ABSTRACT
A Darwinian view of human nature can support the natural law reasoning of Thomas Aquinas. The biological character of the natural moral law is suggested by a famous statement by Ulpian, an ancient Roman jurist: "Natural right is that which nature has taught all animals." This chapter develops the common ground that exists between Aquinas, Adam Smith, Charles Darwin, Edward Westermarck, and Edward O. Wilson. It indicates how biological reasoning about human nature can strengthen the case for natural law by giving it the support of Darwinian science. The chapter uses sexual mating, parental care, and familial bonding as examples of the biological basis of natural law. It argues that Darwinian biology supports the natural law understanding of ethics by showing how such inborn desires and cognitive capacities arise as products of human biological nature. The chapter also argues that Aquinas's view of natural law and Wilson's view of human biology belong to the same intellectual tradition of ethical naturalism.
