Godfrey of Fontaines and the Act-Potency Axiom

Godfrey of Fontaines and the Act-Potency Axiom* JOHN F. WIPPEL IN RECENTYEARSthere has been considerable interest on the part of students of the history of medieval philosophy in the axiom or principle that whatever is moved is moved by another. For certain medieval thinkers this principle is not to be limited to the realm of purely physical change but applies to every reduction from potency to act. All such change implies dependence on some distinct source or cause. So understood this principle functions as an indispensable step in Thomas Aquinas' well known "first way" or first argument for God's existence (Summa theologiae I, 2, 3). It enters into the efforts of many thirteenth century writers to account for the causality involved in human intellection and volition in particular and for the efficient causality of accidental being in general. At the same time, many were aware of difficulties that appear to militate against its universal application. On the physical level, for instance, how is one to account for apparent instances of self-motion such as the cooling of hot water, the motion of falling bodies, projectile motion, or the movement of animals? On a psychological and metaphysical plane, to what extent can this principle be applied to acts of human intellection? Can it be reconciled with the apparent self-motion involved in acts of human volition and, according to many, required for human freedom? Some, as will be seen below, were so impressed by certain of these difficulties that they would limit application of the principle to matters of purely physical causality, allowing for exceptions in the case of spiritual action such as volition. A Duns Scotus would restrict it even more, denying that it applies to certain types of physical change. Others insisted, however, that this principle must apply to every reduction from potency to act, to every genuine change, all apparent difficulties notwithstanding. One outstanding advocate of this view was the late thirteenth century philosopher-theologian, Godfrey of Fontaines. 1 * I wish to express my gratitude to the National Endowment for the Humanities for the Younger Humanist Fellowship that made this study possible. i For a study of this principle in Thomas Aquinas of. J. A. Weisheipl, "The Principle Omne quod movetur ab alio movetur in Medieval Physics," Isis, 56 (1965), 26-45. On this in Duns Scotus el. R. Effler,.~ohn Duns Scotus and the Principle "Omne quod rnovetur ab alio [299] 300 HISTORY OF PHILOSOPHY Before examining Godfrey's views on this axiom as such, certain more general features of his metaphysics of act and potency should be noted. Thus in Q[uodlibet ] 8, q[uestion] 3 he divides real being (esse verum et reale) into being in potency and being in act. Being in potency is being only in terms of its causes, while being in act is such according to its own nature and completed form. 2 In Q 14. q. 5 he distinguishes two ways in which potency and act may be correlated. By potency one may mean a subject that is perfected by its form and by act the form that perfects it. (We might describe this as act and potency considered statically, as intrinsic coprinciples of a composite entity,) On the other hand, by being in potency one may mean that something does not enjoy being in the nature of things according to its own proper entity but only in virtue of something else, for instance, an extrinsic cause that can bring it into bzing. By being in act he will then mean that it does enjoy such being in the nature of things in terms of its movetur" (St. Bonaventure, N.Y., 1962), as well as the interesting review of the same by F. Van Steenberghen, Journal of the History of Philosophy, 9 (1971), 90-92. For general introductions to Godfrey's life and career as well as for doctrinal summaries cf. M. De Wulf, Un thdologien-philosophe du XIII e si~cle. Etude sur la vie, les wuvres et l'influence de Godefroid de Fontaines (Brussels, 1904); R. Arway, "A Half Century of Research on Godfrey of Fontaines," The New Scholasticism, 36 (1962), 192-218. For Godfrey's...