Matthew Arnold contrasted "culture" with anarchy; other Europeans, following philosophers Thomas Hobbes and Jean-Jacques Rousseau, contrasted "culture" with "the state of nature". According to Hobbes and Rousseau, the Native Americans who were being conquered by Europeans from the 16th centuries on were living in a state of nature; this opposition was expressed through the contrast between "civilized" and "uncivilized." According to this way of thinking, one could classify some countries and nations as more civilized than others and some people as more cultured than others. This contrast led to Herbert Spencer's theory of Social Darwinism and Lewis Henry Morgan's theory of cultural evolution. Just as some critics have argued that the distinction between high and low cultures is really an expression of the conflict between European elites and non-elites, some critics have argued that the distinction between civilized and uncivilized people is really an expression of the conflict between European colonial powers and their colonial subjects.