It was great fun writing a book.... It built an impalpable crystal sphere around one of interests and ideas. In a sense one felt like a goldfish in a bowl; but in this case the goldfish made his own bowl. This came along everywhere with me. It never got knocked about in travelling, and there was never a moment when agreeable occupation was lacking. Either the glass had to be polished, or the structure extended or contracted, or the walls required strengthening.

Don't join the book burners. Don't think you are going to conceal faults by concealing evidence that they ever existed.

Natural selection rendered evolution scientifically intelligible: it was this more than anything else which convinced professional biologists like Sir Joseph Hooker, T. H. Huxley and Ernst Haeckel.

Man in his arrogance thinks himself a great work, worthy of the interposition of a deity. More humble, and I believe truer, to consider him created from animals.

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

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.