In this essay, Bradley C.S. Watson gives an introduction to Social Darwinism and its relation to earlier ideas about natural law. The biological theories of Darwin cast into question long-cherished ideas about the human race and led many people to doubt the reliability of traditional arguments about human society. John Dewey and other Social Darwinists attempted to put sociology and politics on a scientific footing by thinking about them in terms of natural selection. Like an organism, they argued, society must grow and develop or die, and just as in Darwin’s Origin of Species, this growth and development could take place only in an environment of adaptation and change. Old philosophical ideas based on putatively permanent and universal truths needed to be discarded in favor of this new philosophy. For the Social Darwinists, traditional thinking about natural law was irrelevant in a scientific age; the purpose of political philosophy would no longer be to discover first principles or ethical rules, but to develop practical solutions to concrete problems. In the source readings associated with this section, you will be able to compare the ideas of the Social Darwinists and consider their implications for society and for morals. As you read, try to determine how these thinkers relate to each other, and how they set up their arguments in opposition to the tradition of natural law thought.