Not long before he died in 1996, Carl Sagan was interviewed by Charlie Rose and discussed the troubled state of scientific knowledge in America, and how it threatens our democracy. Before Richard Dawkins came along, Sagan was already out there, making the case for scientific thinking, arguing that it let us make progress and keeps our republic vital. (Whether our republic actually remains vital at this point, it's certainly hard to say.) We need more figures like Sagan, and we particularly need the American university system to care more about public engagement -- an area where it depressingly comes up short. But we'll talk more about that at some other point. Part 1 is above. Click for Part 2 and Part 3.