Development

Development is a term used in several special or technical senses. In mathematics it means the process by which any mathematical term is changed into another of equivalent value or meaning; in geometry specifically the unrolling of a cylindrical or conical surface, the unbending of any curved surface into a plane, is called development. The word is sometimes used of the whole field of Embryology (q.v.) and of Evolution (q.v.), but is specially applied rather to the theories of Lamarck (q.v.) than to the Darwinian Theory (q.v.); see also the articles BIOLOGY, HEREDITY, MAN, VARIATION, WEISMANN. The history of every science, art, or invention is a history of progress and development. (See ANTHROPOLOGY, ART, and the relevant sections of the articles on sciences, &c., throughout the work.) The word has its own meaning in Photography (q.v.); in music the development of a musical phrase or subject is the unfolding of its capacities by modification of melody, harmony, tonality, rhythm, &c. (see SONATA); and development of doctrine is dealt with in the articles DOGMA (q.v.), CHRISTIANITY, NEWMAN, and ROMAN CATHOLIC CHURCH.