Social Darwinism and Eugenics of the late nineteenth and early twentieth centuries are often seen as theories based on scientific knowledge. However this is not wholly true. While eugenics was often loosely based on scientific theory, social Darwinism was not at all. One would be hard-pressed to find any science in social Darwinist thought. After reviewing the current literature on social Darwinism it is not clear that there was a cohesive movement of social Darwinism in America at all. When most authors were social theories that most consider to be social Darwinism they did not include the actual term "social Darwinism." Although Eugenics may have been loosely based on scientific theory it in itself was not a scientific theory. Eugenics seems to have been a group of people using at times shaky genetics to spread fear and oppression of the lower classes. Eugenics however did not last in the United States because it left a bad taste in the mouths of scientists when it became known as a science used by the Nazi's. .
In order to discuss Social Darwinism one must first define the term. The problem is that it is a very difficult term to define. Usually when writers in the late nineteenth and early twentieth century wrote on this theory they rarely used the actual term Social Darwinism. Richard Hofstadter presented social Darwinism as a convergence of evolution and social theory. Possibly the only obvious social Darwinist using this definition was Herbert Spencer. It would suit this discussion better to use the Encarta dictionary definition, "a discredited social theory stating that the political and economic advantages in a developed society are derived from the biological advantages of its collective membership." The later definition includes many more social theorists than the previous. I would define social Darwinism as a defunct social theory in which people tried to determine fitness within society using race and class that often was an excuse for acting out on social anxieties of the late nineteenth and early twentieth centuries in industrialized countries.