Mere Christianity | Study Guide

C.S. Lewis

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Mere Christianity | Book 1, Chapter 1 : Right and Wrong as a Clue to the Meaning of the Universe (The Law of Human Nature) | Summary



There is little mention of Christianity in this first book. Instead C.S. Lewis builds the foundation of his apologetic by making a rational argument. Book 1 fulfills the first function of apologia. It uses philosophical methods and historical and scientific evidence to argue for the acceptance of Christian doctrine. Lewis argues two main points: God exists, and humanity is in a dire state due to its constant moral failures. In Books 2, 3, and 4 Lewis will build upon the foundation established in Book 1 with his discussion of Christian doctrine and practice.

"Every one has heard people quarreling," Lewis begins. Humans quarrel by making excuses about why they deviated from some standard of decent behavior that the quarreling parties hold in common. Lewis offers the nature of quarreling as evidence for what he calls the "Law of Human Nature" or the "Moral Law." This Law tells us how to act. We know that we can take right action or wrong action but that we should take right, decent, or fair action.

All people, everywhere, know this same Moral Law without needing to be taught it. Lewis anticipates the obvious criticism that one culture's morality is not at all the same as another's. He does not deny the truth of cultural and historical variation in morality but claims the differences are insignificant. There has never been a morality that does not have at its core the standards that are the Moral Law. No culture has ever valued selfishness, although their standards of selfishness may differ.

Lewis states this universal, inborn Moral Law governs humankind in the same way that laws like gravity govern the material universe. Unlike material laws, however, people can choose whether to obey the Law of Human Nature. In fact breaking the Moral Law is a defining characteristic of humankind. All people do things at times that they know they shouldn't do. Likewise they sometimes fail to do what they know they ought to do. This information—the reality of the Law of Human Nature and our constant failure to keep it—is "the foundation of all clear thinking about ourselves and the universe we live in."


The title for Book 1, "Right and Wrong as a Clue to the Meaning of the Universe," tells the reader that the first five chapters will argue that morality is the key to the existential questions that have preoccupied humanity throughout the ages. The need to understand who we are, where it all came from, and what it all means has driven humankind to some of its greatest achievements in art, philosophy, science, and religion. Humans have approached these foundational questions from all conceivable angles. Some have found answers, while some have found only more questions. At age 30, after living as a staunch atheist, Lewis accepted Christianity as the answer that made sense to him.

But Lewis did not convert as a result of a vision, an event, or any sort of exceptionally vivid experience. His conversion was based on his inability to deny what he considered to be rational arguments for Christianity. Rationality is the tack Lewis takes in Mere Christianity. In Book 1 he works to build the foundations of his apology, or defense, of Christianity as the answer to these profound, universal questions. His tools are reason and logic, not cultural, personal, historical, or emotional claims.

A careful evaluation of his arguments, however, will find that Lewis's premises sometimes rest on weak evidence or on the cursory dismissal of anything that might challenge his assertions. In this chapter he argues for universal moral absolutism. He claims that variations in moral codes can be disregarded without further examination because the similarities outweigh the differences. Lewis's confident absolutism may seem out of touch to present-day readers familiar with postmodern ethics. These specifically deny the existence of an absolute and universal moral standard. Postmodern thought holds that each culture has a unique worldview or version of truth. This worldview corresponds to a set of ethics that arise out of its unique context and experiences. Therefore, comparing one culture's morality to another is like comparing apples and oranges. Since there is no basis for comparison, there is no way to objectively determine what is "right" and what is "wrong." This paradigm is called "cultural moral relativism," and it is worth considering in response to Lewis's claims in this chapter.

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