Mere Christianity, a seminal work by CS Lewis, has been a cornerstone of Christian apologetics for decades. First presented as a series of radio talks during World War II, this book has been widely acclaimed for its lucid and compelling argument for the Christian faith. Lewis, a renowned scholar and theologian, draws upon his vast knowledge of philosophy, literature, and theology to present a case for Christianity that is both intellectually rigorous and accessible to a broad audience.
The Argument from Morality

Lewis begins by positing that human beings are endowed with a moral sense, which he terms the “Law of Human Nature.” This moral law, he argues, is not simply a product of cultural or societal conditioning, but rather a universal and objective standard that transcends human variation. He contends that this moral law is evidence of a higher power, a divine authority that has imbued human beings with a sense of right and wrong. Through a series of logical and philosophical arguments, Lewis demonstrates that the existence of this moral law is incompatible with a purely naturalistic or atheistic worldview.
The Problem of Evil
One of the most significant challenges to the Christian faith is the problem of evil. If God is all-powerful, all-knowing, and all-good, why does evil exist in the world? Lewis addresses this conundrum by arguing that human freedom is a necessary condition for moral responsibility. He posits that God, in creating human beings with free will, allowed for the possibility of evil, but also provided a means for human beings to overcome evil through redemption. Lewis’s response to the problem of evil is nuanced and multifaceted, taking into account the complexities of human nature and the role of suffering in the human experience.
| Key Concepts | Definitions |
|---|---|
| Moral Law | A universal and objective standard of right and wrong |
| Free Will | The ability of human beings to make choices that are not determined by external factors |
| Redemption | The process of overcoming evil and achieving salvation through faith in God |

Key Points
- The moral law is a universal and objective standard that transcends human variation
- Human freedom is a necessary condition for moral responsibility
- The problem of evil is a complex challenge to the Christian faith, but can be addressed through a nuanced understanding of human nature and the role of suffering
- Redemption is the process of overcoming evil and achieving salvation through faith in God
- Lewis's argument from morality provides a powerful foundation for defending the Christian faith against skeptical critiques
The Trinity and the Incarnation

Lewis devotes significant attention to the doctrine of the Trinity, which he regards as a fundamental aspect of Christian theology. He argues that the Trinity is not a contradictory or absurd concept, but rather a profound and mysterious reality that reveals the nature of God. Lewis also explores the doctrine of the Incarnation, which holds that Jesus Christ is both fully human and fully divine. He contends that this doctrine is not a mere myth or legend, but rather a historical and theological reality that is central to the Christian faith.
The Role of Faith and Reason
Lewis emphasizes the importance of both faith and reason in the Christian life. He argues that faith is not a blind or irrational commitment, but rather a rational and informed decision to trust in God. At the same time, Lewis recognizes that reason has its limits, and that faith must ultimately be grounded in a personal and existential commitment to God. He contends that the Christian faith is not a mere intellectual exercise, but rather a living and dynamic relationship with God that transforms the human heart and mind.
What is the moral law, and how does it relate to the Christian faith?
+The moral law is a universal and objective standard of right and wrong that is rooted in the nature of God. It is a fundamental aspect of the Christian faith, as it provides a basis for understanding the nature of God and the human condition.
How does Lewis address the problem of evil in Mere Christianity?
+Lewis addresses the problem of evil by arguing that human freedom is a necessary condition for moral responsibility. He contends that God, in creating human beings with free will, allowed for the possibility of evil, but also provided a means for human beings to overcome evil through redemption.
What is the significance of the Trinity and the Incarnation in Mere Christianity?
+The Trinity and the Incarnation are central doctrines of the Christian faith that reveal the nature of God and the person of Jesus Christ. Lewis argues that these doctrines are not contradictory or absurd, but rather profound and mysterious realities that are essential to the Christian faith.
As we reflect on the themes and ideas presented in Mere Christianity, we are reminded of the profound impact that this book has had on Christian apologetics and theology. Through his masterful use of logic, philosophy, and literature, Lewis provides a compelling case for the Christian faith that continues to inspire and challenge readers to this day. As we consider the implications of Lewis’s arguments, we are invited to embark on a journey of discovery and exploration, one that leads us deeper into the heart of the Christian faith and the nature of God Himself.