Intelligence is based on how efficient a species became at doing the things they need to survive.

The love for all living creatures is the most noble attribute of man.

The age-old and noble thought of 'I will lay down my life to save another,' is nothing more than cowardice.

How fleeting are the wishes and efforts of man! how short his time! and consequently how poor will his products be, compared with those accumulated by nature during whole geological periods. Can we wonder, then, that nature's productions should be far 'truer' in character than man's productions; that they should be infinitely better adapted to the most complex conditions of life, and should plainly bear the stamp of far higher workmanship?

If man had not been his own classifier, he would never have thought of founding a separate order for his own reception.

Why, if species have descended from other species by insensibly fine gradations, do we not everywhere see innumerable transitional forms.

I 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.