I READ a short story once in which an old master a Rembrandt was discove red in an attic and a huge argument ensued among experts about whether such a treasure could possibly have lain undiscovered for centuries and actually be genuine. Then, six months later, a second and identical painting turned up. Clearly they could not both be genuine, but the debate then turned on which was the fake. That was the twist in the story. In fact, both were fakes but people did not think of that possibility. In the excitement, faced with a difficult choice, they assumed one must be genuine and mobilised all...
