Within 150 years from the death of Charlemagne in A.D. 814, much of Western Europe had fallen into anarchy created by the private wars of feudal outlaws. From about the year 1000, representatives of the church joined with a few secular lords to see what they could do about this parlous situation. Their response was to seek a "Peace of God" by excommunicating bandits who violated churches, beat up unarmed clergy, or stole the livestock of the poor, and by forcing warring subjects to accept formal terms of peace with each other. Although the "Peace of God" did not bring the fractious warfare of the middle ages to a halt, the initiatives did make a difference. Guided both by self-interest in protecting its own property and by altruism in seeking to protect the powerless, the Western church applied the gospel practically in a destructive, unruly environment.
Because institutional churches do not today have much purchase in the academy, the chances for a Peace of God being imposed on disputes concerning the nature and practice of historical knowledge are slim. Moreover, considering just how counterproductive efforts by churches to speak authoritatively about intellectual questions often turn out to be, it is probably the course of wisdom for modern ecclesiastical organizations to seek subtle rather than overt forms of intellectual influence. Still, the laudable record of the medieval church in providing at least some relief from bitter strife does offer encouragement to think about how classical Christian faith might mediate battles over the practice of history—even if warring factions of objectivists, multiculturalists, traditionalists, postmodernists, patriots, pragmatists, along with all those who employ history to defend the special claims of special populations, do not seem eager for a Peace of God.
One can imagine two kinds of reasoning leading toward such a goal—an indirect means appealing to the moral common sense of those who pursue historical knowledge, and a direct means applying biblical and classically Christian norms straightforwardly.
Most contemporary writing on historical knowledge does not have much time for God, but some of it is unusually helpful nonetheless. From the bountiful harvest represented in recent books, one recurring theme can be related to the conclusions of Scottish philosophers in the second half of the eighteenth century who were deeply shaken by the skeptical conclusions of David Hume. Working from John Locke's depiction of knowledge as human reflection on ideas of sense or memory, Hume concluded that if all human knowledge is thus based on ideas, we must admit that we have no means of telling whether or not our ideas correspond with actual states of being. We may need to continue living by conventions that postulate the existence of an external world—as well as by conventions concerning regular connections between causes and effects, and also by reasoning about causes and effects leading to the postulation of a First Cause who got things going. But we certainly have no way of demonstrating that these postulations are in any traditional sense "true."
The response of Hume's Scottish interlocutors, especially Thomas Reid, was to suggest that Hume might be right about our inability to demonstrate mathematically the reality of much that humans take for granted. Nonetheless, they went on to say, since it is impossible to live—since, in fact, it is impossible even to raise Hume's kind of skeptical questions—without assuming that the sensations common to all humanity actually do reflect a real world corresponding approximately to those sensations, then we possess a strong, prima facie case for the truthfulness of those conventions. This "common sense" case may not be theoretically airtight, but it is conclusive nonetheless since it would be impossible for us even to function as human beings if it were not true. For common-sense realists like Thomas Reid, and even more for those who evoked his name in the United States and Canada, such arguments were also used for shoring up threatened proofs for the existence of God.





