Book I: Chapter 1 The Law of Human Nature Summary and Analysis

C. S. Lewis lays the philosophical foundation of Book I in the first chapter: there exists a notion of right and wrong that is universal, the Law of Nature. All cultures everywhere agree that this Law of Nature exists, but differ on certain details. One example Lewis uses is marriage. Some cultures allow a single man to marry multiple women, but under the Law of Nature, no one man can have an unlimited number of women whom he desires.

Another argument in favor of the Law of Nature involves how very strange a culture would be if it went against the Law. Lewis suggests that a culture valuing cowardliness over courage would be very strange, as would one overtly rewarding lying and cheating. Lewis brings up our...