The philosopher Jon Barwise died at the age of 57. Here is all you want to know, and more!
Biography - A Short Wiki
American philosopher and mathematician best remembered for his revisions on the theory of logic.
His family was residing in Independence, Missouri, when he was born.
Jon Barwise, a logician renowned for his research in mathematical logic, his ingenuity in applying mathematical techniques to outstanding problems in other disciplines, and his pioneering efforts in logic pedagogy, died of cancer March 4, 2000, in Bloomington, Ind.