Christian apologetics
Lewis the Christian
Before writing his Christian fiction books, C.S. Lewis was known as an apologist: a writer who defended his faith using logic.
Lewis saw his books as a layman's view. He tentatively advanced many unorthodox ideas, showing imagination and new approaches. His most famous apologetic works are The Problem of Pain, Miracles and Mere Christianity.
A student called Elizabeth Anscombe criticised Miracles in February 1948 at a meeting of the Oxford Socratic Club. Anscombe, a Roman Catholic, was not trying to disprove Christianity or attack Lewis's faith, but she did find errors in his logic.
Lewis's friends later described this debate as deeply humiliating for him and said it stopped him writing more books on theology. Anscombe does not remember the debate that way: quoted in George Sayer's biography of Lewis, she said it was a "sober discussion" and that Lewis accepted her criticisms. He rewrote a chapter of his book following Anscombe's criticisms.
Whatever the effect on Lewis, it is true that he was chastened. He was concerned that the public might confuse the disproof of a logical argument for God with a disproof of God himself. He realised that trying to prove God's existence through reason had been a mistake, and from then on his Christian writings were more concerned with intuitive faith and feeling.
It was not long after this time that Lewis wrote his series of classic children's books, beginning in 1948 with The Lion, the Witch and the Wardrobe.
I do not think there is a demonstrative proof ... of Christianity, nor of the existence of matter, nor of the good will and honesty of my best and oldest friends. I think all three (except perhaps the second) far more probable than the alternatives.C.S. Lewis, from a letter of 23 December 1950
Atheism and pessimism
All these were rosy visions of the night,
The loveliness and wisdom feigned of old.
But now we wake. The East is pale and cold,
No hope is in the dawn, and no delight. C.S. Lewis, Spirits in Bondage I,VII
Lewis described himself as a pessimist in his early years. His experiences as a child, whether his physical clumsiness or the death of his mother, taught him to expect things to go wrong. Some years before converting to Christianity, the young Lewis wrote a series of poems published as Spirits in Bondage. Although at this time he was calling himself an atheist, the poems show that he was greatly concerned with the idea of God's cruelty or indifference. "The sky above is sickening, the clouds of God's hate cover it" he wrote. (Spirits in Bondage I,VIII)
He later wrote in Surprised by Joy that he "was living in a whirl of contradictions. I maintained that God did not exist. I was also very angry with God for not existing. I was equally angry with Him for creating a world."
After becoming a Christian, Lewis's outlook seems to have been transformed and he became more positive, even extroverted. "I had been, as they say, 'taken out of myself.'"