But the spread of any new and contagious ideology also has a lot to do with the skillful use of group power. In the late eighteenth and early nineteenth centuries, for example, the Methodist movement became epidemic in England and North America, tipping from 20,000 to 90,000 followers in the U.S. in the space of five or six years in the 1780s. But Methodism’s founder, John Wesley, was by no means the most charismatic preacher of his era. That
