John Horgan examines how Americans seem to have a completely different attitude toward war than we did thirty years ago. He takes us on a stroll through Hoboken, asking strangers one of the great unanswerable questions: "Will humans ever stop fighting wars?" Strangely, everyone seems to know the answer. Robert Sapolsky brings us farther afield - to eastern Africa, where a population of baboons defies his expectations of violent behavior. Robert is surprised to feel hopeful for a gentler future, but then primatologist Richard Wrangham asserts that their aggressive nature is innate, unchanging, and hanging over them like a guillotine.