Herbert Spencer was an English polymath active as a philosopher, psychologist, biologist, sociologist, and anthropologist. Spencer originated the expression "survival of the fittest", which he coined in Principles of Biology (1864) after reading Charles Darwin's 1859 book On the Origin of Species. The term strongly suggests natural selection, yet Spencer saw evolution as extending into realms of sociology and ethics, so he also supported Lamarckism.

Sociology is the scientific and systematic study of human society that focuses on society, human social behavior, patterns of social relationships, social interaction, and aspects of culture associated with everyday life. Regarded as a part of both the social sciences and humanities, sociology uses various methods of empirical investigation and critical analysis to develop a body of knowledge about social order and social change. Sociological subject matter ranges from micro-level analyses of individual interaction and agency to macro-level analyses of social systems and social structure. Applied sociological research may be applied directly to social policy and welfare, whereas theoretical approaches may focus on the understanding of social processes and phenomenological method.