Every father knows the disconcerting moment when you see your child as a weird, distorted double of yourself. It is as if for a moment your identities overlap. You see an idea, a conception of your boyish inner self, stand right up in front of you, made real and flesh. He is you and not you, familiar and strange. He is you restarted, rewound; at the same time he is as foreign and unknowable as any other person.