The Intertwining of Natural Law and the Laws of Nature in Thomas Aquinas

Abstract

The essay seeks to understand better the relationship between the laws of nature and the natural law. It considers, first, Thomas Aquinas's position on killing another in self-defense. For Thomas, the morality of killing in self-defense depends on laws issued by humans. This brings the morality of killing in self-defense, although not unconnected with the laws of nature, into the realm of natural law. The essay moves on then to what Aristotle says about murder, theft, adultery. It argues that, of these three, adultery, although dependent upon with human laws, is closely tied up with the laws of nature. The essay also argues that the prohibition against adultery is, in turn, tied up with prohibition against lying. Finally, making special use of Thomas's centrally important article on the natural law (ST 1-2.94.2), where he also invokes the principle of non-contradiction, the essay argues that the morality of self-defense and sexual morality are not as disparate as they may seem.