Cosmogony, a theory of the origin of the universe (Gr. kosmos) and its inhabitants, such as is found in the mythologies of all peoples except those in the very lowest stages of culture. There is the utmost variety in the explanations given, the only idea that is at all widely spread being that in the beginning all things were held in solution by water. Other prevailing conceptions are those of the Phœnician and Egyptian generative world-egg; of the Hindu tortoise which supports elephants, themselves the actual bearers of the world; of the Polynesian air-god, Tangaloa, hovering over the waters. A very elaborate cosmogony is given in the Pehlevi Bundehesh, ascribing creation to the free-will of a personal deity, as distinct from primordial matter, and this more elevated conception the religion of Zoroaster shares with the Jewish alone.
In the Sanchoniathon we have presented in a Greek version a fragment of an interesting Phœnician cosmogony, which explains the origin of organic matter as due to a series of spontaneous emanations. But the most interesting cosmogonies we possess are the ancient Babylonian, of which one form is preserved in the Greek of Berossus, while another was deciphered by George Smith from the cuneiform inscriptions. These present startling identities with the creation story in the first chapter of Genesis.
Modern cosmogonists arrange themselves mainly according to their attitude to Theism (q.v.). Theists explain the world of matter and order as having come into existence at the omnifiat. Pantheism (q.v.), again, holds the universe to be the very body and being of Deity, and as such to have been from all eternity. Most men of science, in modern times, stopping short of an actual cosmogony or genesis of the world, have pushed their inquiries into the order of development of its present state. Some assume the necessary existence of matter; with these there is no proper beginning of things, but an eternal round, under fixed laws of growth and decay.
In cosmogonical speculations, heat, air, atoms with rotatory motions, numbers—have all in turn been recognised as the fountain and causes of things. Of hypotheses as to the formation of our own rotating globe, of our system, and of all similar systems in space, the most notable is that of Laplace, founded on observation of the mutual relations of the planets, their common direction in rotation and revolution, their general conformity to one plane, &c., taken in connection with such facts as the rings of Saturn and the fundamental unity of the asteroids. Laplace had in some measure been anticipated by Kant. Thus arose the Nebular Theory (q.v.), the evidence for which was carefully marshalled by Sir William Herschel; and which is still regarded by some physicists as indicated by the general tendencies of the laws of nature. M. Faye has given his theory of the origin of the earth from meteorites, and discussed other cosmogonic theories in Sur l'Origine du Monde (1880). Following up this view of a formation of the planetary globes by natural causes, there have been speculations as to the commencement and progress of organic life upon them, and communication of it from one planet to another (as by Sir William Thomson; and see Professor Tyndall's presidential address to the British Association in 1874). Darwin's work has completely altered the face of biological research and theory (see EVOLUTION, DARWINIAN THEORY, SPENCER). For the cosmogonies of the various nations, philosophies, and religions, see MATERIALISM, THEOGONY, HEGEL, ADAM, CREATION; as also the articles on the Scandinavian Mythology, on the Greek Religion, on Spontaneous Generation, and on various aspects of Indian speculation.