Typically, critical evaluations of doctrines of infallibility seek to highlight errors and contradictions in papal and conciliar teachings. Powell takes a different approach and examines the limitations of papal infallibility as a proposal in religious epistemology, that is, a proposal for how Christians determine and secure their beliefs. In light of this analysis, he outlines a constructive vision for religious epistemology, ecclesial authority, and ecumenical unity. The article concludes by interacting with John Ford’s earlier reviews of this constructive vision.