Clive Staples Lewis emerged as one of the 20th century’s most influential Christian writers despite coming to faith relatively late in life, after years of atheism. Born in Belfast in 1898, Lewis served in World War I before pursuing an academic career at both Oxford and Cambridge, becoming a renowned scholar of medieval and Renaissance literature. His conversion to Christianity produced a remarkable output of apologetic, theological, and imaginative works that made Christian orthodoxy more accessible to modern audiences. His approach combined intellectual argument with imagination, as demonstrated in works ranging from The Chronicles of Narnia to Mere Christianity, making him one of the most widely read Christian authors of his era.

Lewis’s apologetic method was characterized by his ability to articulate what he regarded as the underlying assumptions and desires that shape human behavior, particularly in relation to pride, pleasure, and the search for meaning. His Mere Christianity, which originated as a series of radio talks during World War II, presents Christian core beliefs shared across many Christian traditions. The work’s chapter on pride, which Keller draws upon extensively, presents pride as fundamentally competitive rather than merely excessive.

In The Freedom of Self-Forgetfulness, Keller employs Lewis to elaborate his diagnosis of the ego’s pathology. The extended quotation from Mere Christianity about pride’s competitive nature complements Keller’s argument that the human ego is perpetually busy comparing itself to others and boasting. Additionally, Keller references Lewis’s observation about truly humble people: That one would never leave their presence thinking about their humility, because genuinely humble people are characterized not by constantly disclaiming their worth but by simply not thinking about themselves. This description illuminates Keller’s paradoxical claim that gospel-humility means not thinking less of oneself but thinking of oneself less, with Lewis’s psychological argument aligning with Keller’s interpretation of Paul’s biblical teaching.

Søren Kierkegaard stands as one of the 19th century’s most famous philosophers, often regarded as the father of existentialism despite his passionate commitment to Christian faith. Born in Copenhagen in 1813, Kierkegaard developed a philosophical and theological approach that emphasized individual existence and the anxiety inherent in human freedom. 

His work arose partly in reaction to the dominant Hegelian philosophy of his time, which he saw as reducing Christianity to an abstract system of ideas, and partly in response to what he perceived as the complacent, culturally accommodated Christianity of the Danish state church. Through a series of pseudonymous works as well as explicitly Christian writings, Kierkegaard explored the psychological and spiritual dynamics of human existence, focusing particularly on concepts like despair, anxiety, faith, and the difficulties of authentic Christian discipleship. His most influential books include such works as Fear and Trembling and The Concept of Anxiety.

Kierkegaard’s Sickness Unto Death, published in 1849, analyzes despair as the defining characteristic of human existence apart from proper relation to God. In this work, Kierkegaard argues that the self is fundamentally relational—it is established by God and finds its true identity only in relation to God. The various forms of despair that Kierkegaard catalogs all stem from the attempt to ground the self in something other than God, whether in worldly achievement, in one’s own powers, or in defining oneself against God. He insists that human beings cannot create their own meaning or establish their own identity successfully—the self is designed to find its center in God alone.



Keller draws upon Kierkegaard when claiming that identity must be grounded in God rather than in human achievement. Keller cites Sickness Unto Death to support his diagnosis of the ego’s emptiness. Kierkegaard’s insight undergirds Keller’s claim that the overinflated ego is actually empty at its center. By invoking Kierkegaard, Keller once again aligns himself with previous Christian thinkers, presenting his work as a continuation of an important theological discussion.