COSMOLOGY means a theory of the world or of the world order. The term "cosmos" is mostly used in the sense of an or derly world, or a world-order, in contrast with chaos or disorder. Sometimes the expression cosmology is used as a variant for cosmogony (q.v.) to denote an account of the origin of the world or of its. development out of an original chaos. It is more usual, however, to restrict the term cosmogony to early mytho logical accounts, which are of anthropological or historical in terest, rather than of scientific or philosophical value. "Cos mology," on the other hand, is applied more extensively to any kind of rational attempt to deal with the ultimate problems of Nature. It includes such attempts as that of Descartes to show how an orderly world like ours might have evolved out of an original chaotic collocation of matter and motion, such specula tions as those of Herschel, Kant and Laplace about the origin of the solar system (see NEBULAR THEORY), and more generally all that is usually included under the name of philosophy of Nature (as distinguished from natural philosophy, which is only another name for physics). The extravagances of Schelling (q.v.) in the early part of the i9th century tended to discredit the philosophy of Nature by trespassing rashly on the domain of physics. Cosmological speculations have, indeed, not been en tirely abandoned, and are not likely to be so long as there is such a thing as philosophy at all. One may instance the speculations of Samuel Alexander about the "emergence" of our world-order out of a more primitive space-time matrix, and the, neutral mon ism of J. Dewey and others. In the main, however, the prevailing tendency in present-day cosmology as a philosophy of Nature is to make explicit and to examine critically all the concepts and assumptions which are employed in the popular and scientific ac counts (whether merely descriptive or explanatory) of the phenomena of Nature, using the term Nature in the restricted sense of the material world (as contrasted with the Spinozistic use of the term for the entire universe, in its spiritual as well as in its material character). A. E. Taylor (Elements of Meta physics, book 3, ch. i.) regards the following as the fundamental problems of cosmology: (I) The real nature of material exist ence, i.e., the ultimate significance of the distinction between physical and mental or spiritual existence, and the possibility of reducing them to one; (2) the justification for the distinction between mechanical and teleological processes, and for the con ception of the physical order as rigidly conforming to uniform law ; (3) the leading difficulties of the conception of space and time, and their bearing on the degree of reality to be ascribed to the physical order; (4) the philosophical implications of the ap plication of the idea of evolution to the events of the physical order ; (5) finally, the problem of the real position of descriptive physical science as a whole. (See COSMOGONY PHILOSOPHY.) BIBLIOGRAPHY.—A. E. Taylor, Elements of Metaphysics Om, etc.) ; Bibliography.—A. E. Taylor, Elements of Metaphysics Om, etc.) ; W. Windelband, Introduction to Philosophy (1923) and History of " Philosophy (1893) ; A. N. Whitehead, Process and Reality, An Essay in Cosmology 0929) ; Hector Macpherson, Modern Cosmologies (193o).
(A. Wo.)