In books one and two of Mere Christianity, Lewis’ purpose is to explicate that all human beings have a sense of right and wrong, indicated as the Law of Human Nature, use this Law to support the theory of a God, who gives humans this law and governs them by it, show the difficulty all humans face because they fail to obey this law perfectly, and that Christianity is the only logical answer for this theory to help the modern man into the Christ-life by using analogies, logical deductions, and the Christian dogma. I. Lewis analyses the Law of Human Nature and answers some of his reader’s objections. 3-15) A. When people argue they are appealing to a universal standard of behavior called the Law of Human Nature that they expect everyone else to know and agree upon. (3-7) B. Not all follow this law but they sometimes break it and try to justify their actions by making excuses for what they know they did wrong. (7-8) C. Lewis disproves the idea that the Moral Law is a herd instinct by showing that it is what directs ones instincts by comparing it to a piano which doesn’t have ‘right’ or ‘wrong’ notes, only notes that are right at certain times and wrong at others. (9-12) D.
Lewis disproves the idea that the Moral Law is just a social convention by declaring that one cannot compare another culture’s or era’s moralities as better or worse unless one has a standard morality to compare it to. (12-15) II. Lewis further explains the Law of Human Nature and builds his case for the existence of God. (16-32) A. By comparing it to the Law of Gravitation, Lewis explains that The Law of Human Nature is not a truth about the way things are, but a truth about the way things should be. (16-19) B. The Law of Human Nature is not about what serves one’s own interests or what is helpful to them. 19-20) C. Lewis explains materialism, the belief that the universe has always existed and was not created, and the mathematical values of chance; and spiritualism, that there is a presence behind the universe, a supreme being brought the universe into existence with a clear purpose of creating other beings similar to itself. (21-22) D. Lewis states that science can’t explain the Law of Human Nature because it can’t be seen or otherwise studied. (22-23) E. The Law of Human Nature isn’t a mere fact or a human invention, there must be a God that guides man and makes himself known by the Law of Human Nature. 24-25) F. Lewis declares that humans are in a grim state unless they realize that following the Law is difficult, God is serious about following the Law, and people are fooling themselves if they think there’s an easier way. (25-32) III.
Lewis discusses the inadequacy of the rival concepts of God and the over simplicity of Christianity-and-water. (35-46) A. Lewis discusses the three concepts of God, Pantheism (God is the universe), the Christian idea of God (God made the universe) and Atheism (God does not exist) and concludes that the majority of humans believe in one or more gods. 35) B. Pantheism is discounted by using the analogy that the builder of a house is shown by the existence of the house, but the architect is not a part of the house itself just as God is evidenced in our universe but he is not the universe itself. (36-38) C. Lewis explains that Atheism is too simple of a thought because if the whole universe has no meaning then they should not find out that it has no meaning in the first place. (39) D. Christianity-and-water is can’t be real Christianity because the universe is not simple, so God can’t be simple either. 40-42) E. Lewis shows that Dualism, equality between a Good Power and a Bad Power, can’t be true by arguing that evil is just a perversion of good. (43-45) F. God, though good, created something that turned bad, and there is a dark power in the universe which the New Testament talks about. (45-46) IV. Lewis expounds on the Christian dogma and answers some of man’s questions about God. (47-59) A. God gave us free will because free will is necessary for His creation to love Him in any meaningful way. (47-48) B.
Lewis answers man’s never-ending search for joy apart from God by explaining the first sin-Pride, and how Satan uses it against the human race by putting the idea into their heads that they can be like gods. (49-50) C. Lewis shows that Jesus must either be who he says he is, the Son of God, a madman, or the Devil himself, but He does not leave us the choice of Him being a good moral teacher. (51-52) D. Lewis explains that Jesus Christ is God, the perfect being; who came to earth in order to pay a debt that mankind can’t pay itself. (53-59) V.
Lewis explains and invites the reader to come into the Christ-life. (60-65) A. Lewis specifies how new life is given to Christians through baptism, faith, and Communion, though humans may not understand how. (60-62) B. Christians become a part of the Christ-life and Christ himself but are still imperfect beings that still make human mistakes, but their spirit heals after sinning because of Christ. (62-63) C. The Christ-life is of complete humility and surrender (63-64) D. Lewis concludes by declaring every man will have to choose to accept or reject Jesus Christ (64-65)