Moral Law as Evidence for God’s Existence

Lewis argues that the universal moral law is evidence of God’s existence. He contends that this moral code, shared across cultures, cannot be explained by human reason or cultural invention. The existence of an objective moral standard suggests a transcendent source, which Lewis identifies as God. This moral law, inherent in human nature, points to a divine legislator, making it a cornerstone of his apologetic for Christianity and the existence of a higher, moral authority.

The Identity of Jesus Christ

C.S. Lewis explores the divine nature of Jesus Christ, arguing that His claims and impact on humanity reveal Him as the Son of God, central to Christianity.

Jesus’ Claim to Divinity

C.S. Lewis emphasizes Jesus’ claim to divinity as a cornerstone of Christianity. Jesus’ statement to forgive sins, a divine prerogative, underscores His assertion of being God. Lewis argues that Jesus’ claims, such as “I and the Father are one,” reveal His divine nature. This claim is central to Christian theology, distinguishing Jesus from a mere moral teacher. Lewis’s Trilemma—Lord, liar, or lunatic—highlights the inevitability of acknowledging Jesus’ divinity, rejecting the possibility of Him being merely human. This claim is foundational to understanding Jesus’ identity and mission.

The Trilemma: Lord, Liar, or Lunatic

C.S. Lewis’s Trilemma challenges skeptics to consider Jesus’ true identity. Given Jesus’ claims to divinity, such as forgiving sins and stating “I and the Father are one,” Lewis argues that Jesus must be either the Lord (God), a liar (deceiving people intentionally), or a lunatic (mentally unstable). This logical framework forces a decision, rejecting the middle ground of viewing Jesus as merely a good moral teacher. The Trilemma underscores the profound implications of Jesus’ claims, compelling believers and skeptics alike to confront His true nature.

The Case for God’s Existence

C.S. Lewis presents a logical argument for God’s existence, rooted in morality and human reason. He posits that the universal sense of right and wrong points to a divine source, arguing that atheism cannot fully explain moral law. By bridging reason and faith, Lewis appeals to skeptics, demonstrating that belief in God is both rational and necessary for understanding humanity’s moral framework and ultimate purpose.

The Argument from Morality

C.S. Lewis argues that morality points to God’s existence, as humans universally recognize a moral law transcending cultural or personal preferences. This moral sense, he contends, cannot be explained by natural causes alone, as it reflects a higher, unchanging standard. Lewis asserts that morality is not merely human invention but a divine imprint on human nature, serving as evidence for a moral Lawgiver. This argument bridges reason and faith, appealing to both believers and skeptics, and is central to his case for God’s existence.

The Role of Reason and Faith

C.S. Lewis emphasizes the interplay between reason and faith, arguing that Christianity is not opposed to rational inquiry. He uses logical arguments, like the moral law, to engage skeptics, showing that faith complements reason rather than contradicting it. Lewis contends that while reason can lead to belief, faith is necessary to fully embrace spiritual truths. This balance between intellect and spirituality makes his apologetics accessible and compelling, demonstrating that Christianity is both rational and transformative.

The Problem of Sin and Redemption

C.S. Lewis explores sin as humanity’s deviation from God’s moral law and presents Christ’s sacrifice as redemption, restoring unity with God and offering eternal life through faith.

Understanding Sin and Its Consequences

C.S. Lewis defines sin as rebellion against God’s moral law, separating humanity from divine intimacy. He emphasizes that sin is not merely wrongful actions but also wrongful attitudes and intentions, reflecting a rejection of God’s authority. Lewis argues that sin leads to moral decay, fostering selfishness and division. This spiritual corruption, if unaddressed, results in eternal separation from God. Lewis underscores that sin is a universal human condition, requiring redemption through Christ’s sacrifice to restore harmony with God and achieve eternal life.

The Sacrifice of Christ and Its Significance

In Mere Christianity, C.S. Lewis presents Christ’s sacrifice as the central act of redemption, satisfying divine justice for humanity’s sin. Lewis argues that Christ’s death was substitutionary, bearing the penalty for human rebellion against God’s moral law. This act demonstrates God’s profound love and mercy, enabling reconciliation between Creator and creation. Through faith in Christ’s sacrifice, individuals are restored to a right relationship with God, overcoming sin’s consequences and securing eternal life. Lewis emphasizes that Christ’s sacrifice is the ultimate expression of God’s grace and humanity’s only path to salvation.

The Doctrine of the Trinity

C.S. Lewis explains the Trinity as God’s three-in-one essence, exploring Father, Son, and Holy Spirit’s unity. This doctrine is central to Christian theology, illustrating divine complexity.

Explaining the Trinity

C.S. Lewis approaches the Trinity as a divine mystery, describing God as three-in-one: Father, Son, and Holy Spirit. He likened it to the sun, its light, and its heat—distinct yet inseparable. Lewis emphasizes that the Trinity is not a contradictory concept but a profound truth reflecting God’s nature. This doctrine, central to Christian theology, underscores the unity and diversity within the Godhead, providing a framework for understanding God’s relational and eternal essence. Lewis’s explanation highlights the Trinity’s significance in Christian belief and worship.

Its Significance in Christian Theology

The Trinity is central to Christian theology, revealing God’s nature as relational and eternal. C.S. Lewis emphasizes that the Trinity reflects divine unity and diversity, illustrating God’s completeness and love. This doctrine underscores the Father’s sovereignty, the Son’s redemptive role, and the Holy Spirit’s transformative power. It unifies Christian beliefs, providing a holistic understanding of God’s character and purpose. The Trinity’s significance lies in its profound implications for worship, fellowship, and the comprehension of God’s eternal, self-giving love, which is at the heart of Christian faith and practice.

The Call to Sacrifice and Discipleship

C.S. Lewis underscores the necessity of surrendering worldly desires and ambitions to follow Christ. True discipleship demands self-denial, yet promises profound spiritual fulfillment and eternal reward.

The Cost of Following Christ

C.S. Lewis emphasizes that following Christ requires radical self-sacrifice and surrender of worldly desires. He argues that true discipleship demands giving up one’s life, ambitions, and comforts to follow God’s will. This call to sacrifice is central to Christian living, as it reflects the profound commitment required to emulate Christ’s life and teachings.

Lewis stresses that this sacrifice is not in vain; it leads to a deeper, more meaningful relationship with God and eternal life. The cost is high, but the reward is immeasurable.

The Reward of Eternal Life

In Mere Christianity, C.S. Lewis presents eternal life as the ultimate reward for following Christ. This divine gift transcends earthly existence, offering a profound union with God. Lewis underscores that eternal life is not merely an endless existence but a vibrant, purposeful relationship with the Creator. It is a reward rooted in sacrifice and faith, promising believers a future filled with joy, peace, and fulfillment beyond human comprehension. This concept is central to Christian theology and a key theme in Lewis’s work.

Criticisms and Counterarguments

Some critics argue that Lewis’s broad approach oversimplifies complex theological issues, while others challenge his moral arguments and the “trilemma” concept. Despite debates, his work remains influential.

Common Criticisms of Lewis’s Arguments

Critics argue that Lewis’s moral argument for God’s existence is insufficient, as moral truths could emerge from natural processes. His “trilemma” is also contested, with some questioning the logic of limiting Jesus to being Lord, liar, or lunatic. Additionally, Lewis’s broad, ecumenical approach is criticized for oversimplifying complex theological issues. Some scholars point out contradictions in his reasoning and argue that his personal beliefs influenced his arguments, undermining their objectivity. Despite these criticisms, his work remains widely respected for its accessibility and philosophical depth.

Responses to Skeptics and Atheists

Lewis addresses skeptics by emphasizing reason and logic, urging them to consider Christianity’s validity. He argues that morality suggests a divine source, countering the notion of purely human ethics. To atheists, Lewis presents Christianity as a rational, cohesive worldview, challenging them to engage with its claims openly. His respectful tone and intellectual honesty make his arguments accessible, encouraging unbelievers to explore faith without dismissing their doubts outright. His approach fosters dialogue, not confrontation.

Mere Christianity remains a powerful exploration of faith, morality, and reason. Lewis’s timeless arguments continue to inspire, offering a clear and compelling case for Christian belief. His work bridges theological divides, emphasizing shared truths that resonate universally. As a foundational text of Christian apologetics, it endures, guiding seekers and strengthening believers in their understanding of God’s love and redemption. Lewis’s legacy in this book is a testament to the transformative power of faith. It is a enduring call to embrace the profound truths of Christianity.

C.S. Lewis’s Mere Christianity explores universal moral law, Jesus’ divinity, and humanity’s need for redemption. Lewis argues that moral law reflects God’s existence, and Jesus’ claims lead to the Trilemma: Lord, liar, or lunatic. He emphasizes sin’s consequences and Christ’s sacrifice as redemption. The book unites Christian denominations by focusing on shared beliefs, offering a logical, compassionate case for faith. Its timeless themes of morality, reason, and grace continue to inspire believers and skeptics alike, solidifying its place as a foundational Christian text.