“There is a sense in which Arthur and Barfield are the types of every man's First Friend and Second Friend. The First is the alter ego, the man who first reveals to you that you are not alone in the world by turning out (beyond hope) to share all your most secret delights. There is nothing to be overcome in making him your friend; he and you join like rain-drops on a window. But the Second Friend is the man who disagrees with you about everything. He is not so much the alter ego as the anti-self. Of course he shares your interests; otherwise he would not become your friend at all. But he has approached them all at a different angle.”