When Alfred Nobel wrote a will leaving his fortune to underwrite annual prizes for intellectual achievement, he specified that one be given "to the person who shall have made the most important discovery or invention within the field of physics."

To the credit of the judges, they didn't take his instructions too literally. Nobel accolades are best heaped upon fundamental insights. Practical inventions get other rewards.

Usually the theoretical does win out. This year's physics winner was an exception—blue LEDs, or light-emitting diodes, hailed in a news release from the Nobel Foundation as "a new energy-efficient and environment-friendly light source."

Perhaps they were making up for awarding last year's prize to the Higgs boson. That discovery will never illuminate most people's lives,