[ Sat. Jan. 20. 2007 ]

'What are you optimistic about?" editor John Brockman asked some of the world's leading scientists on his Web site, www.edge.org.

As I've yet to complete my unified theory of the universe, he did not include me in his survey. If he had, I'd have answered: Just about everything.

As I reported in last week's column, Brockman's respondents were forward-looking, describing cutting-edge research that will help combat global warming and other looming problems. My optimism is anchored in the past.

By almost any measure -- greater wealth, better health, diminishing levels of violence -- the world is good and getting better. My only regret is that I am alive today because tomorrow will be even brighter.

Where to start with the good news? How about with the Big Kahuna: During the 20th century, life spans for the average American rose from 44 years to 77 as we tamed age-old scourges such as smallpox, malaria, polio and plague.