Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Emergent evolution is the hypothesis that, in the course of evolution, some entirely new properties, such as life and consciousness, appear at certain critical points, usually because of an unpredictable rearrangement of the already existing entities. The concept has influenced the development of systems theory and complexity theory. The word 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 the popular book Creative Evolution in 1907. It was further developed by Samuel Alexander in his Gifford Lectures at Glasgow during 1916-18 and published as Space, Time, and Deity (1920). The 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 one lecture in his book, Morgan acknowledged the contributions of Roy Wood Sellars' Evolutionary Naturalism (1922).