In 1973, he wrote the memo that invented Ethernet. Three years later, he, with David Boggs, had the system up and running. Yet, his practical application of the theoretical system he dreamed up in 1973 actually provoked not applause among his engineering colleagues but vexed controversy. Their response to the functioning Ethernet was that it was impossible. Their reason? It was impossible "in theory." As Ethernet's use spread, there remained engineers who scoffed at it as a theoretical impossibility. That reminds me of the old joke Ronald Reagan used to make at the expense of economists. "Yes," they might say. A certain policy, say tax cuts, works in practice. "But does it work in theory ?"
Tax cuts, incidentally, and the efficiency of American markets explain the long period of vigorous economic growth that the country has enjoyed since the early 1980s. Yet there is another element, one mentioned by Fed Chairman Alan Greenspan frequently. That is the growth in productivity stemming from the surge in scientific and technological innovation that was celebrated this week with the National Science and Technology Medals. The event brought together stars far more worthy of our awe than any stars the world of entertainment might summon to dinner. I actually got to meet Vint Cerf and Bob Kahn, the men who took Metcalfe's Ethernet and made it the Internet. I suspect the economic impact of these three men has amounted to hundreds of billions of dollars. What is more, there is no sign the innovations are ending.