It may be a common religion, common studies, a common profession, even a common recreation. All who share it will be our companions; but one or two or three who share something more will be our Friends. In this kind of love, as Emerson said, Do you love me? means Do you see the same truth? — Or at least, “Do you care about the same truth?” The man who agrees with us that some question, little regarded by others, is of great importance can be our Friend. He need not agree with us about the answer.
— C.S. Lewis, The Four Loves