The Instant of Change in Medieval Philosophy and Beyond ed. by Frédéric Goubier and Magali Roques (review)

This anthology concerns limit-decision problems, chiefly as treated in the fourteenth-century Latin West. A central problem taken up concerns the instant of change: in a change from ø to not-ø such that before instant t there is ø and after t not-ø, at t is there (i) ø, or (ii) not-ø, or (iii) neither, or (iv) both? For medieval thinkers, the answer often depended on what kind of item was at issue. They standardly distinguished permanent items, the whole of which exists simultaneously (substances being a standard example, but also states or forms that are complete in an instant), from successive items, whose parts are non-simultaneous, and gave different type (i) or type (ii) answers in the two cases.

The papers in this volume display the sophisticated variety of medieval thought on this and related puzzles. But as Niko Strobach shows, the puzzles are much older. After distinguishing several problems falling under the head of limit-decision problems, he notes the earliest reference to such a problem in Aristophanes's The Clouds, and then briefly turns to recent concerns in the philosophy of physics.

Particularly fascinating papers concern radical challenges to Aristotelian orthodoxy. Thus, Simo Knuuttila explores Henry of Ghent's treatment of natural generation and creation, arguing that although he does not openly posit contradictions at the instant of change, he divides it into different "signs" having different and incompatible contents, thereby avoiding conceptual contradiction. William O. Duba explores fourteenth-century developments in Landolfo Caracciolo and Hugh of Novocastro. Unlike Henry, both authors expressly posit contradictories holding at the same temporal instant. Norman Kretzmann had dubbed them "quasi-Aristotelians," thinking they had misread the Physics. But, Duba convincingly argues, developing Paul Spade's suggestion, their views derived from Scotus's doctrines of radical contingency and simultaneous causation, doctrines taken up and modified by Hugh and, following Hugh, Landolfo.

Can Laurens Löwe reveals another non-Aristotelian doctrine in Hervaeus Natalis and Durand of Saint-Pourçain, showing how Hervaeus posits, in addition to continuous time, a discrete time in which incompatible forms that completely exist at an instant succeed one another in immediately adjacent instants. Löwe suggests that Hervaeus wished to apply this view to Mary's state of sin and subsequent sanctification. Even so, Hervaeus also retains a standard Aristotelian account for continuous time, attempting to unify the two approaches with a principle relating instants in discrete and continuous time. Durand rejects this principle and holds that permanent entities, including states such as sin and sanctification, exist only in discrete time.

A problem stemming from Aristotle concerns whether the present instant ceases to be when it exists or when it does not. Cecilia Trifogli lucidly presents Walter Burley's defense of the former answer. He avoids contradiction by logical analysis: in the case of instants, "t ceases to be" is analyzed as "t is and immediately after is not"—thus the truth of the analysandum at t does not entail that t does not exist at t. As for Aristotle's original question (when t has first ceased to be?), Trifogli argues that Burley is committed to there being no first instant of t's having ceased to be.

Edith Sylla explores the relation between Burley's treatment of limit problems and Ockham's use of Burley in his Questions on the Physics. Magali Roques suggests that here Ockham no longer reduces all successive entities to permanent ones, and no longer teaches the irrelevance of this distinction to the truth-conditions of propositions about beginning and ceasing. She sees this shift driven by consideration of problems concerning alteration and the generation of the form of a mix.

Gustavo Fernández Walker shows how Nicholas of Autrecourt translates problems of maximal and minimal visible distance into concerns with first and last instants by employing analytical techniques developed at Oxford. These techniques are also deployed in Parisian treatments of Aristotle's remarks...