Answers to Misgivings

Big idea

Summary

Lewis uses this chapter to address misgivings raised by the previous two chapters. One worry is that his argument, if valid, would undermine trust in all reasoning whatsoever, including science — surely too high a price. Lewis's response is to distinguish sharply between reasoning that is caused by, and answerable to, real logical grounds (the kind every scientist actually relies on when following an argument to its true conclusion) and reasoning that is caused only by non-rational physical or chemical events with no reference to logical validity at all. His argument targets only the second picture — Naturalism's picture — not reasoning as such.

A second misgiving is that Lewis's argument looks suspiciously like a rhetorical trick, a way of arguing anyone into supernaturalism regardless of the actual merits of the case. Lewis answers that he is not claiming every act of thinking proves Supernaturalism directly; he is claiming that the very possibility of valid reasoning — reasoning that reliably tracks truth rather than merely following the drift of prior causes — requires that reason not be wholly a product of a self-contained natural system with no reference beyond itself.

He closes by acknowledging that this leaves plenty for a Naturalist to still say in reply, and that the argument does not, by itself, prove Christianity, or even full-blown theism; it only shows that Nature cannot be the whole of reality, since something about the reliability of reason (and, as the previous chapter showed, of morality) has to come from beyond her. That is exactly the modest, but real, opening the rest of the book will build on.

Key points

• Lewis distinguishes reasoning that tracks real logical grounds from reasoning that is merely caused by non-rational events; his critique targets Naturalism's picture, not reasoning as such.
• He denies that his argument is a rhetorical trick: the claim is only that valid reasoning requires something beyond a self-contained, non-rational natural system.
• The argument does not, on its own, prove Christianity or even full theism; it only shows Nature cannot be the whole of reality.
• This modest but real conclusion — that something exists beyond Nature — is the foundation the rest of the book builds on.

For reflection and discussion

1. Lewis is careful to say his argument proves less than readers might expect — not Christianity, only that Nature isn't the whole of reality. Why might it matter to argue this cautiously rather than overclaiming?