Social Darwinism was a prominent ideology in the late-nineteenth and early-twentieth centuries that emerged when biologists and social thinkers tried to apply the biological theories of Charles Darwin (1809–1882) to human society. Social Darwinists believed that humans were subject to scientific laws, including Darwinian natural selection and the struggle for existence. They viewed human competition as a beneficent force bringing progress. However serious differences emerged among those who tried to formulate social theories based on Darwinism. One of the most controversial disputes among social Darwinists was whether humans should model their societies on nature or use scientific knowledge to vanquish nature. Specifically the question was whether humans should sharpen or soften the struggle for existence. Though most social Darwinists never admitted it, this fundamental question was not tractable scientifically, but depended on one's ethical perspective, because Darwinian processes could not predict future outcomes nor provide moral guidance...