Yael Kedar

Roger Bacon’s conception of place anticipates the fourteenth-century development of indivisibilist theories of place and distance as geometrical magnitudes, while breaking the often-assumed association between indivisibilism and non-Aristotelian conceptions of place. This paper traces three key moments in Bacon’s view of place: (1) an early endorsement of place as three-dimensional; (2) a critique of the Aristotelian notion of place as a container, leading to a preference for an ‘improper’ definition of place in natural philosophy; and (3) the formulation of a new geometrical definition within mathematical and astronomical contexts. The third formulation of place as “space around a point” shifts spatial analysis toward geometry, while preserving physical continuity by allowing several bodies to share the same place. By detaching place from a specific containing body and insisting that several bodies can share one and the same place, Bacon transformed place from a relational property into a quasi-independent feature of the physical world.

This study examines Bacon’s critique of the Unity of Matter Thesis (UMT) as articulated in his Opus maius. In this work, he refutes UMT using mathematical reasoning, particularly targeting its implication of material holenmerism. He argues that if prime matter were numerically identical across all things, it would possess infinite potency, which in turn necessitates an infinite essence. The latter would mean equating matter with God, a heretical conclusion. Bacon focuses particularly on the link between infinite potency and essence. He advances three “geometrical” demonstrations that reject the idea of infinite potency of matter. These demonstrations appeal to the paradox of unequal infinities to show that if actual infinities exist, some would be greater than others, violating mathematical principles. Beyond their specific use in discussing UMT, Bacon’s geometrical demonstrations, modelled after the Euclidean proof, not only exemplify his commitment to “mathematical epistemology” in metaphysics, but also prefigure later attempts to replace logic with mathematics.

This study examines Bacon’s critique of the Unity of Matter Thesis (UMT) as articulated in his Opus maius. In this work, he refutes UMT using mathematical reasoning, particularly targeting its implication of material holenmerism. He argues that if prime matter were numerically identical across all things, it would possess infinite potency, which in turn necessitates an infinite essence. The latter would mean equating matter with God, a heretical conclusion. Bacon focuses particularly on the link between infinite potency and essence. He advances three “geometrical” demonstrations that reject the idea of infinite potency of matter. These demonstrations appeal to the paradox of unequal infinities to show that if actual infinities exist, some would be greater than others, violating mathematical principles. Beyond their specific use in discussing UMT, Bacon’s geometrical demonstrations, modeled after the Euclidean proof, not only exemplify his commitment to “mathematical epistemology” in metaphysics, but also prefigure later attempts to replace logic with mathematics.

The paper argues that Roger Bacon adhered to a unique form of geometrical atomism, according to which elemental matter can be analysed into cubic (when at rest) or pyramidal (when in motion) portions. Bacon addressed geometrical atomism from the perspective of the Aristotelian review, using his interpretation of Aristotelian principles to render the theory plausible. He was mostly concerned with solving the contradiction between the angular shapes of the portions and the shape of the elemental spheres. His motivation for doing so, I argue, was his conviction in the applicability of geometry onto natural philosophy, and his goal was to render matter capable of geometrical analysis. In this way, he was convinced, geometrical properties can be considered efficient causes of matter’s spatial formation and motion.

In Posterior Analytics 1.13, Aristotle introduced a distinction between two kinds of demonstrations: of the fact (quia), and of the reasoned fact (propter quid). Both demonstrations take a syllogistic form, in which the middle term links either two facts (in the case of quia demonstrations) or a proximate cause and a fact (in the case of propter quid demonstrations). While Aristotle stated that all the terms of one demonstration must be taken from within the same subject matter, he admitted some exceptions in which the fact and the reasoned fact are instantiated by terms from different sciences, as when mathematics provides the reason and another science the empirical fact. This was the methodological foundation of the “mixed sciences”, a subject of varying interpretations in the thirteenth century. Roger Bacon (C. 1220–1292), adhering to Robert Grosseteste’s (C. 1168–1563) commentary on Posterior Analytics, presented a unique interpretation of this exception. He replaced propositional demonstrations with geometrical considerations and diagrams, thus producing geometrical arguments for theorems in natural philosophy. I focus on Bacon’s propter quid arguments, as applied in three case studies: (1) the heat caused by a body moving to its natural place; (2) the motion of the scale; (3) and the contraction of water. Based on an analysis of these demonstrations, I argue that Bacon’s interpretation of propter quid demonstration reflects his application of a scientific methodology that imbues geometrical objects with causal power over material bodies.

The idea that nature is governed by laws and that the goal of science is to discover and formulate these laws, rose to prominence during the Scientific Revolution of the seventeenth century. It was manifestly held by the most significant actors of that revolution such as Galileo, Descartes, Kepler, Boyle, and Newton. But this idea was not new. In fact, it made an appearance in the Middle Ages, and it is likely to have emerged already in Antiquity.1In this paper we pay close attention to the concept of law of nature in the writings of Roger Bacon, the outspoken Franciscan who promoted experimental science. We will be using Bacon as a test case to show that long before the...

The paper examines Roger Bacon’s use of the concept virtus in the Communia naturalium and De multiplication specierum. It focuses on the roles which virtus and species play as vehicles of causality in the inanimate realm. It analyses the distinct functions played by virtus in the motion of celestial spheres, the power of natural place, the attraction of iron to magnet, and the universal nature. The analysis concludes that virtus is an efficient power, a feature of form, capable of causing local motion and instigating natural processes. Species is matter’s response to the stimulation made by virtus through which every natural action, to the exclusion of local motion, is made. Species is a non-efficient power, an ‘appetite’ internal to matter. It is an expression of matter’s inherent inclination to promote and perfect itself, the result of matter’s ‘active potentiality’.

The Philosophy and Science of Roger Bacon offers new insights and research perspectives on one of the most intriguing characters of the Middle Ages, Roger Bacon. At the intersections between science and philosophy, the volume analyses central aspects of Bacon's reflections on how nature and society can be perfected. The volume dives into the intertwining of Bacon's philosophical stances on nature, substantial change, and hylomorphism with his scientific discussion of music, alchemy, and medicine. The Philosophy and Science of Roger Bacon also investigates Bacon's projects of education reform and his epistemological and theological ground maintaining that humans and God are bound by wisdom, and therefore science. Finally, the volume examines how Bacon's doctrines are related to a wider historical context, particularly in consideration of Peter John Olivi, John Pecham, Peter of Ireland, and Robert Grosseteste. The Philosophy and Science of Roger Bacon is a crucial tool for scholars and students working in the history of philosophy and science and also for a broader audience interested in Roger Bacon and his long-lasting contribution to the history of ideas.

did roger bacon and peter john olivi ever meet? We suggest a positive answer to this question. After he became a Franciscan in 1257, Roger Bacon spent ten years at the Franciscan Paris convent. In those years he wrote the De multiplicatione specierum —his most thought-out piece—the Opus majus, Opus minus, and Opus tertium, which he completed by early 1268. It is not clear whether Bacon returned to England after 1268, or remained in Paris until 1280.1 Peter John Olivi wrote the Summa questions in several phases.2 According to Sylvain Piron's chronology, Olivi's questions on Physics should be dated before 1270, and his theory of...

Plotinus resolved the paradox of the immanent transcendence, characterizing the relation between the One and the universe, through his theory of the two energeiai. According to this doctrine, all existents have an internal activity and an external activity: the internal activity comprises the true essence and substance of each being; the external activity is emitted outwards as its image. The source of the emission is thus present in the lower layer of being by virtue of its manifold images. The prominence given to light in elucidating this solution led to a distinction between two types of lights: an original light, corresponding to the internal energeia of every existent, and a secondary light, which is the outflow and image of the first light, existing outside of the luminous body.This paper demonstrates the striking similarity between these two Plotinian lights and the concepts of lux and lumen developed by two thirteenth-century philosophers: Robert Grosseteste and Albertus Magnus. Moreover, the paper contends that the purpose of these two medieval concepts of light was identical to what Plotinus had in mind when he first made the distinction: to account for the relation between the one and the many.Keywords: Plotinus; Albertus Magnus; Robert Grosseteste; Light; Lux; Lumen.

ABSTRACTThe paper examines the relevance of the nomological view of nature to three discussions of tide in the thirteenth century. A nomological conception of nature assumes that the basic explanatory units of natural phenomena are universally binding rules stated in quantitative terms. Robert Grosseteste introduced an account of the tide based on the mechanism of rarefaction and condensation, stimulated by the Moon's rays and their angle of incidence. He considered the Moon's action over the sea an example of the general efficient causality exerted through the universal activity of light or species. Albert the Great posited a plurality of causes which cannot be reduced to a single cause. The connaturality of the Moon and the water is the only principle of explanation which he considered universal. Connaturality, however, renders neither formulation nor quantification possible. While Albert stressed the variety of causes of the tide, Roger Bacon emphasized regularity and reduced the various causes producing tides into forces. He replaced the terminology of ‘natures’ by one of ‘forces’. Force, which in principle can be accurately described and measured, thus becomes a commensurable aspect of a diverse cosmos. When they reasoned why waters return to their place after the tide, Grosseteste argued that waters return in order to prevent a vacuum, Albert claimed that waters ‘follow their own nature’, while Bacon held that the ‘proper force’ of the water prevails over the distant force of the first heaven. I exhibit, for the thirteenth century, moments of the move away from the Aristotelian concerns. The basic elements of these concerns were essences and natures which reflect specific phenomena and did not allow for an image of nature as a unified system. In the new perspective of the thirteenth century the key was a causal link between the position of the Moon and the tide cycle, a link which is universal and still qualitative, yet expressed as susceptible to quantification.