THOMAS WYLTON ON THE IMMOBILITY OF PLACE Introduction Thomas Wylton's major contribution to natural philosophy is repre- sented by his Quaestiones libri Physicorum, a lengthy commentary per modum quaestionis on the eight books of Aristotle's Physics1. The Quae- stiones were probably written in the years 1301-1304, when Wylton was still master of Arts at the University of Oxford2, that is, before he began his studies of theology at Paris3. Although the Quaestiones have not yet 1. A. MAIER was the first to call attention to Wylton's Quaestiones libri Physicorum in her study «Verschollene Aristoteleskommentare des 14. Jahrhunderts», in: Autour d’Aristote. Recueil d’études de philosophie ancienne et médiévale offert à A. Mansion, Louvain 1955, pp. 521-528. Since Maier's study, the research has focused mainly on the problem of the authorship of the Quaestiones libri Physicorum, which are ascribed by some manuscripts to Thomas Anglicus and not to Thomas Wylton. On the authorship, see A. MAIER, «Verschollene Aristoteleskommentare», pp. 522-528; M. SCHMAUS, «Thomas Wylton als Verfasser eines Kommentars zur Aristotelischen Physik», in: Sitzungsberichte der Bayerischen Akademie der Wissenschaften 9 (1956), pp. 3-11; A. MAIER, «Die Quaestio de velocitate des Johannes von Casale O. F. M.», in: Archivum Franciscanum Historicum 53 (1960), p. 282; Z. KUKSEWICZ, De Siger de Brabant à Jacques de Plaisance. La théorie de l’intellect chez les averroïstes latins des XIIIe et XIVe siècles, Wroclaw-Varsovie-Cracovie 1968, pp. 279-280. 2. On Wylton's biography, see especially, A. B. EMDEN, A Biographical Register of the University of Oxford to A. D. 1500, III, Oxford 1959, pp. 2054-2055. On the dating of Wylton's Quaestiones Physicorum, see Z. KUKSEWICZ, De Siger de Brabant (nt. 1), pp. 176- 177, 181, 279-280. 3. Wylton's activity as master of theology at Paris is relatively better known than his activity as master of arts at Oxford. On Wylton's activity as master of theology, see espe- cially A. MAIER, «Wilhelm von Alwincks Bologneser Quaestionen gegen den Averroismus (1323)», in: Gregorianum 30 (1949), pp. 265-308; W. SENKO, «Tomasza Wiltona Quaestio disputata de anima intellectiva», in: Studia Mediewistyczne 5 (1964), pp. 5-190; Z. KUK- SEWICZ, De Siger de Brabant (nt. 1), pp. 176-201; ID., «De infinitate vigoris Dei des Pariser Averroisten Johannes de Janduno», in: Manuscripta 9 (1965), pp. 167-170; J. ERMATINGER, «John of Jandun in his Relations with Arts Masters and Theologians», in: Arts libéraux et Philosophie au Moyen Age. Actes du quatrième Congrès de Philosophie médiévale, Montréal- Paris 1969, pp. 1181-1183; E. JUNG-PALCZEWSKA, «Jean de Jandun a-t-il affirmé la nature active de l'intellect possible?», in: Mediaevalia Philosophica Polonorum 27 (1986), pp. 15-20; EAD., «Thomas Wilton and his question on the Infinite Power of God», in: Mediaevalia Philosophica Polonorum 32 (1994), pp. 41-56. Wylton's main extant theological work is a Quodlibet, preserved in the manuscript Città del Vaticano, Biblioteca Apostolica ©RTPM 65,1 (1998) 1-39 2 RECHERCHES DE THÉOLOGIE ET PHILOSOPHIE MÉDIÉVALES been edited, a recent investigation of Wylton's position on some tradi- tional problems of Aristotle's Physics has started to shed light on his physical theories and their influence. For instance, the analysis of his views on the ontological status of motion and of time has revealed Wyl- ton's strongly realistic approach to natural philosophy4. It has also shown that he openly rejects Averroes' position on these topics, thereby pointing out that Wylton's reputed Averroism is in need of some qualifications. Furthermore, Wylton's treatment of problems like time and the instant of change exerted a great influence on authoritative XIVth-century commentators, such as John of Jandun and Walter Burley5. Accord- ingly, even these fragmentary results are enough to establish the philo- sophical and historical value of Wylton's Quaestiones libri Physicorum. This paper is devoted to Wylton's position on the immobility of place. Indeed, this is one of the traditional problems of Aristotle's theory of place in Physics IV, a problem for which Aristotle presented no satisfactory solution, in his commentators' view, and that con- sequently became matter of debate both in the Greek and in the Medieval tradition. Wylton devotes a specific question to the problem of the immobility of place (Book IV, q. 6: Utrum locus sit immobilis), which is edited in the second part of this paper6. In the first part, instead, we shall present the content of Wylton's discussion, aiming both at providing a guide to the text of q. 6 and at pointing out the originality and historical importance of Wylton's position. Vaticana, ms. Borgh. lat. 36. A number of new theological questions by Wylton have been most recently discovered by Stephen Dumont. On these new questions and on the other extant theological works by Wylton, see S. DUMONT, «New Questions by Thomas Wylton», in: Documenti e studi sulla tradizione filosofica medievale 9 (1998), pp. 341-381. 4. For Wylton's view on the ontological status of motion, see C. TRIFOGLI, «Thomas Wylton on Motion», in: Archiv für Geschichte der Philosophie 77 (1995), pp. 135-154. I have edited Wylton's questions on this topic in EAD., «Due questioni sul movimento nel Commento alla Physica di Thomas Wylton», in: Medioevo 21 (1995), pp. 51-73. For his view on the ontological status of time and for the edition of the question on this topic, see EAD., «Il problema dello statuto ontologico del tempo nelle Quaestiones super Physicam di Thomas Wylton e di Giovanni di Jandun», in: Documenti e studi sulla tradizione filosofica medievale 1,2 (1990), pp. 491-548. For another aspect of Wylton's theory of time, see EAD., «Thomas Wylton on the Instant of Time», in: A. ZIMMERMANN (ed.), Mensch und Natur im Mittelalter (Miscellanea Mediaevalia 21/1), Berlin-New York 1991, pp. 308-318. 5. For the debate between Wylton and Jandun on the ontological status of time, see C. TRIFOGLI, «Il problema…» (nt. 4). For the influence of Wylton's treatment of the problem of the instant of change on Burley's treatise De primo et ultimo instanti, see EAD., «Thomas Wylton's Question An contingit dare ultimum rei permanentis in esse», in: Medieval Philosophy and Theology 4 (1994), pp. 91-141, especially pp. 137-141. 6. All my references to Wylton's question Utrum locus sit immobilis will be to the crit- ical edition contained in Part II below. THOMAS WYLTON ON THE IMMOBILITY OF PLACE 3 PART I The structure of q. 6 is the following: (i) first Wylton lists some arguments against the immobility of place7, (ii) then he presents three major XIIIth-century «positive» solutions to this problem, i.e., solutions that pretend to show that place is in fact immobile. He rejects them all8, (iii) subsequently he gives a reconstruction of Aver- roes' fragmentary treatment of this problem and he rejects it as well, at least partially9, (iv) he presents his own position and also discusses some objections against it10, (v) finally, he solves the counterargu- ments11. In what follows, (1) we shall first introduce the Aristotelian back- ground of the problem of the immobility of place, thereby clarifying the meaning of the counterarguments found in (i). (2) We shall then explain the main points of the three positive solutions to the problem and of Wylton's refutation of them. (3) Finally, we shall present Wyl- ton's solution, while comparing it with Averroes' position and setting it more generally in the context of the XIIIth- and XIVth-century debate on this problem. 1. The Aristotelian Background In Physics IV.4, Aristotle first defines the place of a body A as the limit of the body B containing A that is in contact with A12. Thus, according to this definition, the place of a ship in a river is the surface of water in contact with the ship. Later in the same chapter, however, Aristotle makes clear that, since this definition is to some extent incomplete, it remains provisional. What needs to be added to it is a requirement that distinguishes place from any container whatsoever. In the follow- ing passage, which leads to the final definition of place, Aristotle argues that the requirement in question is the immobility of place: And, just as a vessel is a mobile place, so place is an immobile vessel. There- fore, when an enclosed thing moves and changes within something that moves, like a ship in a river, it has the surrounding thing serving as a vessel 7. THOMAS WYLTON, In Physicam, IV, q. 6, lin. 2-30. 8. Ibid., lin. 32-139. 9. Ibid., lin. 140-258. 10. Ibid., lin. 259-392. 11. Ibid., lin. 393-440. 12. Aristotle’s Physics. A Revised Text with Introduction and Commentary by D. ROSS, Oxford 1979, IV.4, 212a5-6a. 4 RECHERCHES DE THÉOLOGIE ET PHILOSOPHIE MÉDIÉVALES rather than as a place. But place should be immobile. Therefore, the whole river is rather the place, because the whole is immobile. So the first immobile surface of the surrounding thing, that is place13. This passage, which almost exhausts Aristotle's treatment of the immobility of place, is puzzling in several respects. First, although the difference between an immobile place and a mobile vessel formulated at the beginning of the passage is clear in its abstract formulation, its subsequent illustration with the case of a ship in a river is problem- atic. Since the water surrounding the ship continuously flows, then — Aristotle claims — the place of this ship should rather be identi- fied with the «whole river», which is immobile.