Charles Darwin — "One day, on looking at an orchid, I was struck with the idea that the structure …"

"I own that I cannot see as plainly as others do, and as I should wish to do, evidence of design and beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade my…"

"As a proof of the admirable power of the mind, I may mention that I have been for some years training my mind to reject the evidence of my senses when they do not square with my preconceived notions."

"It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is most adaptable to change."

"What a book a Devil's Chaplain might write on the clumsy, wasteful, blundering, low, and horridly cruel works of nature!"

"I have steadily endeavoured to keep my mind free so as to give up any hypothesis, however much beloved, as soon as facts are shown to be opposed to it."