Social degeneration was a widely influential concept at the interface of the social and biological sciences in the 19th century. Degenerationists feared that civilization might be in decline and that the causes of decline lay in biological change. These ideas derived from pre-scientific concepts of heredity with Lamarckian emphasis on biological development through purpose and habit. Degeneration concepts were often associated with authoritarian political attitudes, including militarism and racial science, as well as with fears of national decline. The theory originated in racial concepts of ethnicity, recorded in the writings of such medical scientists as Johann Blumenbach and Robert Knox. From the 1850s, it became influential in psychiatry through the writings of Bénédict Morel, and in criminology with Cesare Lombroso. By the 1890s, in the work of Max Nordau and others, degeneration became a more general concept in social commentary.
The meaning of degeneration was poorly defined, but can be described as an organism's change from a more complex to a simpler, less differentiated form, and in this respect it is associated with 19th century conceptions of biological devolution. Although rejected by Charles Darwin, the theory's application to the social sciences was supported by some evolutionary biologists, most notably Ernst Haeckel and Ray Lankester. As the 19th century wore on, the increasing emphasis on degeneration reflected an anxious pessimism about the of European civilization and its possible decline and collapse.
The concept of degeneration arose during the European enlightenment and the industrial revolution - a period of profound social change and a rapidly shifting sense of personal identity. Several influences were involved.