Emergent evolution is the hypothesis that, in the course of evolution, some entirely new properties, such as mind and consciousness, appear at certain critical points, usually because of an unpredictable rearrangement of the already existing entities. The term was originated by the psychologist C. Lloyd Morgan in 1922 in his Gifford Lectures at St. Andrews, which would later be published as the 1923 book Emergent Evolution. The hypothesis has been widely criticized for providing no mechanism to how entirely new properties emerge, and for its historical roots in teleology. Historically, emergent evolution has been described as an alternative to materialism and vitalism. Historical context The term emergent was first used to describe the concept by George Lewes in volume two of his 1875 book Problems of Life and Mind (p. 412). Henri Bergson covered similar themes in his popular 1907 book Creative Evolution on the Élan vital. Emergence was further developed by Samuel Alexander in his Gifford Lectures at Glasgow during 1916–18 and published as Space, Time, and Deity (1920). The related term emergent evolution was coined by C. Lloyd Morgan in his own Gifford lectures of 1921–22 at St. Andrews and published as Emergent Evolution (1923). In an appendix to a lecture in his book, Morgan acknowledged the contributions of Roy Wood Sellars's Evolutionary Naturalism (1922). Origins Response to Darwin's Origin of Species Charles Darwin and Alfred Russel Wallace's presentation of natural selection, coupled to the idea of evolution in Western thought, had gained acceptance due to the wealth of observational data provided and the seeming replacement of divine law with natural law in the affairs of men. However, the mechanism of natural selection described at the time only explained how organisms adapted to variation. The cause of genetic variation was unknown at the time. St. George Jackson Mivart's On the Genesis of Species (1872) and Edward Cope's Origin of the Fittest (1887) raised the need to address the origin of variation between members of a species. William Bateson in 1884 distinguished between the origin of novel variations and the action of natural selection (Materials for the Study of Variation Treated with Especial Regard to Discontinuity in the Origin of Species). Wallace's further thoughts Wallace throughout his life continued to support and extend the scope of Darwin's theory of evolution via the mechanism of natural selection. One of his works, Darwinism, was often cited in support of Darwin's theory.