Abstract

The main claim here is that Aquinas’s theory of natural law is false because it is incompatible with the occurrence of evolution by variation and natural selection. This contradicts the Thomist opinion that there is no conflict between the two. The conflict is deep and pervasive, involving the core elements of Aquinas’s theory. The problematic elements include: 1) the fundamental precept that good should be done and pursued, and evil avoided; 2) the claim that every organism aims at the good and that it is wrong to frustrate nature; 3) the Aristotelian preconception that everything has a single preeminent end; 4) the putative natural inclinations attributed to human beings; 5) the assumption that species essentialism is true; and 6) the notion that God’s intentions are discernible in the natural world. It is concluded that the problems are so extensive that Aquinas’s theory is beyond rescue.