Social-Darwinism is a socio-economic and political philosophy based on the notion of "survival of the fittest". It emerged in the late 19th century and has been used to justify unequal distribution of resources in society. Other terms that have been used as synonyms for social-Darwinism include social evolutionism, darwinian economic theory, and biological determinism. These terms all refer to the idea that individuals and societies evolve and progress based on their inherent biological characteristics, and that only the fittest members of society should survive and flourish. While these terms have been used interchangeably, their usage and specific meanings may vary depending on context and historical period.