, Volume 20, Issue 1, pp 185–190

The middle ages and modern science

James Hannam: God’s philosophers: How the medieval world laid the foundations of modern science. London: Icon Books, 2009, xi+435 pp, £17.99 HB


    • Department of History and Philosophy of Science, Goodbody HallIndiana University
Essay Review

DOI: 10.1007/s11016-010-9438-8

Cite this article as:
Grant, E. Metascience (2011) 20: 185. doi:10.1007/s11016-010-9438-8

To the overwhelming majority of its readers, the title of James Hannam’s book will appear to be a contradiction in terms. Whatever their educational backgrounds, most people would have been exposed to such negative descriptions of the Middle Ages that they will very likely regard the terms, or expressions, “medieval world” and “foundations of modern science” as either lacking any possible historical connection, or will assume they are the butt of a literary joke. But James Hannam rightly rejects this grossly distorted interpretation of the Middle Ages and declares (p. 5) that “recent research has shown that the Middle Ages was a period of enormous advances in science, technology and culture.” Although one has to qualify what “advances in science” signifies, there can be no doubt that “enormous advances” were made in technology. As Hannam explains, some of the advances between AD500 and 1500 involved the further development of inventions that originated in the Far East (the compass, paper, printing, stirrups, and gunpowder) and many that were unique to medieval Western Europe (spectacles, the mechanical clock, the windmill, the blast furnace, and others).

God’s Philosophers is very well written and a delight to read. The book contains twenty-one chapters and a conclusion. The first twelve chapters are devoted to the Middle Ages; the last nine chapters consider the Renaissance and Reformation, with Galileo as the major subject of the final three chapters (19–21). In a brief, but important, conclusion, titled “A Scientific Revolution?”, Hannam explains that four cornerstones (p. 338) laid the foundations of modern science: institutional, technological, metaphysical, and theoretical. He presents numerous illustrations for each of these categories and argues persuasively that the Middle Ages laid the foundations for early modern science, a view I have held for some years.

Hannam includes a number of very useful aids to the reader. In addition to the usual end notes and index, he also includes a brief section titled “Suggestions for Further Reading” (343–345); a very helpful “Timeline” (345–347); an alphabetical “List of Key Characters” (349–358), which identifies most of the figures mentioned in the volume and supplies their birth and death dates, as well as very brief bits of information about each of them; and a lengthy “Bibliography of Works Cited” (395–420).

But for what class of readers has Hannam written his book? He indicates the category of readers who were foremost in his mind when, in his “Suggestions for Further Reading,” he declares (p. 343): “the books recommended in this section are intended as possible next steps for non-academic readers wishing to explore some of the issues raised in this book.” He again emphasizes the non-academic reader when he cites David C. Lindberg’s, The Beginnings of Western Science (second edition; University of Chicago Press, 2007). Although Hannam regards Lindberg’s book as “an excellent introduction covering both ancient and medieval natural philosophy”, he adds: “unfortunately, it is very obviously a textbook for university students and as a result rather dry.” But is there a class of possible non-academic readers who would be interested in medieval natural philosophy? Does “non-academic” reader mean a person who has not attended a college or university, but who might nevertheless have an interest in medieval natural philosophy? Are there such people?

Whether or not such a group of potential readers exists, Hannam has written his book to appeal to their imagined interests. He enriches his narrative by deliberately expanding the range of themes and topics to embrace descriptions of everyday life, as well as biographical information about numerous figures relevant to science, natural philosophy, and technology. In chapter 10 (“The Clockmaker: Richard of Wallingford”), we find a vivid example of Hannam’s unusual approach. Although the chapter describes the invention and use of mechanical clocks—and especially about the clock Richard of Wallingford built—there is much else besides clocks. Indeed, there is much more about Wallingford’s life than about his clock. Moreover, in a section titled “Oxford University and the Foundation of Cambridge” (153–156), we learn (p. 154) that at medieval universities, “Drunkenness, violence and prostitution were facts of life, with the students acting as both the victims and the instigators.” With this as background, we are informed that, in 1209, troubles occurred in Oxford as a result of the murder of a young woman, which led to riots and lynchings. Teaching ceased at Oxford University for five years, during which time some Oxford masters and students migrated to Cambridge and established Cambridge University. In Chapter 15 (“The Polymaths of the Sixteenth Century”), Hannam devotes a section to “Cardan’s Family Problems” (pp. 243–246) where he relates the problems Jerome Cardan (or Girolamo Cardano) had with his two sons, Aldo, who “was a thief and a violent ruffian,” and Giovanni, who was executed for murdering his wife. In most chapters, Hannam provides analogous information on numerous themes and individuals. These unusual descriptions of various aspects of contemporary life in virtually every chapter make Hannam’s account extremely interesting and engaging.

In dealing with the history of science itself, Hannam ranges over major topics, in mathematics, astronomy, physics, medicine, and the occult sciences of alchemy and astrology. In his chapter on medicine, Hannam declares (p. 264) that, with the exception of small pox vaccinations, “the history of medicine until the mid-nineteenth century… is a history of failure.” In the chapter on medieval medicine, Hannam, in his usual, fascinating manner, sets up his discussion by suggesting to the reader (pp. 109–110):

Place yourself in Paris in 1300. The narrow streets are full of students, craftsmen and beggars. Occasionally, moving through the throng, you might catch sight of a priest or one of the brightly attired administrators attached to the royal court. You hardly care because you are sick. You have had a headache that has grown steadily worse. It keeps you awake all night and now your vision is becoming blurred. What to do?

Hannam identifies three options for this sick individual (p. 110): “the church, the local healer, or a qualified doctor.” He then describes how each might treat their potential patient.

Other chapters also include interesting accounts of relevant scientific activity. In Chapter 11 (“The Merton Calculators”), Hannam discusses Bradwardine’s “law of motion”; descriptions of falling bodies in a vacuum; how a weighted body would be affected if it were dropped through a hole drilled in the earth; and, finally, the mean speed theorem, as expounded by William Heytesbury (ca. 1313–1373). In Chapter 12 (“The Apogee of Medieval Science”), Hannam adds more about the mean speed theorem (as presented by Nicole Oresme) and also describes medieval discussions of the earth’s possible axial rotation (by John Buridan and Nicole Oresme) and Albert of Saxony’s description of the trajectory of a cannon ball. Hannam presents Buridan’s reason for rejecting the earth’s axial rotation (p. 186), but omits to explain that Buridan did not believe in the earth’s absolute immobility. He argued that the earth moves with small rectilinear movements as its center of gravity constantly changes and seeks to coincide with the geometric center of the universe (Grant 2007: 199–200).

Although this engaging book is more likely to be widely read by a much broader audience than would be usual for a more scholarly, more narrowly based book, there are difficulties with some of the claims made, as well as with what the author included and omitted. A major difficulty appears in the chapter I have just described. The final section of this chapter (“The Apogee of Medieval Science”) is titled: “The Decline of Medieval Science” (194–195). Here, Hannam inquires why the advanced ideas and concepts developed in medieval science by the likes of John Buridan and Nicole Oresme were not further advanced by their successors. His answer is the Black Death, “the deadly incursion that stopped all of Europe in its tracks…” (p. 195). By the time the scholars of Europe recovered, “they would discard almost the entire legacy of medieval philosophy,” which included natural philosophy. This is an untenable position. It ignores the Protestant Reformation and the influx of new Greek scientific texts previously unknown in the medieval West. But above all, it overlooks the fact that more universities were founded in Western Europe between 1350 and 1500—approximately 47—than between 1200 and 1349—approximately 30 (de Ridder-Symoens 1992: 62–65). This could not have happened if the plague had had the impact proclaimed by Hannam.

The title of Chapter 6—“How Pagan Science was Christianised”—is unfortunate because it conveys a very misleading sense of the historical relationship between science—that is, natural philosophy—and medieval Christianity. There is no doubt that natural philosophy was used to interpret theology—often playing a role as “handmaiden to theology”—but theology had only a minor influence on natural philosophy. Hannam cites Albert the Great (Albertus Magnus) and Thomas Aquinas as playing the most fundamental roles in this Christianization process. But pagan science was never “Christianised,” and certainly not by Albert and Thomas. At the very beginning of his commentary on Aristotle’s Physics—a commentary that his Dominican brothers had requested—Albert informs his fellow Dominicans that if he had any opinion of his own, “this would be proffered by us (God willing) in theological works rather than in those on physics.” In effect, Albert says that he will not intrude theology into a work on natural philosophy. In a similar vein, Thomas Aquinas replied to questions by a Dominican colleague with the remark that “I don’t see what one’s interpretation of the text of Aristotle has to do with the teaching of the faith.” Vernon Bourke, a scholar of Thomas’s thought, was convinced that Aquinas did not feel he was “required to make Aristotle speak like a Christian” and that Thomas undoubtedly “thought that a scholarly commentary on Aristotle was a job by itself, not to be confused with apologetics or theology.”1 Indeed, medieval Christianity’s monumental contribution to the development of science and natural philosophy was to accept them as independent disciplines to be studied for their own sakes and for the advancement of knowledge. Natural philosophy was never Christianized, but it is no exaggeration to say that theology was “Aristotelianised.” Theologians routinely used natural philosophy and logic to respond to innumerable theological problems. By doing so, they converted theology into an analytic discipline. Many theological treatises differed little from treatises on natural philosophy.

In his interesting chapter on “The Secret Arts of Alchemy and Astrology” (Chapter 8, 121–134), Hannam describes what was involved in astrology and the Church’s attitude toward it. But he ignores the opponents of astrology, of whom the greatest was Nicole Oresme (ca. 1320–1382). This is unfortunate because had he included Oresme’s hostile attitude toward astrology, he might have been led to Oresme’s greatest argument against it, namely that the celestial motions are probably incommensurable and therefore astrological predictions are based on inaccurate and imprecise information. Oresme demonstrates this by powerful probability arguments. Had Hannam pursued this theme, he would not have identified Jerome Cardan as the one who first developed and used probability arguments.

In his Treatise on the Commensurability or Incommensurability of the Celestial Motions, Oresme denounces astrological predictions. He declares:

it would be very repugnant that men should come to know about future events beforehand. It seems arrogant of them to believe that they can acquire a foreknowledge of future contingents, only some of which are subject to celestial powers.

It seems better, therefore, to assume the incommensurability of the celestial motions, since these difficulties do not follow from that [supposition]. Indeed, incommensurability is shown in yet another way, for as demonstrated elsewhere, when any two unknown magnitudes have been designated, it is more probable that they are incommensurable than commensurable, just as it is more probable that any unknown [number] proposed from a multitude of numbers would be non-perfect rather than perfect. Consequently, with regard to any two motions whose ratio is unknown to us, it is more probable that that ratio is irrational than rational—provided that no other consideration intervenes that was not taken into account in what has already been discussed.2

Indeed, not only did Oresme arrive at probability theory some two centuries before Cardan, but the latter, in his Opus novum de proportionibus (New Work on Ratios) includes six propositions that were very likely derived from Oresme’s Treatise on the Commensurability or Incommensurability of the Celestial Motions. The six propositions (propositions 47–52 of 233 in Cardano’s treatise) were devoted “to mobiles moving on circles, especially emphasizing their times and places of conjunction.”3 It should be emphasized that Oresme’s achievements in probability theory are, to this day, virtually unrecognized, whereas Cardan’s name will frequently turn up. But there can be no doubt about Oresme’s great contribution. Although Hannam may have been unaware of this important aspect of Oresme’s significant contributions, he does include Oresme’s achievements in establishing the mean speed theorem and his important discussions of the earth’s possible axial rotation.

Although natural philosophy lies at the heart of what we would call “medieval science,” Hannam says little about the nature of natural philosophy in the Middle Ages (there is no index entry for “natural philosophy”). He preferred to emphasize the seven liberal arts.

The objective Hannam set for himself is expressed in his book’s subtitle: “How the Medieval World Laid the Foundations of Modern Science.” Did he achieve his goal? I am convinced that he did. In the Conclusion, which is titled “A Scientific Revolution?”, Hannam, as mentioned earlier, identifies four cornerstones that together served to lay the foundations of modern science, namely, institutional, technological, metaphysical, and theoretical. The medieval university was the fundamental institutional entity. Under technology, Hannam mentions spectacles, magnetism, and the mechanical clock and observes that other technological advances increased agricultural productivity and raised living standards. By “metaphysics,” Hannam seems to mean natural philosophy, although why he calls it metaphysics is puzzling. Hannam rightly emphasizes that medieval natural philosophers sought to understand the natural workings of nature because the latter was God’s creation. He is right, but he should have gone further and emphasized that, within a university intellectual atmosphere, medieval natural philosophers developed a spirit of inquiry based on reason that led them to “probe and poke around,” often by pursuing counterfactual questions. It is this “probing and poking around” that led to many of the theories mentioned in Hannam’s fourth, and final, cornerstone, which were, as he says (p. 341), “derived from the way they combined mathematics with natural philosophy.” Hannam shows that Galileo appears to have made some of his great scientific contributions from ideas he derived directly or indirectly from medieval sources. But I would argue that even if Galileo and other seventeenth century natural philosophers were ignorant of all important medieval scientific ideas, they were undoubtedly influenced by medieval natural philosophy, even if unaware of it. Why? Because, although medieval natural philosophy was wholly transformed in the early modern period, seventeenth century scholars, such as Galileo, Kepler, and many others, were the beneficiaries of the medieval scholastic “spirit of free inquiry, the emphasis on reason, the variety of approaches to nature, and the core of problems to be studied.” (Grant 1996: 202) These vital characteristics were developed in the medieval universities, where for some four centuries—1200–1600—natural philosophy was the major subject of study. Without the highly developed natural philosophy of the medieval universities, with the characteristic features I have described, the great scientific achievements of the seventeenth century—or the Scientific Revolution, as it is usually called—could not have occurred. In sum, I wholly agree with Hannam’s assessment of medieval scholastic contributions to the scientific achievements of the early modern world.

Despite my few disagreements, Hannam has written a splendid book and fully supported his claim that the Middle Ages laid the foundations of modern science. He has admirably met another of his goals, namely that of acquainting a large non-academic audience about the way science and various aspects of natural philosophy functioned in medieval society and laid the foundation for modern science. Readers will also learn much about medicine, magic, alchemy, astrology, and especially technology. And they will learn about these important matters in the history of science against the broad background of the life and times of medieval and early modern societies. Although it was intended for a non-academic audience, this book would prove quite useful as a text in a university course in the history of science.


The quotations from Albert and Thomas are taken from Grant (2007: 252–253).


See Nicole Oresme and the Kinematics of Circular Motion: Tractatus de commensurabilitate vel incommensurabilitate motuum celi, edited with an Introduction, English Translation, and Commentary by Edward Grant (Madison: The University of Wisconsin Press, 1971), 321. The words “for as demonstrated elsewhere” refer to Oresme’s On Ratios of Ratios (Tractatus de proportionibus proportionum), Chapter Three, Proposition X in Nicole Oresme, De proportionibus proportionum and Ad pauca respicientes, edited with Introductions, English Translations, and Critical Notes by Edward Grant (Madison: The University of Wisconsin Press, 1966), 247–255.


See Nicole Oresme “De proportionibus proportionum”, 142–143.


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