Princeton, N.J. — Edward Witten, who may be the smartest man in the world, seems slightly puzzled by the question put to him: How, his interrogator wants to know, would he describe a typical … ...

The tall, thin, soft-spoken Witten, 52, didn’t even set out to be a scientist. He majored in history at Brandeis and originally planned to be a journalist but ended up getting a Ph.D. in physics ...