Would time travel be a good thing for the world? Or would it wipe out our universe, creating a new timeline in which you and I might not even have been born? And as a result, should the government be supporting or hindering time travel research? That's the dilemma that econo-blogger Tyler Cowen struggles with, over at Marginal Revolution. He adds: "Alternatively, imagine yourself as a benevolent philanthropist: should you support this area of research if you can do so as a free lunch? Or should you try to hinder it?"
The comment thread is also worth reading, for people's differing theories about the "rules" of time travel, whether you can change the past, and what sort of investment opportunities we could offer to time travelers as a bonus incentive. [Marginal Revolution]