Monday morning riddle

A father and his son were driving to a ball game when their car stalled on the railroad tracks. In the distance a train whistle blew a warning. Frantically the father tried to start the engine, but in his panic he couldn’t turn the key, and the car was hit by the onrushing train. An ambulance sped to scene and picked them up. On the way to the hospital, the father died. The son was still alive but his condition was very serious, and he needed immediate surgery. The moment they arrived at the hospital he was wheeled into an emergency operation room, and the surgeon came in, expecting a routine case. However, on seeing the boy, the surgeon blanched and muttered, “I can’t operate on this boy – he is my son.”

What do you make of this grim riddle? How could it be? Was the surgeon lying or mistaken? No. Was the surgeon the boy’s true father and the dead man the boy’s adopted father? No. What, then is the explanation?

I first heard this riddle years ago and it really threw me for a loop then. I came across it again in a book called Metamagical themas by Douglas R. Hofstadter. The illustration is the cover of another of his books, The Mind's I: fantasies and reflections on self and soul, co-authored with Daniel C Dennett.