'I am afraid that when we describe a man as "a member of the Church" we usually mean nothing Pauline: we mean only that he is a unit - that he is one more specimen of some kind of things as X and Y and Z. How true membership in a body differs from inclusion in a collective may be seen in the structure of a family. The grandfather, the parents, the grown-up son, the child, the dog, and the cat are true members (in the organic sense) precisely because they are not members or units of a homogeneous class. They are not interchangeable. Each person is almost a species in himself. The mother is not simply a different person from the daughter, she is a different kind of person. The grown-up brother is not simply one unit in the class children, he is a seperate estate of the realm. The father and the grandfather are almost as different as the cat and the dog. If you subtract any one member you have not simply reduced the family in number, you have inflicted an injury on its structure. Its unity is a unity of unlikes, almost of incommensurables.'
CS Lewis, 'Membership' in The CS Lewis Essay Collection: Faith, Christianity and the Church, p.335.
