In the seventeenth century, at the same time that classical physics gave renewed emphasis to atomism and reductionism, Spinoza developed a holistic philosophy reminiscent of Parmenides. According to Spinoza, all the differences and apparent divisions we see in the world are really only aspects of an underlying single substance, which he called God or nature. Based on pantheistic religious experience, this emphasis on an underlying unity is reflected in the mystical thinking of most major spiritual traditions. It also reflects developments in modern quantum field theory, which describes all existence as an excitation of the underlying quantum vacuum, as though all existing things were like ripples on a universal pond. Hegel, too, had mystical visions of the unity of all things, on which he based his own holistic philosophy of nature and the state.
Nature consists of one timeless, unified, rational and spiritual reality.
Against individualism, all emphasize the social whole or social forces that somehow possess a character and have a will of their own, over and above the characters and wills of individual members. The twentieth century has seen a tentative movement toward hoilism in such diverse areas as politics, social thinking, psychology, management theory, and medicine. These have included the practical application of Marx's thinking in Communist and Socialist states, experiments in collective living, the rise of Gestalt psychology, systems theory, and concern with the whole person in alternative medicine. All these have been reactions against excessive individualism with its attendant alienation and fragmentation, and exhibit a commonsense appreciation of human beings' interdependency with one another and with the environment. Where atomism was apparently legitimized by the sweeping sucesses of classical physics, holism found no such foundation in the hard sciences.