The real-world value of knowledge in the mobile-device age. More people know who Khloe Kardashian is than who Rene Descartes was. Most can't find Delaware on a map, correctly spell the word occurrence, or name the largest ocean on the planet. But how important is it to fill our heads with facts? A few keystrokes can summon almost any information in seconds. Why should we bother learning facts at all? Bestselling author William...