The modern philosophic since the revival of classicism in the Renaissance fall into the same ancient errors. They are either idealistic or naturalistic. If the former, they tend to lose a sense of the finiteness of human nature, conceiving the self as identical with reason. If the latter, modern man seeks to interpret himself wholly with reference to nature. This naturalism has in our times taken concrete expression in Marxism and Fascism.

Over against these anthropologies which fail to do justice to the dimension of human nature, and which, in spite of the inner logic of their assumptions and of the refutations of history, persist in falsifying the human situation by false notions of progress and by false dogmas of human perfectibility, [Reinhold Niebuhr] sets forth the biblical and Christian Anthropology. It takes issue with the utopian optimism of Modernism, but with equal emphasis it repudiates the cynical pessimism that lies at the heart of the age. It views man in terms of both nature and of spirit. He is both in the realm of necessity and in the realm of freedom. At one and the same time man is under the dominion of nature and also transcends nature….

The merit of Niebuhr is that…he sets forth with rigour and consistency in analysis and criticism the fundamental weaknesses and contradictions and the inevitable sterility of the humanistic emphasis. Moreover, I think that Niebuhr’s anthropology is the necessary corrective of a kind of liberalism that too easily capitulated to modern culture. Man who has come so far in wisdom and decency may be expected to go much further as his methods of attaining and applying knowledge are improved. Although such ethical religion is humane and its vision a lofty one, it has obvious shortcomings. This particular sort of optimism has been discredited by the brutal logic of events. Instead of assured progress in wisdom and decency, man faces the ever present possibility of swift relapse not merely to animalism but into such calculated cruelty as no other animal can practice.