Presupposing that all knowledge is the study of a unitary order of nature, the author maintains that the study of literature should be included within the larger field of evolutionary theory. He outlines four elementary concepts in evolutionary theory, and he argues that these concepts should regulate our understanding of literature. On the basis of these concepts, he repudiates the antirealist and irrationalist views that, under the aegis of "poststructuralism," have dominated academic literary studies for the past two decades. He examines the linkage between poststructuralism and standard social science, and he speculates about the ideological and disciplinary motives that have hitherto impeded evolutionary study in both the social sciences and the humanities. Finally, he distinguishes literature from science and argues that literary criticism integrates elements of both.