"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."

"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."

"If a man were to read a book on the cultivation of fruit trees, and then attempt to practice it without having seen a single tree, he would not be more unsuccessful than those who attempt to philosoph…"

"The love of experiment and the patient observation of nature are the two great qualifications for a naturalist."

"The fact that I can't remember anything from the first three years of my life is no proof that I wasn't an embryo then."