all-powerful and good God, or the product of uncaring natural forces? The presence of much suffering agrees well with the view that all organic beings have been developed through variation and natural selection.

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

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.

I can entertain no doubt, after the most deliberate study and dispassionate judgment of which I am capable, that the view which most naturalists entertain, and which I formerly entertained-namely, that each species has been independently created-is erroneous.

On the ordinary view of each species having been independently created, we gain no scientific explanation.

Species of the same genus would occasionally exhibit reversions to lost ancestral characters.