An Epistemically-Focused Interpretation of C.S. Lewis’s Moral Argument in Mere Christianity and an Assessment of Its Apologetic Force 

Zachary Breitenbach

Lincoln Christian University


C.S. Lewis’s moral argument in Mere Christianity is rightly lauded as an influential contribution to moral apologetics. Yet its structure, which Lewis never formalizes is often misunderstood. I will first defend an interpretation of Lewis’s argument that views it as centering on moral epistemology. Although moral ontology plats a key role in his argument insofar as it affirms the reality of objective morality and a transcendent communicator of the moral law, many wrongly view it as making the further ontological claim that God must ground objective morality. I emphasize how Lewis’s primary aim is to show that a mind-like Guide is needed for humans to know the moral law. My other key objective is to evaluate the apologetic effectiveness of this understanding of the argument. Although I will show how he could have strengthened his argument – and his conclusion, which stops short of arguing for classical theism – in significant ways, I will contend that Lewis does offer a sound argument that carries much apologetic force.