Carl Sagan and the Myth of the Medieval Gap

| By and (guest author) on Reading the Book of Nature

ABOVE: In September 1980, a thirteen-part TV series called “Cosmos: A Personal Voyage” debuted on PBS stations across the United States. Written by the late Carl Sagan, his soon-to-be wife Ann Druyan, and his former student Steven Soter, it brought Sagan and his sonorous voice worldwide fame. The companion book has also been hugely popular, selling more than five million copies. By drawing attention to the Myth of the Medieval Gap and other fantasies, Sagan probably did more (unintentionally) to advance historical fiction than anyone since Andrew Dickson White. (image of the first edition from Amazon)

Introduction by Ted Davis

Stephen Snobelen’s series on science, religion, and the New Atheism continues today, as he examines some of the ways in which religious skeptics and others have endorsed the false idea that science suffered severely under domination by the Catholic Church during the Middle Ages. Dr. Snobelen calls this “the Myth of the Medieval Gap.” His essay continues after the next heading.

The Myth of the Medieval Gap (by Stephen Snobelen)

If there is a fundamental conflict between science and religion—especially between science and Christianity—then a period during which Christianity was the dominant cultural force should be characterised by a stagnation, decline or even absence of science. As we saw in a previous column, there is no essential conflict between science and religion; instead, there is some harmony, some dialogue, some independence and some conflict. Some of this is localised conflict and some is constructed for rhetorical and political purposes.

However, another implicit essentialism accompanies this belief—namely, that something called “science” already existed prior to the beginning of Christianity and re-emerged only after Christianity’s influence began to abate. For those who hold the Conflict Thesis, it is axiomatic that science existed in Ancient Greece, only to languish and retreat during the Middle Ages. This is the Myth of the Medieval Gap, in which ideology is applied to history. Although there is a hefty dose of a priori thinking in all of this, the myth also rests in part on a common intuition that the Middle Ages were characterised by ignorance and backwardness. Of course, the term ‘Medieval’ is often used as a pejorative to describe ignorance and backwardness—and as a way for us to bask in our own enlightened state. It’s no accident that Andrew Dickson White actually used that word in exactly this way. The widespread belief that this period was characterised by ignorance helps explain why so many simply take it for granted that Medieval people believed in a flat Earth. Yet this idea is also a myth, even though Neil deGrasse Tyson tweeted it (and was quickly corrected by his followers), Commander Riker and Captain Picard mentioned it in Star Trek: The Next Generation, and former President Barack Obama alluded to it in a speech about climate change. So, too, is the common belief that the Catholic Church prohibited human dissection in this period, despite the efforts of Harvard historian Katharine Park to debunk it.

What do the specialist historians say about science during the Middle Ages? First, it is only with significant qualifications that we can say science existed in Ancient Greece. To say that there is something identifiable as “science” and people identifiable as “scientists” in Ancient Greece is to think in ahistorical rational reconstructionist terms (I’ll return to this in a future column). Second, insofar as we can speak of Greek science, it was already in decline before Christianity came to political power. Third, while it is true that the first half of the Middle Ages did not enjoy the intellectual vibrancy of the second half, this can be explained in large part by various pivotal historical contingencies, not the least of which were the highly disruptive Barbarian invasions. Nevertheless, in most historical periods the second half usually enjoys more advances, including those in science and technology. This is true of the Early Modern Period, the nineteenth century, the twentieth century and (if we survive) will likely be true of the twenty-first as well. Fourth, there was a great deal of innovation in science and technology in the second half of the Middle Ages on the part of Christian and Muslim philosophers—so much so, in fact, that by the end of the Medieval period, science and technology had reached a state of sophistication and refinement that far surpassed that of the Greeks. Not bad for a bunch of Medievals.

The innovations and inventions of the Middle Ages are too diverse and numerous to list here; a few will have to suffice. Universities emerged starting in the eleventh century and their curricula included subjects we would now include in the sciences, including geometry and astronomy. Nothing as grand as Gothic architecture (which began in the twelfth century) could be accomplished in the Ancient Greco-Roman world. The Voyages of Discovery began in the Middle Ages, starting with the Irish and the Vikings. Medieval Europe gave us the horse collar, the rudder, eye glasses, buttons, trousers, the fork, windmills and the mechanical escapement clock. The printing press was a late Medieval invention. Medieval Europeans also benefited from innovations from outside Europe that the Greeks and Romans did not possess, including paper, gunpowder, the compass and the Hindu-Arabic numeral system. (See Chiara Frugoni, Inventions of the Middle Ages; Frances and Joseph Gies, Cathedral, Forge and Waterwheel; and Jeffrey R. Wigelsworth, Science and Technology in Medieval European Life.) Islamic civilisation brought innovations in mathematics, astronomy, optics and other fields to Europe that the Greeks were centuries too early to experience. Yes, these were from outside Christianity, but it demonstrates that the history of science has a good deal of contingency and that any idea that something like modern science would have continued to develop among the Greeks is far too simplistic. The Myth of the Medieval Gap also shunts aside substantial innovations in the practice and theory of science, including the contributions of Robert Grosseteste (a Catholic bishop) and Roger Bacon (a Franciscan) to the empirical method, William of Ockham’s “Razor” (the parsimony principle), and the impetus theory of Jean Buridan. Another important fact usually left out by proponents of the Medieval Gap is the invention of the Cyrillic script (the basis of several alphabets) during the so-called “Dark Ages” by Christian missionaries, thus setting these cultures on the road to literacy.

Those who argue that Christian Europe suppressed science fail to ask just how Christian Europe actually was at various points in the Middle Ages. In fact, Europe wasn’t fully Christianised until the early modern period, when part of northern Scandinavia became Lutheran. Large parts of Europe, especially in the north, remained pagan. The Iberian peninsula became a Muslim territory in the eighth century, and parts remained thus until the fall of Grenada in 1492. Those who promote the idea that the Middle Ages was a scientific backwater make much of the apparent correlation between the spread of Christianity and the relative lack of scientific and technological innovation at the beginning of that period, which lasted roughly 1000 years. What they fail to realize is the impact of Barbarian Invasions and political dislocations.

But, if we play the correlation-equals-causation game (which is a fallacy to begin with), then this argument proves more than advocates of the Medieval Gap want. For instance, there is a common assumption that Europe in the Middle Ages and the Early Modern Period was a cultural monolith dominated by the Church. This can hardly be said of the first half of the Middle Ages. Yet, it was only when the Catholic Church had consolidated its power in the second half of the period that there was a relative flourishing of science and technology. More spectacularly, it was precisely the period when Europe was at its most Christian—the sixteenth and seventeenth centuries—that science as we now know it emerged. (I am not saying that Christianity was in any simple way responsible for the emergence of modern science, only that the correlation argument can come back to bite its proponents).

In sum, the Myth of the Medieval Gap has a surface plausibility, not only because the first half of the Middle Ages was relatively bereft of scientific innovation—giving this myth, like many other myths, some basis in reality—but also because it exaggerates the achievements of Greek Science and downplays the achievements  of the Middle Ages, especially in the area of technology. Much of its traction comes without much intellectual effort, because it rests on the pre-existing, essentialistic (but culturally widespread) notion that science and religion are necessarily in conflict with each other. Yes, one can find some examples of hostility towards some aspects of Greek learning in the early history of the Church; Tertullian would be a prime example. However, the hostility was mostly directed against Greek philosophy generally, not against what we would call science today.  At the same time, one can also find many examples of Christian clergy who held a generally positive attitude towards Greek philosophy, such as Clement of Alexandria. Even in figures like Augustine, we find deep respect for astronomy—something much closer to modern science than many other parts of Greek philosophy. Sound and well-documented rebuttals of the Medieval Gap are available and easily accessible (see the references below). It is thus surprising that the myth is still actively promoted by some very well educated people.

Carl Sagan as Myth-Maker

Carl Sagan’s justly celebrated 1980 television series Cosmos is one of the most successful and popular science documentaries ever produced. Its thirteen episodes provide a tour of both science and the universe, and Sagan’s enthusiasm for science and discovery is palpable throughout. I use this series in a course I teach on science and the media as an example of a science documentary done right. This is not to say that it is without defects. A religious viewer will likely find Sagan’s more overt criticisms of religion (especially Christianity) grating, even while atheist viewers would likely applaud. But these elements are more subjective. There are other elements where Sagan unquestionably gets his history wrong. Perhaps the most egregious example is the infamous white space in his timeline of science and technology from the companion book to the series: see the image at right. Here, Sagan places some of the heroes of Greek science: Thales, Pythagoras, Plato, Ptolemy. This is followed by a note beside the early 400s that reads: “Destruction of Alexandrian Library, death of Hypatia, onset of ‘Dark Ages’.” Then comes a large white space that is finally interrupted with the names Columbus, Leonardo and Copernicus clustered around the year 1500. A telling note at the bottom of the timeline reads: “The millennium gap in the middle of the diagram represents a poignant lost opportunity for the human species.” The intended meaning is clear, even though the cluster of names around and immediately after the years 1500 are those of Christians (including Kepler, Huygens and Newton).

RIGHT: This diagram, from p. 335 in the 1982 edition of Carl Sagan’s Cosmos, depicts his historically impoverished understanding of the Middle Ages. Photograph by Stephen Snobelen.

In his book and television series, Sagan portrays the Alexandrian philosopher Hypatia as a martyr of science who died at the hands of fanatical, anti-intellectualist Christians. The implication is that the violent death of this woman is a potent symbol of the anti-scientific ethos of Christianity. Yet, as a neo-Platonist, Hypatia was much more of a religious mystic and even a proto-monotheist than a proto-atheist or atheist—as she is incorrectly insinuated to be in the 2009 film, Agora. (For incisive commentary on the many major inaccuracies in this film by atheist blogger Tim O’Neill, see this and this.) The Library of Alexandria formed part of the Museum of Alexandria. It was founded as a temple to the Muses, was headed by a priest, and functioned as a religious shrine as well as a centre of learning (Lindberg, The Beginnings of Western Science, p. 72 ). Sagan’s book implies that the library was destroyed by Christians after the death of Hypatia, but the original library (the Great Library) was in fact long since gone by this time—first devastated by a fire caused by Julius Caesar’s troops in 48 BC and thereafter through a gradual decline. Even the daughter library was likely no more at this point, since it had been housed in the Serapeum, which was destroyed in 391, and there is no evidence that the Serapeum held the library at this late date. And, Hypatia’s death had more to do with politics than religion.

Sagan’s Cosmos reinforced both the Medieval Gap and the anti-Christian account of Hypatia’s death in popular culture. But this is myth-making, not history. The only real gap here is in Sagan’s knowledge of the history of science.

Looking Ahead

Snobelen continues his study of this myth next time, when he considers similar unfounded claims by (among others) major New Atheist authors like Jerry Coyne, A. C. Grayling, and David Mills. Come join us again for more enlightening analysis of modern mythology.




Davis, Ted. "Carl Sagan and the Myth of the Medieval Gap " N.p., 9 Feb. 2017. Web. 19 August 2017.


Davis, T. (2017, February 9). Carl Sagan and the Myth of the Medieval Gap
Retrieved August 19, 2017, from

References & Credits

References and Suggestions for Further Reading

An earlier version of this essay was published as Stephen D. Snobelen, “Science, religion and the New Atheism,” in The New Atheism, ed. Susan Harris (Charlottetown: St. Peter Publications, 2013), pp. 109-44.  BioLogos and the author are grateful to St. Peter Publications (the only source for purchasing this book) for permission to publish this updated version online.

For more background for this column, see the series by James Hannam, a Catholic historian of science whose book on medieval science was a finalist for a prize awarded by the Royal Society. Katherine Park has thoroughly debunked the myth that the Medieval Church prohibited human dissection; her chapter in Galileo Goes to Jail provides a brief, very accessible summary of her work. The World Was Never Flat, a video by theologian Joshua Moritz, neatly summarizes modern scholarship on that myth. For more refutations of the Myth of the Medieval Gap, see The Beginnings of Western Science (2007) by the late David C. Lindberg; the chapters by Lindberg and Michael H. Shank in Galileo Goes to Jail; and The Foundations of Modern Science in the Middle Ages (1996) by Edward Grant, a leading expert on medieval natural philosophy and its university context.

About the Authors

Dr. Snobelen's research and teaching interests include history of science (early modern and nineteenth century), science and religion, science in popular culture, the popularization of science, radical theology in the early modern period, and millenarianism. His primary research efforts are currently devoted to interpreting Isaac Newton’s theological manuscripts and understanding the relationships between Newton’s science and his religion.

Dr. Snobelen has consulted for and appeared in television documentaries on Isaac Newton, including Newton: The Dark Heretic. His most popular course is on science fiction film, which he uses to introduce historical, philosophical, and ethical themes about science and technology to undergraduates in the humanities, sciences, and engineering. He and his wife Julia have four children who help keep them grounded in the more important things of life.


More posts by Stephen Snobelen

Ted Davis

Ted Davis is Fellow of the History of Science for the BioLogos Foundation and Professor of the History of Science at Messiah College. A former high school science teacher, Ted studied history and philosophy of science at Indiana University, where his mentor was the late Richard S. Westfall, author of the definitive biography of Isaac Newton. With the English historian Michael Hunter, Ted edited The Works of Robert Boyle, 14 vols. (London: Pickering & Chatto, 1999-2000), but his interests include the whole 2000-year interaction of Christianity and science. Author of dozens of scholarly articles and essays, Ted is one of few historians who have written extensively about both the Scientific Revolution and modern America. He and his wife Kathy enjoy theater, music, and traveling to new places.

More posts by Ted Davis