Owing to this struggle for life, any variation, however slight and from whatever cause proceeding, if it be in any degree profitable to an individual of any species, in its infinitely complex relationship to other organic beings and to external nature, will tend to the preservation of that individual, and will generally be inherited by its offspring.
Charles DarwinWhy, if species have descended from other species by insensibly fine gradations, do we not everywhere see innumerable transitional forms.
Charles DarwinWho when examining in the cabinet of the entomologist the gay and exotic butterflies, and singular cicadas, will associate with these lifeless objects, the ceaseless harsh music of the latter, and the lazy flight of the former - the sure accompaniments of the still, glowing noonday of the tropics.
Charles DarwinMr. J.S. Mill speaks, in his celebrated work, "Utilitarianism," of the social feelings as a "powerful natural sentiment," and as "the natural basis of sentiment for utilitarian morality," but on the previous page he says, "if, as is my own belief, the moral feelings are not innate, but acquired, they are not for that reason less natural." It is with hesitation that I venture to differ from so profound a thinker, but it can hardly be disputed that the social feelings are instinctive or innate in the lower animals; and why should they not be so in man?
Charles Darwin