Not to mention the car, central heating, and Google. No mention of the printing press. What outranked the worldchanging device on this list of the "world's best inventions" (or, the opinions of 4,000 Brits as collected by Tesco Mobile)? Penicillin, by a hair. The telephone, the light bulb, and the venerable wheel.

The wonderful, and frustrating, thing about innovation is this: the correlation between what you spend and what you get is often close to zero. If you doubt this, consider two data points. Last year Nokia spent around $7.7 billion on R&D—or 14% of its revenues. Apple, by contrast, spent a comparatively miserly $1.3 billion on R&D--just 3% of its sales. Yet it is Apple, not Nokia, that makes the world’s most desired mobile phones. Want proof?