"The whole foundation of Christianity is based on the idea that intellectualism is the work of the Devil. " -- Frank Zappa
The whole foundation of Christianity is based on the witness of the apostles to the life, death, burial, and, resurrection of Jesus Christ. They were eye-witnesses of his resurrection. They were also recipients of the outpouring of the Holy Spirit which he had promised and which they passed on to his followers and which is available to believers today. The Christian faith is historical as well as existential. It is propositional as well as experiential. It encompasses the mind, the will, and the emotions of the Christian. It affects the body, the soul (mind, will, emotions) and the spirit (inner immaterial being) of man.
Faith in the heart and mind of the believer can range from the simple Forrest Gump variety to sophisticated Augustine. God accepts both. Children can possess and enjoy what the cleverest atheist can only press his nose against the glass and vacuously ponder.