The formal systems of logic have ordinarily been regarded as independent of biology, but recent developments in evolutionary theory suggest that biology and logic may be intimately interrelated. In this book, William S. Cooper outlines a theory of rationality in which logical law emerges as an intrinsic aspect of evolutionary biology. He examines the connections between logic and evolutionary biology and illustrates how logical rules are derived directly from evolutionary principles, and therefore, have no independent status of their own. This biological perspective on logic, though at present unorthodox, could change traditional ideas about the reasoning process.