From a historical point of view, what is Social Darwinism?
Social Darwinism was a social philosophy that emerged in Europe and America of the late 19th Century and early 20th Century. The basic premise of Social Darwinism resided in taking the Darwinian "survival of the fittest" and applying it to modern life. The historical roots of the movement consisted of essentially vulgarizing Darwin's intricacy and making it into a pretext for subjugation, free market economic domination, and for eugenics. Throughout the historical growth of the late 19th and early 20th Centuries, Social Darwinism was used to justify exploits of power by those in high status, mostly at the cost of those beneath them. Social Darwinism became an "anything goes" philosophy that sought to advance the claims of power.
The historical use of Social Darwinism denies the complexity of the evolutionary theory. Those that used Social Darwinism and advanced it never quite "got" that Darwin's evolutionary theory took millions of years and that within this framework and context, no one organism could claim dominion over all others. At the same time, those who were advocating Social Darwinism failed to understand that Darwin's theory of evolution essentially embraced a homeostatic condition of nature in which all organisms understood the need to adapt to circumstances around them. This adaptability is applicable to all creatures, not to "the powerful" ones. From a historical point of view, evolutionary theory was discarded by those who used Social Darwinism as a means to advocate a new social and political order of power consolidation.