Time travel and the mistake-free life

It's not the kind of question one would expect to hear to conclude a discussion on the physics of time travel, but after watching Princeton astrophysicist Richard Gott (who described "the space colonization imperative" two years ago at the IdeaFestival), and Cal Tech theoretical physicist Sean Carroll (who will speak this year on the many dimensions of time) talk about the intricacies of time travel on the Science Channel show, Through the Wormhole, Morgan Freeman, who hosts, asked the following question. "If we could go back in time to fix our mistakes, would we ever learn anything?"