Franklin was exasperated when the convention declined to hire a chaplain to lead the prayers. But perhaps the speech still had a unifying effect, as Franklin later helped to craft the “Great Compromise” over representation in the House and Senate, arguably the critical agreement of the whole convention.In pioneering this doctrineless, moralized Christianity, Franklin was helping to develop one of the most common forms of spirituality in modern America. Adherence to specific beliefs and congregations is slipping in many sectors of America today, but Americans remain an overwhelmingly theistic people. Self-help celebrities and writers from Oprah Winfrey to Steven Covey reach audiences in the hundreds of millions with their quasi-religious messages about living a life of maximal goodness and significance. Even popular preachers like Houston megachurch pastor Joel Osteen downplay doctrine in favor of practical sermons and books on living “your best life now.”Franklin’s Christian friends and relatives were always worried that the great printer, scientist and diplomat might be gaining the world but losing his soul. Traditional Christians today would likewise argue that authentic faith is based upon true beliefs about God, Jesus and the Bible. But the “deist” Franklin was convinced that in crafting a doctrineless, moralized Christianity, he was redeeming the best of traditional religion by channeling it toward the ideals of love and charity.

Thomas S. Kidd is the author of “Benjamin Franklin: The Religious Life of a Founding Father” (Yale University Press, 2017).