Lewis was, however, a strong atheist for most of his life. Raised in a religious family, he rejected God and faith at the age of 15. It wasn’t until his adult years that he began to question his resolve, due to a combination of the writings of GK Chesterton and his friendship with JRR Tolkien, a Catholic.
It wasn’t until 1931 that Lewis converted to Christianity. The decision was specifically made while riding in the sidecar of his brother’s motorcycle, on the way to the zoo, before he had published many works.
While none of the philosophies in Lewis’ writing are necessarily new, he popularized several concepts in his fierce attempts to create logical arguments for Christian faith:
Lewis’ Trilemma is the name given to the notion that Jesus cannot simply have been a great human teacher. Due to the claims he made, he must be either a madman, an evil liar, or actually the Son of God.
The concept of a universal morality came up frequently in his writing as well. Both in his fictional stories and non-fiction, he espouses a moral code that everyone knows they should be following. He claimed that there people know what the moral law is and when they break it, as well as the fact that there must be someone or something behind these principles.
Lewis’ view of the afterlife differed from most as well. In works like The Great Divorce he suggests hell to be a place that people can leave at any time – if they are willing to give up the security of isolation and other defenses they have created for themselves.
Since his death, CS Lewis has continued to attract a devoted following, both of his Christian apologetics and fictional stories.