J. Doyne Farmer
One of the most remarkable things about Ken Arrow was his ability to question his own work. On one hand, he was perhaps the most respected economist of his day. On the other hand, he spent much of the latter part of his career openly admitting that there were serious problems with his work and trying to stimulate others to go beyond it and create something new, even if it was very different from what he did. Such impartial scientific honesty is rare.