In the current environment, one is hard pressed to imagine a national broadcast institution like the BBC asking a Christian to explain the intricacies of his faith. Nevertheless, Lewis remains an important figure in the apologetic use of natural law, particularly in the way he demonstrates God as the divine Lawgiver, and couples this with our manifest inability to live up to that law. Such an apologetic is pre-evangelistic in the spirit of the Apostle Paul, who found common ground with the Athenians before he declared the particulars of the unknown God (Acts 17:22-34).

Previously, we examined the way Lewis approaches the law of nature in Mere Christianity. From there, we saw how much of this natural law apologetic resonates with a classical Reformed conception of general revelation and the covenant of works. We now return to Mere Christianity to uncover some important implications for apologetics.

First, one need not take a presuppositional approach to apologetics to prove the existence of God. The Christian apologist finds sufficiency in beginning with human experience and then connecting it to the Christian faith. Even Calvin in his Institutes argues for God’s existence before his formal discussion of Scripture in Book 2.[1] Calvin follows the same approach of Aquinas, who begins with the book of nature.[2] Lewis’ method is akin to the historic catholic tradition whereby the subject is not approached from reasoning seeking faith, but faith seeking reason, modeled after Augustine’s observation:

“For understanding is the reward of faith. Therefore, do not seek to understand in order to believe, but believe that you may understand; since, ‘except you believe, you shall not understand.’”[3]

Augustine’s statement is comparable to Lewis’ own signature declaration of faith: “I believe in Christianity as I believe that the Sun has risen, not only because I see it but because by it I see everything else.”[4]

Second, one need not employ deductive reasoning to prove the existence of God, but he should present a “vision” that appeals to truth, beauty, and goodness. As stated earlier, this approach is inferential, not deductive. Augustine’s prayer, “You have made us for yourself, and our heart is restless until it rests in you,” is entirely consistent with a proper understanding of the residual effects of the Imago Dei from the covenant made with Adam.

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