Chapter 23: Watson's Trap — The Unpredictable Variable

He wrote for two hours without stopping, and when he set down the pen his hand ached in the old way it had ached in Afghanistan after long dispatches by firelight, the small muscles protesting a sustained grip. He read back what he had written. Then he crossed out the middle third of it and began again.

The plan that emerged was not elegant. He was aware of this as a fact and refused to treat it as a deficiency.

Holmes had valued elegance — the solution that resolved every variable in a single motion, that clicked shut like a well-made lock. Watson had spent twenty years admiring this quality and another three months, beginning at Reichenbach, understanding that it had a structural weakness: an elegant plan is recognisable as elegant. A man who thinks in formal logical systems can model what an elegant plan looks like from the outside, can predict its probable moves the way a chess player predicts positions, can prepare a response before the opening gambit is even completed.