Charles Darwin, after whom social Darwinism is named

Social Darwinism, also known as social Spencerism,[1][2] is a body of pseudoscientific theories and societal practices that claim to apply biological concepts of natural selection and survival of the fittest to sociology, economics, and politics.[3][4] Despite bearing Charles Darwin's name, it is chiefly associated with Herbert Spencer, the main developer and leading exponent of social Darwinist ideas.[1] Social Darwinists believe that the strong should see their wealth and power increase, while the weak should see their wealth and power decrease. Social Darwinist definitions of the strong and the weak vary, and differ on the precise mechanisms that reward strength and punish weakness. Many such views stress competition between individuals in laissez-faire capitalism, while others, emphasizing struggle between national or racial groups, support eugenics, racism, imperialism and/or fascism.[5][6][7] Today, scientists generally consider social Darwinism to be discredited as a theoretical framework, but it persists within popular culture.[8][9]

Although the term is frequently associated with thinkers such as Herbert Spencer or Francis Galton, modern historiographical analysis points out that the epistemological foundations of social Darwinism and early eugenic thought are explicitly present in the writings of Charles Darwin himself.[10][11] In his work The Descent of Man, and Selection in Relation to Sex (1871), Darwin applied his theories on evolution and natural selection to the development of human societies. He argued that competition between different human groups would inevitably lead to the disappearance of certain peoples, describing it as a natural process within the progress of civilization:[12]

Darwin also expressed biological concerns regarding how modern medical advancements and public charity in civilized nations countered the natural process of elimination, allowing individuals with physical or mental disabilities to survive and propagate their kind:[14]

With savages, the weak in body or mind are soon eliminated [...]. We civilised men, on the other hand, do our utmost to check the process of elimination; we build asylums for the imbecile, the maimed, and the sick; we institute poor-laws; and our medical men exert their utmost skill to save the life of every one to the last moment. [...] Thus the weak members of civilised societies propagate their kind. No one who has attended to the breeding of domestic animals will doubt that this must be highly injurious to the race of man.

Charles Darwin, 1871.[15]

Furthermore, he warned about differential fertility rates among socio-economic classes, drawing a direct parallel with the selective pressures used in artificial animal breeding to prevent the degeneration of the population:[16]

The reckless, degraded and often vicious members of society, tend to increase at a quicker rate than the provident and generally virtuous members. [...] Every one who has attended to the breeding of domestic animals will admit that the careful selection of the best individuals is of the highest importance for the welfare of the breed.

Charles Darwin, 1871.[17]

He concluded that the historical and moral advancement of human populations relied heavily on the continuous out-competition and suppression of less capable groups, arguing that social progress was driven by these selective pressures:[18]

The author maintained that this process of replacement was analogous to what is observed in nature when one variety of an animal species displaces another in the same territory.[19] In practice, these assertions provided a theoretical framework to rationalize European colonialism, systemic racism, and, later on, the development of eugenics.[20]

Scholars debate the extent to which the various social Darwinist ideologies reflect Darwin's own views on human social and economic issues. References to social Darwinism since have usually been pejorative.[21][22][23] Some groups, including creationists such as William Jennings Bryan, argued social Darwinism is a logical consequence of Darwinism.[22] Academics such as Steven Pinker have argued this is a fallacy of appeal to nature.[24] While some scholars recognize historical links between the popularisation of Darwin's theory and forms of social Darwinism, they generally maintain that social Darwinism is not a necessary consequence of the principles of biological evolution.[25] Other historians of biology reject the link between Darwinism and social Darwinism on the grounds that Spencer's ideas about evolution deviated from and conflicted with Darwin's.[1]

Social Darwinism declined in popularity following World War I, and its purportedly scientific claims were largely discredited by the end of World War II—partially due to its association with Nazism and due to a growing scientific consensus that eugenics and scientific racism were unfounded.[5][26][21]