Mere Christianity: A Brief Summary

    C.S. Lewis summarized Christianity on BBC Radio during WWII. His segments were the most listened to in the UK, second only to Sir Winston Churchill. These segments were split into parts, and then published in parts. Lewis later compiled these talks into one book with four parts, Mere Christianity. In this essay, I will summarize the three most important aspects of Christianity articulated by C.S. Lewis in Mere Christianity: Belief, Behaviour, and Transformation.

The Law of Human Nature

    C.S. Lewis goes through these three aspects in a way that assumes the occurrences of belief, behaviour and transformation typically happen in this order. Before reaching the point of Christian belief in Book II, he first expounds, in Book I, on the belief in a universal God. The main point in his argument for believing in God is the existence of the ‘Law of Human Nature’, or the ‘Rule of Right and Wrong’. The understanding of the Law of Human Nature is essential to all three aspects of Christianity; that is Belief, Behaviour, and Transformation (31). Therefore, before moving onto these aspects, I will first summarize Lewis’ points on his idea of universal morality.

    Lewis has two points to make in regard to Human Nature: “First, that these human beings, all over the earth, have this curious idea that they ought to behave in a certain way, and cannot really get rid of it. Secondly, that they do not in fact behave that way,” (18). The first point that the human race, across cultures and generations, shares this common moral ground is not, and cannot be, confused with, what Lewis calls, the ‘Rule of Decent Behaviour’: behaviour which is taught, such as manners. By comparing all cultures, he finds a striking and inexplicable pattern of morality which is rooted in the virtue of selflessness. He says, “Think of a country where people are admired for running away in a battle, or where man felt proud for double crossing all the people who had been kindest to him,” (6). 

    Lewis then argues against the idea that this innate sense of morality shared throughout mankind is caused by evolutionary instinct, for “it usually seems to be telling us to side with the weaker” of our conflicting impulses: the selfless impulse (10). This Law isn’t one of our instincts, but is the power which helps us choose between two or more instincts. He shows that one instinct isn’t always right in every situation and is opposed by an instinct which isn’t always wrong. Mother-love can become obsessive and possessive. Aggression can be good when defending an innocent person from being attacked. “Strictly speaking, there are no such things as good and bad impulses… The Moral Law… is something which makes a kind of tune by directing the instincts,” (11). As opposed to many modern Christian beliefs today, morality is not simple and basic human actions are not inherently evil. He concludes that this discerning power must be outside the universe, for it does not show itself as a part of the universe, but as that which influences all the parts of the universe (24). And this is what we call God.

Belief

    I will now move on to Book II of Mere Christianity, which centres on Christian belief. First, there is the Gospel. C.S. Lewis states, “the central Christian belief is that Christ’s death has somehow put us right with God and given us a fresh start,” (54). There are theories as to how this logically worked, but that is not central to this essay (nor, I believe, fully in our power to understand). The doctrine that Jesus Christ was God incarnated is also central to the gospel. Lewis uses the three-fold argument which claims Jesus was either a liar, a lunatic, or the true Son of God. By disproving the first two possibilities and using the process of elimination, he concludes that it is only logical to assume Jesus was telling the truth (52).

    The last point of Christian belief is salvation. Lewis doesn’t limit this mysterious reconciliation with God to a physical prayer or action, but he parallels it to a broader experience. He says, “This willing submission to… a kind of death is not something God demands of you before He will take you back… it is simply a description of what going back to him is like,” (57). Salvation is letting God make you good out of the Love that he shares (63).

Behaviour

    This leads to the second most important aspect of Christianity, the transformation of behaviour; or what Christians call sanctification. Traditionally, this is necessary evidence of the saving work of Christ. However, Lewis may go so far as to say sanctification and salvation are one of the same. But how exactly do we see this? Lewis sums it up in three parts; “fair play and harmony between individuals… harmonizing the things inside each individual… and the general purpose of human life as a whole,” (72). 

    Lewis spends a lot of time in the book outlining the specifics of these three ways which we must be put right in. There’s the Cardinal Virtues (76), the Virtue of “Loving thy Neighbour” (82), Sexual Morality (94), and Christian Marriage (104). These all correspond to our correction in how we should treat others. Then he touches on Pride (121), Forgiveness (115), and the Theological Virtues of Charity (129), Hope (134), and Faith (138, 144), which correspond with correcting that which is inside our souls. And of course, all of the above helps us in fulfilling our unified role in the universe; “Not hoping to get Heaven as a reward for your actions, but inevitably wanting to act in a certain way because a first gleam of heaven is already inside you,” (148). Thy Kingdom come, Thy will be done, on Earth as it is in Heaven, through our active and continually transforming lives.

Transformation

    The third aspect of Christianity is actually a reflection on what we have discussed. Through the very experience of being transformed in mind, body, and spirit, we are enabled to believe and understand the loving nature of God, the power of the cross, and the renewal of who we are in light of these things. We are to be transformed into “little Christs,” (199). By giving oneself up to “His Personality [we] first begin to have a real [individual] personality of [our] own,” (226). Jesus promises to make us perfect throughout eternity, even if he has to open the gates of heaven to death and suffering and evil, he will make us perfect so that we may know the full joy and fullness of life, and he will do nothing less (paraphrased, 202). 

    Lewis ends the book by closing the circle: “The very first step is to try to forget about the self altogether,” (226). Selflessness: That which unites mankind is the gateway and foundation for finding God and our true purpose in him: to be consummated into that which is greater, more beautiful, and more life-giving then anything we can imagine. 

    Whoever loses their life will find it.