PART IX

SCIENCE AND MORALITY

I

UTILITARIAN AND INTUITIVE MORALITY

Difficulty of the problem of morality.—Vivisection and anti-vivisection.—Enquiry into the possibility of rational morality.—Utilitarian and intuitive theories of morality.—Insufficiency of these 301

II

MORALITY AND HUMAN NATURE

Attempts to found morality on the laws of human nature.—Kant’s theory of moral obligation.—Some criticisms of the Kantian theory.—Moral conduct must be guided by reason 309

III

INDIVIDUALISM

Individual morality.—History of two brothers brought up in the same circumstances, but whose conduct was quite different.—Late development of the sense of life.—Evolution of sympathy.—The sphere of egoism in moral conduct.—Christian morality.—Morality of Herbert Spencer.—Danger of exalted altruism 316

IV

ORTHOBIOSIS

Human nature must be modified according to an ideal.—Comparison with the modification of the constitution of plants and of animals.—Schlanstedt rye.—Burbank’s plants.—The ideal of orthobiosis.—The immorality of ignorance.—The place of hygiene in the social life.—The place of altruism in moral conduct.—The freedom of the theory of orthobiosis from metaphysics 325

THE PROLONGATION OF LIFE