The Christian Origins of Modern Science


There has been no great conflict between science and religion: on the contrary, Christianity was an essential factor in the rise of modern science.

Modern science stands as one of the great achievements of Western civilisation. And despite what you have heard, it is an achievement of the West, not of Islam, China or even ancient Greece. Historians of science are still reluctant to admit this. I think this is because they have always suffered from an inferiority complex in relation to their colleagues in the history faculty. This has meant that the fad of post-modernism bit them hard and refused to let go. Historians have developed a habit of praising Arabic and ancient Greek science as successful in their own terms but have lost sight of the fact that, objectively, they were quite false.

I have boundless respect for the early Greek and Islamic philosophers who struggled to comprehend the world. But most of what they taught, through no fault of their own, was woefully inaccurate. To take just one example, pre-modern medicine was an unmitigated disaster, far more likely to kill its patients than cure them. Luckily for us, today we can be much more confident that doctors really can cure us of many diseases. So the history of science should really be the story of how we went from being fundamentally wrong about the natural world to being, in large part, right. In fact, science as we know it today, with laboratories, experiments and a professional culture, is a recent phenomenon that did not appear until the nineteenth century. We usually look for its origin in the period of the 'scientific revolution' but Galileo and Newton did not appear in a vacuum. To understand why modern science arose in the West, we have to travel right the way back to the Middle Ages.

First of all, though, we need to dispose of a couple myths about scientific progress. A popular misconception is 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's true that certain religious doctrines contradict some scientific discoveries. The creation/evolution controversy is a case in point, but such quarrels have been surprisingly unusual. Even the infamous trial of Galileo, the other example of conflict most often cited, was a rare 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 rise of modern science 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. 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 marshalled in favour of the conflict thesis turns out to be bogus. The Church never tried to ban zero or human dissection; no one was burnt at the stake for scientific work; and no educated person in the Middle Ages thought that the world was flat, whatever the Bible might imply. Stories about popes excommunicating comets or banning lightning conductors on churches turn out to be fiction. Zealous Victorian historians did find occasional examples of ecclesiastical stupidity; but mostly the evidence was lacking, so they simply made it up.

In medieval Europe, things were different. Aristotle's faulty method was struck down by the Catholic Church, which allowed previously forbidden ideas to flourish.

Another 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.

Aristotle's 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. His scientific method led to madness.

There was one towering exception to this rule. Both the Greeks and Arabs excelled in mathematics. This was because pure rationalism works a treat when it is restricted to geometry. The imams had plenty of uses for maths as well: the Moslem 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 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.

In medieval Europe, things were different. Aristotle's faulty method was struck down by the Catholic Church, which allowed previously forbidden ideas to flourish. The Church also made natural philosophy a compulsory part of the course that it required theologians to follow. So, unlike in Islam, science had a central place in Christian centres of learning. And surprisingly, Christianity itself provided a worldview which was especially compatible with experimental science.

In 1085, the great Islamic city of Toledo in Spain fell to Alfonso IV, King of Castile. Christian forces captured the magnificent library intact and word soon spread about the fabulous riches contained therein. Europeans were well aware that they had lost much of the learning of the ancient world after the fall of Rome and they were keen to reacquire it. The resulting movement to translate Arabic and Greek scholarship into Latin meant that by 1200, Christians were back up to speed in science and mathematics. Initially, some churchmen were suspicious about all this new knowledge and feared that it would be misused to challenge the faith. When a nest of heretics was found in Paris and its environs, the resulting panic led to a temporary ban on Aristotle's natural philosophy. Scholars were furious and demanded that the forbidden books were reinstated. So, after a decent interval, the Pope rescinded the ban and Aristotle took his place at the heart of Christian education.

This gave Christians good reason to believe that science was a practical venture; that nature did follow fixed laws that could be discovered. It was also a theologically righteous path to pursue.

As we have seen, the danger of Aristotle was in his method. It was bad enough that several of his conclusions contradicted revealed theology. But, the problem went deeper than that. Because he had tried to deduce results deductively, Aristotle made them seem logically necessary. His admirers did not just claim that he was right, they said he had to be right. God himself was bound by what Aristotle thought because, despite his omnipotence, medieval theologians were agreed that even the Deity could not defy logic. But Aristotle was wrong about most of his natural philosophy. Science could go nowhere until the dead hand of the Greek sage was lifted from it.

The Church had to deal with this, even though it was primarily interested in theology and not science. The bishop of Paris, with papal approval, issued a list of opinions, drawn from the work of Aristotle and his medieval followers, which he declared heretical. The effect was paradoxically liberating. All of a sudden, European philosophers were freed to think outside the Aristotelian box. No longer could they assume that the Greeks were always right. Vacuums were no longer impossible. There could even be more than one universe. Now they could speculate on all sorts of things previously ruled out of court. The result was that the fourteenth century became a scientific golden age when much of the groundwork was laid for ideas that later ended up in the books of Copernicus and Galileo.

The Church still had to be convinced that natural philosophy could be bulwark and not an obstacle to theology. The job of persuasion was carried out by the Dominican friar Thomas Aquinas. In his massive work Summa theologica, Thomas carefully explained how faith and reason could be reconciled. He provided rational arguments for the existence of God and used logic to defend the Christian faith. Thomas's efforts meant that philosophy was made safe in the eyes of the Church and it cemented its position as a compulsory part of the course that doctors of divinity had to follow. As the new universities churned out graduates, there was a massive increase in the number of people who had knowledge of science and mathematics. And because the universities had to teach natural philosophy, they also provided a home to many professionals who could devote their careers to it.

Given today's perceptions of a conflict between science and religion, it is surprising to find that Christianity proved to be uniquely accommodating to the study of nature. While there is little in the Bible that could be called science, the book of Genesis is very clear about where the universe came from. Contrary to Aristotle's view that it is eternal, the Bible says that the world was created by God at the beginning of time. Christians believed that the world was created ex nihilo, out of nothing. God did not have to work from pre-existing material that resisted his purposes. This meant, as Genesis affirmed, that the creation turned out 'good' and as God wished it to be. Christian theologians held that He had also allowed the world to develop freely through natural laws which He had ordained. The order of nature followed these laws rather than God personally having to manipulate each atom. This is in contrast to a Muslim doctrine, often called occasionalism, which held that Allah was the sole source of cause and effect. There was no need for natural laws, only the direct will of Allah.

Another feature of the Christian God was his reliability. He was not capricious like the Olympians of ancient Greece or entirely beyond human comprehension, like Allah. This meant that natural philosophers knew that they could depend on the laws that He had laid down. Nature itself should reflect her creator by obeying His commandments. This gave Christians good reason to believe that science was a practical venture; that nature did follow fixed laws that could be discovered. It was also a theologically righteous path to pursue. Nonetheless, because God was free to do as he pleased, it was impossible to work out the laws of nature from rational analysis alone. The only way to discover His plan was to go out and look.

It was within this Christian milieu and the continuing tradition of medieval natural philosophy that Copernicus, Kepler and Galileo worked. But their discoveries were just one important chapter in the history of western science, the only science which has consistently produced true theories of nature.




James Hannam. "The Christian Origins of Modern Science." from God's Philosophers: How the Medieval World Laid the Foundations of Modern Science (London: Icon Books, 2009).

This article is reprinted with permission of the author, James Hannam.


James Hannam has a physics degree from the University of Oxford and a PhD in the History and Philosophy of Science from the University of Cambridge. He writes on the pre-modern and early modern history of science and religion. His first book God's Philosophers: How the Medieval World Laid the Foundations of Modern Science was published by Icon in 2009 (appearing in the US as The Genesis of Science: How the Christian Middle Ages Launched the Scientific Revolution) and his articles have appeared in several publications including the Spectator, the Mail on Sunday, History Today and First Things. He has also contributed to various academic journals. Dr Hannam is a member of the Science and Religion Forum and the British Society for the History of Science.

Copyright © 2012 James Hannam

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