Medieval Christianity and the Rise of Modern Science, Part 1

| By James Hannam


Medieval Christianity and the Rise of Modern Science, Part 1

Today's entry was written by James Hannam. Please note the views expressed here are those of the author, not necessarily of BioLogos. You can read more about what we believe here.

Readers of the Biologus Forum do not need to be told that the alleged conflict between science and religion is a myth. The conflict thesis was born in the salons of ancien régime France where philosophes like Voltaire and Jean le Rond d’Alembert used it as a weapon against the Catholic Church. It was further developed in Victorian England by T.H. Huxley in his battle to diminish the influence of the clergy in London’s Royal Society. And it was perfected in American universities by the likes of Andrew Dickson White, first president of Cornell University, who provided the theory with intellectual ballast in his heavily annotated A History of the Warfare of Science with Theology (1896). Today, historians of science have long disposed of the conflict thesis, but it lives on in the popular imagination.

The inevitable companion to the idea that the Church has held back scientific progress is that we must look outside Christendom to discover the origin of modern science. But this is also false. Modern science stands as one of the great achievements of Western civilization. And, despite what we have often heard, it is certainly an achievement of the West, not of Islam, China or even ancient Greece. Many historians of science are still reluctant to admit this. This may be because the fad of post-modernism bit them hard and has refused to let go. They have developed a habit of praising Arabic and ancient Greek science as successful on their own terms but they have lost sight of the fact that, viewed objectively, the theories advanced by early science were quite false.

Of course, we should have respect the Greek and Islamic natural philosophers who struggled to comprehend the world. But most of what they taught, through no fault of their own, was woefully inaccurate. This was because their aims for science were nothing like ours. They wanted to understand nature in terms that made sense of their ethical or religious beliefs, and formed their theories accordingly.

To take just one example, pre-modern medicine was an unmitigated disaster, far more likely to kill patients than cure them. Treatments such as bleeding and purging could only weaken the constitution of the sick, reducing their bodies’ capacity to fight off infection. It is no surprise to find that the most celebrated doctor of antiquity, Galen of Pergamum (left), considered himself as much a philosopher as a healer. Given the ineffectiveness of learned physicians, it’s little wonder that people put so much stock in miracles and magic. Perhaps the most surprising thing is that doctors were able to maintain their professional status through all the centuries that they could do little more that hasten their clients to the grave. Luckily for us, we can be much more confident that modern medicine really can cure us of many diseases. So the history of science should be the story of how we went from being fundamentally wrong about the natural world to being, in large part, right.

Science as we imagine it today, with laboratories, experiments and a professional culture, is a recent phenomenon that did not appear until the nineteenth century. But its origins can be found much earlier and we usually look for them in the period known as the ‘scientific revolution’. It is commonly believed that the recovery of Greek philosophy during the Renaissance gave Western civilization the inspiration it needed to launch this revolutionary way of looking at the world. In this view, hardly anything of consequence for science occurred between the fall of Rome and the era of Copernicus and Galileo. Carl Sagan produced a timeline of scientific progress in his book Cosmos (1980) showing nothing at all happening between AD415 and AD1543. But this is an illusion foisted on us by the samementalité that declared science and religion must be in conflict. The truth is that to understand why modern science arose uniquely in the West, we have to travel all the way back to the Middle Ages.

Dispelling Myths

Before we do that, we should finally dispose of the two myths about scientific progress that we noted above. Firstly, as we have seen, the popular view remains that religion has held back science at every opportunity. Many people still believe that science has advanced by fighting superstition and making the world safe for rational enquiry. It is true that certain religious doctrines contradict some scientific discoveries. The creation/evolution controversy is a case in point, but such quarrels have been surprisingly rare. Even the infamous trial of Galileo, the other example of conflict most often cited, was an aberration in the Catholic Church’s usual supportive attitude towards science.

On the other hand, the problems with the thesis that science and faith are locked in a historical conflict are formidable. For a start, the so-called ‘scientific revolution’ in the seventeenth century coincided with the period when Christian belief in Europe was at its strongest. Only after science had triumphed did religion start to suffer any sort of decline. And, if Christianity really had tried to hold back scientific progress, the chances are that it would have succeeded. Modern science would not have arisen in Christian Europe at all.

As it happens, much of the evidence marshaled in favor of the conflict thesis turns out to be bogus. The Church never tried to outlaw zero or human dissection; no one was burnt at the stake for scientific ideas (not even Giordano Bruno); and no educated person in the Middle Ages thought that the world was flat, whatever the Bible might imply. Popes have had better things to do than banning vaccination or lightning conductors on churches. The thought of a pope excommunicating Halley’s Comet is absurd, but this has not prevented the tale of Calixtus III (right) doing just that from entering scientific folklore. It is remarkable that authors today, who consider themselves skeptics, can swallow some of these stories whole. Carl Sagan introduced his readers to a ‘baloney detector’ in his book, The Demon-Haunted World (1997). It is a great shame he never used it on his own writings. He presented a completely fictitious account of the murder of the pagan philosopher Hypatia in Cosmos and falsely blamed Christians for the destruction of the Alexandrian library.

Zealous Victorian historians did find occasional examples of ecclesiastical stupidity, such as the Boston pastor who warned that lightning strikes caused earthquakes. They rewrote history to make these marginal figures into leaders of opinion. Religious dissidents who paid the ultimate price for their faith were recast as champions of reason. Pope Boniface VIII issued a bull intended to stop crusaders sending their bones home for burial; he would have been most surprised to hear that, according to Andrew Dickson White, he had legislated against human dissection. Whenever a priest questioned a scientific theory, which they often did in their capacity as amateur scientists, this was held up as an example of religious obstruction. Historians have been debunking these legends for over a century now, but they continue to be recycled by each new generation.

The role of ancient Greek and Islamic thought

The other myth about the rise of science is that westerners only had to pick up the baton from the ancient Greeks, or, as has been more recently alleged, the Islamic caliphate. In reality, modern science is qualitatively different from the natural philosophy practiced by the likes of Aristotle or Avicenna. Aristotle started from the passive observation of nature and then built up a system based on rational argument. This had two enormous disadvantages: compared to controlled experiments, passive observation is usually misleading; and not even Aristotle’s powers of reason could prevent blunders in his arguments.

His discussion of motion is a case in point. He observed that everyday objects tend to stop when nothing was pushing them. From this observation, he deduced the principle that all moving objects must be moved by something else. He elevated this principle to the status of a logical certainty and then used it to explain other kinds of motion. He even thought that it successfully proved the existence of God. If the universe as a whole is full of movement, he argued, it requires an exterior unmoved mover,—that is, God—to keep it going. But of course, Aristotle’s initial observation was just a specific instance without any general applicability. We now know that objects do not stop when there is no force on them. They tend to keep going in a straight line: a principle enshrined as Newton’s First Law. Other observations led Aristotle to decree it certain that a vacuum can never exist; that heavy objects fall faster than light ones and that the earth must occupy the centre of the universe. All wrong. Aristotle, alas, was mistaken about almost everything. This was not because he was a fool but because he was practicing a natural philosophy that could never lead to true theories.


Islamic science suffered from similar drawbacks. Advances made by Muslim natural philosophers were significant, but rather more modest than we are usually led to believe. The importance of Alhazen’s investigations into the properties of light is indubitable. They were used by Roger Bacon in his own writings on perspectiva and thence were integrated into the modern theory of vision developed by Johannes Kepler. Even so, Alhazen’s experimental method was limited and not carried forward by his immediate successors. Similarly, the intuition of Ibn al-Nafis, in the thirteenth century, concerning the circulation of blood between the heart and the lungs is deeply impressive. But there is no evidence that he had any impact on the rediscovery of this phenomenon by Michael Servetus and Realdo Columbo three centuries later.

Consequently, we should be skeptical about some of the claims made for Islamic science in some recent television shows and books, not to mention in Wikipedia. That said, the misattribution of scientific advances to Islamic sources has sometimes been the fault of the pioneers who actually discovered them. Alchemy is a case in point. During the Middle Ages, it was customary for Christian alchemists to write their treatises under the name of the fabled Arab savant Geber. It is not surprising that later historians mistakenly assigned developments such as the first production of powerful acids as well as the isolation of alcohol to Geber himself. Alcohol was even assigned an Arabic name by Christian authors. We now know that he probably did not write any of the works attributed to him.

On the other hand, there was one towering exception to the rule that early science tended to be bunk: both the Greeks and Arabs excelled in mathematics. This was because pure rationalism works a treat when it is restricted to geometry and arithmetic. The imams had plenty of practical uses for math, as well: the Muslim calendar follows the moon and not the solar year, while mosques had to be orientated towards Mecca. Both these religious problems required mathematical solutions. It’s also said that the complicated rules of Islamic inheritance made algebra indispensable. Even our word algebra is a corruption of al-jabr, the name of an Arabic textbook widely used by Christians.

Despite these genuine contributions, it is nevertheless fair to say that neither Aristotelian rationality nor Islamic mathematics was the key to the developments that made the modern world possible. As we shall see in the second part of this essay tomorrow, the very different cultural situation in medieval Europe allowed for Aristotle’s faulty method to be criticised by the Catholic Church, meaning that previously forbidden ideas could flourish. The Church also made natural philosophy a compulsory part of the course that it required trainee theologians to follow. So, unlike in Islamic madrassas, science had a central place in Christian centers of learning. Indeed, it was a Christian worldview that proved especially compatible with—even necessary for—the rise of modern science.


About the Author

James Hannam

James Hannam took a Physics degree at Oxford before training as an accountant. He enjoyed a successful career in the City, mainly financing film production, but harboured ambitions to write about the history of science. In 2001, he started a part time MA at Birkbeck College, London in Historical Research. In 2003, he began his PhD program at Cambridge in the History and Philosophy of Science, and wrote his thesis on the decline of medieval learning during the 16th century. His book for general readers, God's Philosophers: How the Medieval World Laid the Foundation of Modern Science, was published by Icon in 2009. It is titled in the U.S. as The Genesis of Science: How the Christian Middle Ages Launched the Scientific Revolution. The book was shortlisted for the Royal Society Prize for Science Books in 2010. James lives in Kent, England with his wife and two children.