Covenant and Causality in Pierre d'Ailly

FEW problems are as central to the philosophy and theology of the late Middle Ages as the problem of causality. The acceptance of a causal connection between certain phenomena, where the presence of one follows immediately and invariably upon the presence of another, lies at the heart of the mediaeval understanding of physics and metaphysics, salvation and sacrament. Whether the cause was considered external, according to the Aristotelian principle that omne quod movetur ab alio movetur, or was thought to be internal in the sense of selfmotion, it was assumed that every movement from non-being to being, from potency to act, required a cause which could, with varying degrees of accuracy, be ascertained. Without such a causal connection it seemed impossible to talk about physical laws which regulated the universe upon which man depended, impossible to describe how man comes to know external reality, impossible to construct proofs for the existence of God, and impossible to teach that merit brings reward or that the sacraments produce grace. Both the economy of the natural universe and the economy of salvation depended for their normal explanation on the idea of cause and effect. It is because of the fundamental importance of the principle of causality in mediaeval thought that fourteenth-century discussions of causality, which appeared to alter or abolish efficient causation, seemed so devastating and irresponsible to historians of mediaeval thought. Nominalism in general and William of Ockham and Nicholas of Autrecourt in particular have been credited with an attack on the principle of causality, similar to that later undertaken by Hume, which defined it as nothing more than habit-formed expectation. In spite of some notable scholarly opinion to the contrary, this evaluation has remained and is one of the major judgments according to which Nominalism is considered skeptical and fideistic.1 The history of the critique on causality in the fourteenth century is an enormous topic that has yet to be adequately investigated and is, in any case, far beyond the bounds of a single article.2 The inquiry here will limit itself to one