By JIM WATSON / AFP Closing in on his Twitter megadeal, Elon Musk said Thursday his goal is to enable “healthy” debate of ideas and counter the tendency of social media to splinter into partisan “echo chambers.” Closing in on his Twitter megadeal, Elon Musk said Thursday his goal is to enable “healthy” debate of ideas and counter the tendency of social media to splinter into partisan “echo chambers.” The billionaire entrepreneur pursued the deal “because it is important to the future of civilization to have a common digital town square, where a wide range of beliefs can be debated in a healthy…