On the theory of natural selection we can clearly understand the full meaning of that old canon in natural history, โNatura non facit saltum.โ This canon, if we look only to the present inhabitants of the world, is not strictly correct, but if we include all those of past times, it must by my theory be strictly true.
Charles DarwinI have rarely read anything which has interested me more, though I have not read as yet more than a quarter of the book proper. From quotations which I had seen, I had a high notion of Aristotle's merits, but I had not the most remote notion what a wonderful man he was. Linnaeus and Cuvier have been my two gods, though in very different ways, but they were mere schoolboys to old Aristotle.
Charles DarwinWe have seen that the senses and intuitions, the various emotions and faculties, such as love, memory, attention and curiosity, imitation, reason, etc., of which man boasts, may be found in an incipient, or even sometimes in a well-developed condition, in the lower animals.
Charles DarwinI always feel as if my books came half out of Lyell's brain... & therefore that when seeing a thing never seen by Lyell, one yet saw it partially through his eyes.
Charles DarwinJealousy was plainly exhibited when I fondled a large doll, and when I weighed his infant sister, he being then 15? months old. Seeing how strong a feeling of jealousy is in dogs, it would probably be exhibited by infants at any earlier age than just specified if they were tried in a fitting manner
Charles Darwin