I. The Issue of Presuppositions
A. In this book Lewis comes closest to what might be called a presuppositional apologetic. When unbelievers behave themselves, he is evidentialist. When they do not, he becomes a radical presuppositionalist.
B. He understands the power of paradigms. “What we learn from experience depends on the kind of philosophy we bring to experience” (p. 7).
II. The Naturalist Self-Contradiction
A. “All possible knowledge, then, depends on the validity of reasoning” (p. 19).
B. “It follows that no account of the universe can be true unless that account leaves it possible for our thinking to be a real insight” (p. 20).
C. “We may in fact state it as rule that no thought is valid if it can be fully explained as the result of irrational causes” (pp. 20-21).
D. “The finest piece of scientific reasoning is caused in just the same irrational way as the thoughts a man has because a bit of bone is pressing on his brain” (p. 22).
E. But they manage to get along anyhow. “The claim is surrendered only when the question discussed in this chapter is pressed; and when the crisis is over the claim is tacitly resumed” (p. 24).
III. The Ethical Impasse
A. “But if Naturalism is true, ‘I ought’ is the same sort of statement as ‘I itch’ or ‘I’m going to be sick’ (p. 36).
B. “A moment after they have admitted that good and evil are illusions, you will find them exhorting us to work for posterity, to education, revolutionise, liquidate, live and die for the good of the human race” (p. 37).
C. “Do they remember while they are writing thus that when they tell us we ‘ought to make a better world’ the words ‘ought’ and ‘better’ must, on their own showing, refer to an irrationally conditioned impulse which cannot be true or false any more than a vomit or a yawn?” (p. 37).
D. “The Naturalists must not destroy all my reverence for conscience on Monday and expect to find me still venerating it on Tuesday” (p. 38).
IV. Getting Clear on Christianity
A. “But you cannot do that [dispense with the miraculous] with Christianity. It is precisely the story of a great Miracle. A naturalistic Christianity leaves out all that is specifically Christian” (p. 69).
A. Lewis has shown that any Naturalist objection to the reality of miracles cannot be sustained for the simple reason that Naturalism itself cannot be sustained. And this brings us to the existence of God.
B. “That is the bargain. Theology says to you in effect, ‘Admit God and with Him the risk of a few miracles, and I in return will ratify your faith in uniformity as regards the overwhelming majority of events’” (p. 109).
C. “The process grows narrower and narrower, sharpens at last into one small bright point like the head of spear. It is a Jewish girl at her prayers” (p. 121).