He begins chapter one of Book Two by pointing out an important difference between the Christian worldview and the Atheist/Materialist worldview. Christians are not required to believe that all other religions are completely invalid and wrong with absolutely no truth in them, but "if you are an atheist, you do have to believe that the main point in all the religions of the whole world is simply one huge mistake," which would mean that most of the human race have always been wrong about the question of our existence and the purpose for it. Even when Christianity claims to be the exclusively right answer, it can still acknowledge and find shreds of truth in even the strangest religions, but the Atheist who is consistent within his worldview must view them all (and view those who believe in them) as wrong, mistaken, and wholly false.
Lewis goes on to explain two main divisions that people generally fall under:
After describing some of the different perspectives of pantheism (many gods) and monotheism (one God), Lewis then goes on to give a basic summary of the Christian worldview of God:
but many of those things have gone wrong,
and God wants them to be made right again.
Whatever your worldview is, can you really defend and explain why you believe it?
Do you think it's important to be able to do so?