Why do some of us believe, and some of us don't? And can doubt bring our beliefs into sharper focus? In this hour, TED speakers, from ardent aetheists to the devout, explore all ends of the spectrum. In a brand new interview, minister Greg Tonkinson describes how he had to reckon with doubt when his faith was shaken to its core. Other guests from the original 2013 episode include actor Julia Sweeney, and writers Lesley Hazelton, Alain de Botton, and Devdutt Pattanaik.