Environmental determinism and anthropogeography :: ''"Man is the product of the earth's surface."'' Semple was a key figure in the theory of
environmental determinism, along with
Ellsworth Huntington and
Griffith Taylor. Influenced by the works of Charles Darwin and inspired by her mentor Friedrich Ratzel, Semple theorized that human activity was primarily determined by the physical environment. Although environmental determinism is today heavily critiqued and has lost favor in social theory, it was widely accepted in academia in the late 19th-early 20th centuries. Still, Semple's influence can be seen in the works of many modern-day geographers, including
Jared Diamond. In a series of books and papers she communicated certain aspects of the work of German geographer
Friedrich Ratzel to the Anglophone community. Standard disciplinary accounts often attribute to Semple a prevailing interest in
environmental determinism, a theory that the physical environment, rather than social conditions, determines culture; however her later work emphasized environmental influences as opposed to the environment's deterministic effect on culture, reflecting broader academic discontent with environmental determinism after the First World War. In her work ''Influences of Geographic Environment on the Basis of Ratzel's System of Anthropo-Geography'' (1911), she describes people and their associated landscapes, dividing the world into key environmental types. Semple identifies four key ways that the physical environment is affected: 1) direct physical effects (climate, altitude); 2) psychical effects (culture, art, religion); 3) economic and social development (resources and livelihoods); 4) movement of people (natural barriers and routes, such as mountains and rivers). Semple's work also reflects discussions and conflicts within geography and social theory about determinism and race. Indeed, in some works she challenges popular ideas of her time about race determining social and cultural differences, suggesting that environment was a more important factor in cultural development. Semple's theories of environmental determinism have been criticized as overly simplistic and often replicating the same themes of racial determination through "nature". However, Semple's work has more recently been revisited for its early examination of issues which are now central to
political ecology. Semple believed that mankind originated in the tropics but gained full maturity in the temperate regions of the world."where man has remained in the tropics, with few exceptions, he has suffered arrested development. His nursery has kept him a child."
Fieldwork Semple conducted
fieldwork for her research in Kentucky and the Mediterranean, an innovative practice that was uncommon in geography at the time. The main focus of the trip was a three-month visit to Japan, facilitated by her Vassar classmate
Ōyama Sutematsu, which produced unusually positive depictions of Japan during a period of high anti-Japanese sentiment in the United States. During her fieldwork, she took notes on human-environment relations, cultural features of the landscape, and made detailed observations of housing, structures, livelihoods, and daily life. ==Late life==