The nomological image of nature: explaining the tide in the thirteenth century

ABSTRACT

The 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. (1) 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. (2) 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, (3) 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.

Acknowledgements

This research was supported by the Israel Science Foundation (grant no. 1622/13): “Roger Bacon (1214–1294) and the Making of the Concept of Law of Nature,” with Giora Hon (Philosophy, University of Haifa) as the Principal Investigator.

Notes

¹ See Edgar S. Laird, ‘Robert Grosseteste, Albumasar and medieval tidal theory’, Isis, 81 (1990), 684–94; David E. Cartwright, Tides: A Scientific History (Cambridge: Cambridge University Press, 1999). Cartwright devotes only a few pages to medieval accounts. Both studies do not mention Albert the Great. See also Pasquale Ventrice, La Discussione sulle maree, tra astronomia, meccanica e filosofia nella cultura veneto-padovana del cinquecento, Memorie della Classe di Scienze Fisiche, Matematiche e Naturali, vol. 34 (Venezia: Isituto Veneto di Scienze Lettere e Arti, 1989), on tide theories in the Renaissance; finally, Pierre Duhem, Le système du Monde. Histoire des Doctrines cosmolgiques de Platon à Copernic, 10 vols (Paris: Hermann, 1913–1959), vol. 9, pp. 7–70.

² Catherine Wilson, ‘From Limits to Laws: The Construction of the Nomological Image of Nature in Early Modern Philosophy’, in Natural Law and Laws of Nature in Early Modern Europe – Jurisprudence, Theology, Moral and Natural Philosophy, ed. by Lorraine Daston and Michael Stolleis (Burlington, VT: Ashgate, 2008), pp. 13–28.

³ See Cartwright, Tides, pp. 8–9.

⁴ See Cartwright, Tides, pp. 8–9.

⁵ See Cartwright, Tides, pp. 13–15.

⁶ See Richard J. Lemay, Abu Ma'shar and Latin Aristotelianism in the Twelfth Century – The Recovery of Aristotle's Natural Philosophy through Arabic Astrology (Beirut: American University of Beirut, 1962), p. XXIX.

⁷ See John D. North, ‘Celestial Influences – the Major Premise of Astrology’, in ‘Astrologi hallucinati’ – Stars and the End of the World in Luther's Time’, ed. by Paola Zambell (Berlin & New York: Walter de Gruyter, 1986), pp. 45–100 (pp. 53–9).

⁸ See Cartwright, Tides, p. 15.

⁹ Gerald recommended Grosseteste for his work at Hereford, see Laird, ‘Robert Grosseteste’, p. 685.

¹⁰ See Rudolf Simek, Heaven and Earth in the Middle Ages – The Physical World before Colombus, trans. by Angela Hall (Woodgridge: The Boydell Press, 1996), p. 101.

¹¹ See Francis J. Carmody, Arabic Astronomical and Astrological Sciences in Latin Translation: A Critical Bibliography (New York: Dover, 1953), pp. 264–7.

¹² I find in the texts no straightforward references to each other's work. However, Bacon surely knew Albert and it is probable that they met at the University of Paris. See Alistair C. Crombie and John D. North, ‘Roger Bacon’, in Dictionary of Scientific Biography, 16 vols, ed. by Charles C. Gillispie (New York: Charles Scribner's Sons, 1970), vol. 1, pp. 377–85 (p. 377). Albert had been most likely the target of Bacon's criticism and scorn, as Jeremiah Hackett reasoned ('The attitude of Roger Bacon to the scientia of Albertus Magnus', in Albertus Magnus and the Sciences – Commemorative Essays 1980, ed. by James A. Weisheipl (Toronto: Pontifical Inst. of Medieval Studies, 1980), pp. 53–72). In his exposition of the Metaphysics, Albert attacked the mathematical understanding of natural beings held by the amici Platonis, whom Weisheipl identifies as Grosseteste, Robert Kilwardby and Roger Bacon (James A. Weisheipl, ‘Albertus Magnus and the Oxford Platonists’, Proceedings of the American Catholic Philosophical Association, 32 (1958), 124–39 (pp. 131–6)). Crombie, on the other hand, argues that Albert quoted at length from Grosseteste's writings on scientific method and optics. See Alistair Crombie, ‘Grosseteste's position in the history of science’, in Robert Grosseteste Scholar and Bishop – Essays in Commemoration of the Seventh Century of his Death, ed. by D. A. Callus (Oxford: Clarendon Press, 1955), pp. 111–12. Whether Grosseteste and Bacon met is not clear. It may be the case that Bacon studied Arts at Oxford around 1227–30, while Grosseteste was still teaching there, or that they met in Paris in 1245, on their way to the council of Lyon (I thank Cecilia Panti for these suggestions). In any event, Bacon mentioned Grosseteste by name, was clearly influenced by him, and had access to his manuscripts. See Alistair C. Crombie, Robert Grosseteste and the Origins of experimental Science 1100 – 1700, (Oxford: Clarendon Press, 1953), p. 139.

¹³ Richard C. Dales, 'The Text of Robert Grosseteste's Questio de fluxu et refluxu maris with an English Translation’, Isis, 57 (1966), 455–74. For the dating of the De fluxu, see James McEvoy, ‘The Chronology of Robert Grosseteste's Writings on Nature and Natural Philosophy’, Speculum, 58 (1983), 614–55 (p. 630). For the attribution of the De fluxu to Grosseteste, see the Appendix, below. Grosseteste wrote two other works in which he attended the problem of tide: the early De impressionibus aeris and the Commentarius in libros Analyticorum Posteriorum Aristotelis, where he discussed the rise and fall of the Nile. I leave these texts aside, for the intent is to focus on a comparison of the three thinkers rather than on different texts of the same author.

¹⁴ Albert the Great, On the Causes of the Properties of the Elements (Liber de causis proprietatum elementorum), trans. by Irven M. Resnick (Milwaukee: Marquette University Press, 2010). On the chronology of this work, see James A. Weisheipl, ‘Albert's Works on Natural Science (libri naturales) in Probable Chronological Order (Appendix 1)’, in Weisheipl, Albertus Magnus and the Sciences, pp. 565–77.

¹⁵ De fluxu et refluxu maris by Grossetste and Liber de causis proprietatum elementorom by Albert received excellent English translations, which I use. Quotations from Opus majus and other texts, lacking a reasonable translation, are followed by the original Latin.

¹⁶ See Duhem, Histoire des Doctrines cosmolgiques, pp. 15–6.

¹⁷ See Duhem, Histoire des Doctrines cosmolgiques, pp. 17–8.

¹⁸ Studies on the development of the concept of laws of nature during the middle ages include, among others, Michael B. Foster, ‘The Christian doctrine of Creation and the rise of Modern Natural Science’, Mind, 43 (1934), 446–68 (continued by two papers published in the same journal in 1935 and 1936); Alistair C. Crombie, ‘The Significance of Medieval Discussions of Scientific Method for the Scientific Revolution’, in Critical Problems in the History of Science, ed. by Marshall Cllaget (Madison: The University of Wisconsin Press, 1959), pp. 79–102; Francis Oakley, ‘Medieval Theories of Natural Law: William of Ockham and the Significance of the Voluntaristic Tradition’, Natural Law Forum 6 (1961), 65–83; John R. Milton, ‘The Origin and Development of the Concept of the “Laws of Nature”’, Archives Europeennes de Sociologie 22 (1981), 173–95; Matthias Schramm, ‘Roger Bacon's Begriff vom Naturgesetz’, in Die Renaissance der Wissenschaften im 12. Jahrhundert, ed. by Peter Weimar (Zurich: Artemis, 1981), pp. 197–209; Eugene M. Klaaren, Religious Origins of Modern Science (Lahman: University Press of America, 1985); Jane A. Ruby, ‘The Origins of Scientific “Law”’, Journal of the History of Ideas, 47 (1986), 341–59; and Friedrich Steinle, ‘From Principles to Regularities: Tracing “Laws of Nature” in Early Modern France and England’, in Natural Law and Laws of Nature in Early Modern Europe – Jurisprudence, Theology, Moral and Natural Philosophy, ed. by Weinert Friedel (Burlington, VT: Ashgate, 2008), pp. 215–32. Studies placing the origin of the concept in the seventeenth century and onwards are not included here. An exception to the tendency to present a sweeping overview is the paper by Schramm, in which he discusses the solution offered by Roger Bacon to the problem of water remaining in the clepsydra in opposition to their natural inclination downwards.

¹⁹ Robert Grosseteste, De fluxu et refluxu maris, in Dales, ‘The Text of Robert Grosseteste's Questio de fluxu 459–74 (p. 468).

²⁰ See Laird, ‘Robert Grosseteste’, p. 686.

²¹ See McEvoy, ‘The Chronology’, p. 652.

²² See McEvoy, ‘The Chronology’, p. 652.

²³ McEvoy (‘The Chronology’, pp. 647–8) dates this work to 1330. Panti (Cecilia Panti, ‘Robert Grosseteste and Adam of Exeter's Physics of Light – Remarks on the Transmission, Authenticity and Chronology of Grosseteste's Scientific Opuscula’, in Robert Grosseteste and his Intellectual Milieu – New Editions and Studies, ed. by John Flood, James R. Ginther and Joseph W. Goering (Toronto: Pontifical Institute of Medieval Studies, 2013), pp. 165–90 (pp. 181–2)) thinks it should be dated earlier, to 1225, since it represents his ‘first steps into the doctrine of light’.

²⁴ Robert Grosseteste, On Light (De luce), trans. by Neal Lewis, in Robert Grosseteste and his Intellectual Milieu, pp. 239–47 (pp. 242–4).

²⁵ Robert Grossetetse, On the Six Days of Creation, I.7.2, trans. by Christopher F. J. Martin (Oxford: Oxford University Press, 1996), pp. 55–6.

²⁶ Robert Grosseteste, ‘De motu corporali et luce’, in Die Philosophichen Werke des Robert Grosseteste, Bischofs von Lincoln, ed. by Ludwig Baur (Munster: Aschendorf, 1912), pp. 90–2 (p. 90).

²⁷ Laird, ‘Robert Grosseteste’, pp. 686–7.

²⁸ Grosseteste, De fluxu, 459: 26.

²⁹ See Aristotle, Physics 8.4, 255a5–18 and 8.6, 258b26–259a9; De caelo 2.7, 289a19–35; Metaphysics 12.5, 1071a14–17.

³⁰ Groseteste, De fluxu, 459: 26–9.

³¹ Robert Grosseteste, ‘De lineis angulis et figuris’, in Baur, Die Philosophischen Werke, pp. 59–65 (p. 60). The English translation, ‘Concerning Lines, Angles, and Figures’, is by David C. Lindberg, in Sourcebook in Medieval Science, ed. by Edward Grant (Cambridge, MA: Harvard University Press, 1974), pp. 385–91.

³² Grosseteste, ‘De lineis’, pp. 62–3.

³³ Light is external in the sense that it has a nature and essence of its own, distinct from the substances made up of elemental matter. In terms of location it is not external to those things, since it is in them as the form of corporeity. It is also found in corporeal bodies, imprisoned in pockets of rarified air, as argued in Grosseteste's explanation of the echo. See Richard W. Southern, Robert Grosseteste – The Growth of an English Mind in Medieval Europe (Oxford: Clarendon Press, 1986), p. 158.

³⁴ On light as an active force and on Grosseteste's metaphysics or philosophy of light, see David C. Lindberg, Theories of Vision from al-Kindi to Kepler (Chicago: Chicago University Press, 1976), pp. 94–102; Klaus Hedwig, Sphera Lucis: Studien zur Inteligibilitat des Seienden im Kontext der mittelalterlichen Lichtspekulation (Munster: Westf., 1980), pp. 119–50; David C. Lindberg, ‘Roger Bacon on Light, Vision, and the Universal Emanation of Force’, in Roger Bacon and the Sciences: Commemorative Essays, ed. by Jeremiah M. G. Hackett (Leiden: Brill, 1997), pp. 243–76.

³⁵ See Grosseteste, On Light, p. 13.

³⁶ This point is noted by Crombie, ‘The significance’, pp. 88–9.

³⁷ Grosseteste, De fluxu, 462: 110–1.

³⁸ For the dating see McEvoy, ‘The Chronology’, 635.

³⁹ Robert Grosseteste, De calore solis, in Baur, Die Philosophichen Werke, pp. 79–84 (p. 83): ‘Relinquitur ergo, quod sol generat calidum per collectionem radiorum. Quod sic patet: Radii solis in perspicuo aeris per naturam densi in eo incorporantur quodammodo; sed radii solis cadentes deorsum super planum terrae vel concavum, vel convexum reflectuntur secundum angulos aequales, ut patet ex ultimo principiorum doctrinae “de Speculis”. Si ergo cadunt radii orthogonaliter, reflectuntur orthogonaliter; et ita radius cadens et reflectens super eandem viam intendit per partes omnino oppositas et est ibi maxima disgregatio’.

⁴⁰ Grosseteste, De fluxu, 463–4: 144–57.

⁴¹ Laird, ‘Robert Grosseteste’, p. 688.

⁴² Grosseteste, De fluxu, 460--1: 77–9.

⁴³ Grosseteste, De fluxu, 461: 82–4.

⁴⁴ See Betsy B. Price, ‘The Physical Astronomy and Astrology of Albertus Magnus’, in Weisheipl, Albertus Magnus and the Sciences, pp. 155–85 (p. 176).

⁴⁵ See Lemay, Abu Ma'shar, p. 64.

⁴⁶ See David Pingree, ‘Abu Mashar Al-Balkhi, Jafar ibn Muhammad’, in Dictionary of Scientific Biography, vol. 1, pp. 32–6 (p. 34).

⁴⁷ Grosseteste, De fluxu, 461: 84–6.

⁴⁸ Grosseteste, De fluxu, 463–4: 141–57.

⁴⁹ Grosseteste, De fluxu, 461–2: 89–101.

⁵⁰ See McEvoy, ‘The Chronology’, p. 633.

⁵¹ Grosseteste, ‘De natura locorum’, in Baur, Die Philosophischen Werke, pp. 65–72 (pp. 69–70).

⁵² Grosseteste, ‘Concerning Lines’, p. 385.

⁵³ Grosseteste, ‘De natura locorum’, p. 66.

⁵⁴ Albert, On the Causes, 1.2.4, 52.

⁵⁵ Albert, On the Causes, 1.2.4, 53.

⁵⁶ Andrew G. Molland, ‘Mathematics in the Thought of Albertus Magnus’, in Weisheipl, Albertus Magnus and the sciences, pp. 463–78 (pp. 468–9).

⁵⁷ Albert, ‘Posteriora analytica’ 1, tr. 3, c.7 (ed. Borgnet 2: 86a), trans. by Molland, ‘Mathematics in the Thought’, p. 468.

⁵⁸ Albert, On the Causes, 1.2.5, 56.

⁵⁹ Albert, On the Causes, 1.2.5, 56.

⁶⁰ Albert, On the Causes, 1.2.5, 57.

⁶¹ Albert, On the Causes, 1.2.5, 57.

⁶² Albert, On the Causes, 1.2.5, 57.

⁶³ Albert, On the Causes, 1.2.4, 53.

⁶⁴ Albert, On the Causes, 1.2.5, 57.

⁶⁵ Albert, On the Causes, 1.2.4, 53.

⁶⁶ Albert, On the Causes, 1.2.4, 53.

⁶⁷ See the explanation by Price, ‘The Physical Astronomy’, p. 176.

⁶⁸ Albert, On the Causes, 1.2.5, 57.

⁶⁹ Roger Bacon, Opus majus, 3 vols, ed. by John H. Bridges (Oxford and Edinburgh, 1897; reprint, Frankfurt: Minerva, 1964), vol. 2, 4.4.6, 139: ‘multiplicatio secundo lineas et angulos determinatos’.

⁷⁰ Roger Bacon, ‘De multiplicatione specierum’ in Roger Bacon's Philosophy of Nature: A Critical Edition, with English Translation, Introduction and Notes, of De multiplicatione specierum and De speculis comburentibus, ed. and trans. by David C. Lindberg (Oxford: Clarendon Press, 1983), pp. 2–3. The same claim also appears in Bacon's Quaestiones supra librum de sensu et sensato 12, in (1905–1940). Opera hactenus inedita Rogeri Baconi, 16 fascs, ed. by Robert Steele (Oxford: Clarendon Press, 1905–1940), fsc 14, 29: ‘omnis enim natura activa sic videtur facere, aut ratione forme substantialis aut alicujus forme accidentalis aut utriusque, que forma non oportet quod sit lux. Frigiditas enim et siccitas vere sunt nature active per quas potest fieri multiplicatio virtutis et speciei’.

⁷¹ Bacon, Opus majus, vol. 2, 4.4.6, 140.

⁷² Bacon, Opus majus, vol. 2, 4.4.6, 140.

⁷³ Bacon, Opus majus, vol. 2, 4.4.6, 140–1: ‘Nam universaliter calor debilis resolvit vapors et non consumit, calor enim solis fortis consumit…’; ‘Et sic de omni virtute agente, cujus est proprium resolvere et consumere’.

⁷⁴ Roger Bacon, ‘Opus tertium’, in Opera quaedam hactenus inedita, ed. by John S. Brewer (London: Longman, Green, Longman and Roberts, 1859), cap. 32, p. 111: ‘Et ideo non possunt dari causae rerum naturalium nisi per vias geometriae.…’ For a fuller discussion of the place of mathematics in explanations of natural phenomena in Grosseteste, Albert and Bacon, see David C. Lindberg, ‘On the Applicability of Mathematics to Nature: Roger Bacon and his Predecessors’, The British Journal for the History of Science, 15 (1982), 3–25.

⁷⁵ Albert, On the Causes, 1.2.5, 65.

⁷⁶ Bacon, Opus majus, vol. 2, 4.4.6, 141: ‘aut per radios lucis, aut per radios suae naturae substantialis, aut per utrosque’.

⁷⁷ See Bacon, ‘De multiplicatione’, 1.1, 5.

⁷⁸ If the suggestions that De fluxu was written by a different author were correct (see footnote 13 above and appendix below), then this would not be a matter of Grosseteste's change of mind but a matter of different authorship. We might never know for certain. In any event, the principle of connaturality was borrowed directly from the text by Albumasar, and it may be the case that Grosseteste did not make use of it in his other texts.

⁷⁹ Albert, On the Causes, 1.2.6, 60.

⁸⁰ Albert, On the Causes, 1.2.5, 57.

⁸¹ Groseteste, De fluxu, 464: 148–50. See also Laird, ‘Robert Grosseteste’, p. 689.

⁸² Albert, On the Causes, 1.2.4, 53–4.

⁸³ Albert, On the Causes, 1.2.7, 65.

⁸⁴ Albert, On the Causes, 1.2.6, 59.

⁸⁵ Albert, On the Causes, 1.2.8, 70–1.

⁸⁶ See Laird, ‘Robert Grosseteste’, p. 685.

⁸⁷ Grosseteste, De fluxu, 465: 5–8; Albert, On the Causes, 1.2.6, 60.

⁸⁸ Grosseteste, De fluxu, 466: 21–6; Albert, On the Causes, 1.2.6, 60.

⁸⁹ Grosseteste, De fluxu, 466: 48–9; Albert, On the Causes, 1.2.6, 62.

⁹⁰ Grosseteste, De fluxu, 466: 41–7; Albert, On the Causes, 1.2.6, 61.

⁹¹ Albert, On the Causes, 1.2.6, 61–2.

⁹² Grosseteste, De fluxu, 466: 27–32.

⁹³ Grosseteste, De fluxu, 465–6: 15–20.

⁹⁴ Grosseteste, De fluxu, 466: 50–5.

⁹⁵ Albert, On the Causes, 1.2.6, 60.

⁹⁶ Albert, On the Causes, 1.2.6, 60.

⁹⁷ See, for example, Opus majus, 4.2.2, vol. 1, 112: ‘perpendicularis fortiori est et brevior, et ideo natura operator meliori modo super eam’; Opus majus, 4.3.1, vol. 1, 120: ‘Natura ergo, ut dictum est, forties operator super lineam rectam quam super curvam, quia brevior est, et minus facit patiens distare ab agente.’

⁹⁸ Grosseteste, De fluxu, 462: 108–14.

⁹⁹ Laird, ‘The Authorship’, pp. 587–8.

¹⁰⁰ Grosseteste, ‘De natura locorum’, 70: ‘Et ideo reflexio radiorum solvit istud, quoniam radii lunares multiplicantur ad caelum stellarum, quod est corpus densum. Ideoque per medium eius non possumus videre caelum, quod est valde luminosum, sicut dicit Alpetragius et Messalahe. Et alii radii reflexi cadunt in quartam oppositam ad angulos aequales’.

¹⁰¹ See Duhem, Histoire des doctrines cosmolgiques, p. 33.

¹⁰² Bacon, Opus majus, vol. 2, 4.4.6, 141: ‘et sic virtus lunae est directa in quarta una et ejus reflexio in eodem tempore in quarta opposita’.

¹⁰³ Bacon, Opus majus, vol. 2, 4.4.6, 141.

¹⁰⁴ See Julio Samsó, ‘Bit˙rūjī: Nūr al‐Dīn Abū Ish˙ āq [Abū Jaʿfar] Ibrāhīm ibn Yūsuf al‐ Bit˙rūjī’, in The Biographical Encyclopedia of Astronomers, ed. by Thomas Hockey et al. (New York: Springer, 2007), pp. 133–4. For Alpetragius’ text, see Francis J. Carmody, Al‐Bit˙rūjī: De motibus celorum. Critical edition of the Latin translation of Michael Scot (Berkeley: University of California Press, 1952), and Bernard R. Goldstein, Al‐Bit˙rūjī: On the Principles of Astronomy, 2 vols (New Haven: Yale University Press, 1971). For his influence on Albert the Great, see Angel Cortabarría, ‘Deux sources de S. Albert le Grand: Al‐Bitruji et al‐Battani’, Mélanges de l’Institut dominicain d’etudes orientales, 15 (1982), 31–52.

¹⁰⁵ Grosseteste, De fluxu, 460: 40–2.

¹⁰⁶ Albert, On the Causes, 1.2.7, 63–4.

¹⁰⁷ Bacon, Opus majus, vol. 2, 4.4.6, 139.

¹⁰⁸ Grosseteste, De fluxu, 460: 45–60.

¹⁰⁹ Grosseteste, De fluxu, 460: 65–69.

¹¹⁰ See Alistair C. Crombie, Robert Grosseteste and the Origins of Experimental Science (Oxford: University Press, 1953), p. 87; Laird, ‘Robert Grosseteste’, p. 687.

¹¹¹ Albert, On the Causes, 1.2.3, 47–8.

¹¹² Albert, On the Causes, 1.2.3, 48–50.

¹¹³ Albert, On the Causes, 1.2.7, 64.

¹¹⁴ Albert, On the Causes, 1.2.7, 64.

¹¹⁵ Albert, On the Causes, 1.2.7, 65.

¹¹⁶ Bacon, Opus majus, vol. 2, 4.4.6, 139–40.

¹¹⁷ Bacon, Opus majus, vol. 2, 4.4.6, 140.

¹¹⁸ Grosseteste, ‘De natura locorum’, 70: ‘cessante causa cessat effectus’. When the cause ceases, so does the effect; when the cause exists in one mode, nature acts in one mode. Albert, On the Causes, 1.2.7, 64: ‘when their cause exists in one mode, the works of nature are in one mode’; For Bacon, see n. 119 below.

¹¹⁹ In De luce Grosseteste identified light with the first form of corporeity, that makes it a form inherent in every corporeal thing. In this way he posited a universal source of activity inherent throughout the material world. Now, nature can be described in general statements about the nature and behavior of light, rather than by defining the nature of each species and genus separately. But this is a subject for another paper.

¹²⁰ Albert, On the Causes, 1.2.7, 65.

¹²¹ Grosseteste, ‘De natura locorum’, 70: ‘ideo aquae maris tunc naturaliter recurrunt in locum suum ne fiat vacuum’.

¹²² For the unifying role of astrology, see Lemay, Abu Ma'shar, p. XXVI.

¹²³ Leen Spruit, ‘Albert the Great on the Epistemology of Natural Science’, in Erfahrung und Beweis – Die Wissenschaften von der Natur im 13. Und 14. Jahrhundert – Experience and Demonstration – The Sciences of Nature in the 13^th and 14^th Centuries, ed. by Alexander Fidora and Matthias Lutz-Bachmann (Berlin: Akademie Verlag, 2007), pp. 61–76 (p. 63).

¹²⁴ William A. Wallace, ‘Albertus Magnus on Suppositional Necessity in the Natural Sciences’, in Weisheipl, Albertus Magnus and the Sciences, pp. 103–28 (p. 113).

¹²⁵ Roger Bacon, Communia naturalium 1.1.2.2, in Opera hactenus inedita,16 vols, ed. by Robert Steele and Ferdinand M. Delorme (Oxford: Typographeo Clarendoniano, 1909–40), vol. 2, p. 22. ‘quod idem facit agens in quodcunque agat, ut ignis sive agat in lignum sive in tactum, quia agit per naturam et ideo agit uno modo’. See also ‘De multiplicatione specierum’ 1.1, in Roger Bacon's Philosophy of Nature: A Critical Edition, with English Translation, Introduction and Notes, of De multiplicatione specierum and De speculis comburentibus, ed. and trans. by David C. Lindberg (Oxford: Clarendon Press, 1983), p. 19: ‘But a natural agent possesses neither will nor the ability to deliberate, and therefore it acts uniformly […] since nature and natural mode have the same mode [of action]’.

¹²⁶ Ruby, ‘The Origins’, p. 293.

¹²⁷ Crombie, ‘The Significance’, pp. 87–8.

¹²⁸ Callus, Robert Grosseteste, p. 22; McEvoy, ‘The Chronology’, p. 630; Laird, ‘Robert Grosseteste’, pp. 684–94.

¹²⁹ In ‘The Authorship of the Questio de Fluxu et Refluxu Maris Attributed to Robert Grosseteste’, Speculum, 37 (1962), 582–8, Richard C. Dales argued for the authorship of Grosseteste. However, in a later paper (‘Adam Marsh, Robert Grosseteste, and the treatise on the tides’, Speculum, 52 (1977), pp. 900–1), he accepted the claim that there are equal evidence for both Grosstetse and Marsh as authors.

¹³⁰ Panti, ‘Robert Grosseteste’, pp. 168–80. Panti notes that her new claim for ascription follows a hint suggested by Southern, Robert Grosseteste, pp. 122–3.

¹³¹ Panti, ‘Robert Grosseteste’, pp. 175–6.

¹³² Panti, ‘Robert Grosseteste’, pp. 173–80.

¹³³ See Panti, ‘Robert Grosseteste’, p. 170 and Southern, Robert Grosseteste, p. 123.

¹³⁴ Laird, ‘The Authorship’, pp. 587–8.