in which the villages, towns, cities, metropolises are formed. As Doxiadis put it, "... This field (ekistics) is a science, even if in our times it is usually considered a technology and an art, without the foundations of ascience - a mistake for which we pay very heavily." Having recorded very successfully the destructions of the ekistic wealth in Greece during WWII, Doxiadis became convinced that human settlements are subjectable to systematic investigation. Doxiadis, being aware of the unifying power of systems thinking and particularly of the biological and evolutionary reference models as used by many famous biologists-philosophers of his generation, especially Sir Julian Huxley (1887–1975), Theodosius Dobzhansky (1900–75), Dennis Gabor (1900–79), René Dubos (1901–82), George G. Simpson (1902–84), and Conrad Waddington (1905–75), used the biological model to describe the "ekistic behavior" of anthropos (the five principles) and the evolutionary model to explain the morphogenesis of human settlements (the eleven forces, the hierarchical structure of human settlements, dynapolis, ecumenopolis). Finally, he formulated a general theory which considers human settlements as living organisms capable of evolution, an evolution that might be guided by Man using "ekistic knowledge". Units Doxiadis believed that the conclusion from biological and social experience was clear: to avoid chaos we must organize our system of life from anthropos (individual) to ecumenopolis (global city) in hierarchical levels, represented by human settlements. So he articulated a general hierarchical scale with fifteen levels of ekistic units: anthropos – 1 room – 2 house – 5 housegroup (hamlet) – 40 small neighborhood (village) – 250 neighborhood – 1,500 small polis (town) – 10,000 polis (city) – 75,000 small metropolis – 500,000 metropolis – 4 million small megalopolis – 25 million megalopolis – 150 million small eperopolis – 750 million eperopolis – 7.5 billion ecumenopolis – 50 billion The population figures above are for Doxiadis' ideal future ekistic units for the year 2100, at which time he estimated (in 1968) that Earth would achieve zero population growth at a population of 50,000,000,000 with human civilization being powered by fusion energy. Publications The Ekistics and the New Habitat, printed from 1957 to 2006 and began calling for new papers to be published online in 2019. Ekistics is a 1968 book by Konstantinos Doxiadis, often titled Introduction to Ekistics. See also Arcology Conurbation Consolidated city-county Global city Human ecosystem Megacity Megalopolis (term) Metropolitan area Permaculture Principles of intelligent urbanism Further reading Doxiadis, Konstantinos Ekistics