Masse und Machtis a study of human nature and human society in the tradition of Darwinian naturalism that runs, by way of Nietzsche and Freud, down to the sociobiological literature of our own day. “Naturalism” here is not a literary but a philosophical term. It implies the attempt to study human life as part of nature, with the help of the natural sciences, and without reference to any non-natural or supernatural concepts such as divine revelation, a God-given order, or Platonic forms. Darwinian naturalism is a grandiose attempt, in Nietzsche's words, to translate man back into nature, to remove the idealistic scribblings that had disfigured the original text “homo natura.”

Darwin's name provides a convenient label, or emblem, for this project, but he did not initiate it. In the seventeenth century, Thomas Hobbes constructed an anthropology, or an account of humanity, based ultimately on scientific materialism, in which nature usurped the place of God. The Enlightenment tried to devise a more optimistic anthropology, in which man's natural desires and drives were declared good. The theory of evolution set out in The Origin of Species (1859) and explicitly applied to humanity in The Descent of Man (1871), though contested in its time, eventually pulled together many previous explorations of man's place within the natural world and confirmed that man was to be understood not as divinely created but as a special kind of animal. “We no longer derive man from ‘spirit,’ from ‘divinity,’ we have put him back among the animals,” wrote Nietzsche.Once convinced that man had evolved from animals, subsequent thinkers could speculate about how modern social institutions and moral standards had developed from equivalents in human prehistory, and these in turn from analogues to be observed in the social life of animals. Among such speculations, Nietzsche's Zur Genealogie der Moral (1888, The Genealogy of Morals) is a particularly radical attempt to explain how man became an animal that could make and keep promises, distinguish the morally “evil” from the merely “bad,” and develop the ascetic ideals that were the foundation of culture; while Freud in Totem und Tabu (1913, Totem and Taboo, 1919) undertook to derive the institutions of society, art, and religion from the Oedipus complex as supposedly embodied in the social life of early man. Both are indebted to evolutionary thought, though neither Nietzsche nor Freud accepted Darwin's particular version of evolution.