The outlook of Christians was fundamentally different from that of the ancient Greeks. According to Christians, God revealed himself through the Bible and the Church. As Tertullian explained, scientific research became superfluous once the gospel of Jesus Christ was available. The Church taught that it knew all there was to be known. Christian knowledge was comprehensive and unquestionable. Rational investigation was therefore unnecessary. Existing learning was not merely superfluous, but positively harmful. Theologians were convinced that God had defined strict limits on the knowledge that human beings might acquire. As St. Augustine of Hippo put it "Hell was made for the inquisitive". To seek to discover more was a sin and therefore also a crime, the crime of curiositas* .

Christianity brought the Dark Ages to Europe, a period when scientific endeavour was abandoned and learning of all kinds was rooted out and destroyed. With the exception of military technology, the Church was to oppose advances in virtually every scientific discipline for many hundreds of years. Philosophers were persecuted and their books burned. Such was the persecution that men of learning were driven to destroy their own libraries rather than risk a volume being seen by a Christian informer. Efforts were made to destroy evidence of Greek successes. We can never know how much was lost forever. Some Greek learning was preserved because Christian heretics, notably Nestorians, took it east with them when they fled the wrath of the orthodox Church. These refugees flourished under Zoroastrian and Muslim rulers in centres like Damascus, Cairo, Baghdad and Gondeshapur in Persia. There they translated surviving works into Syriac, Hebrew and Arabic.

It was later re-translations of these works, mainly from Arabic into Latin, that fuelled humanism and the development of the scientific method in western Europe almost a millennium after Christian orthodoxy had begun its intellectual holocaust. Conquests of Constantinople by crusaders in 1204 and then by the Turks in 1453 both resulted in the flight of Greek scholars to western Europe. They brought remnants of more ancient works that had been preserved in the East. These influxes encouraged the revival of Greek learning, leading to an intellectual rebirth that we know as the European Renaissance.

Having produced no distinctive philosophy of its own, the early Church had adopted the philosophical ideas of Plato. For centuries Plato was honoured as a sort of quasi-Christian. Among the works brought back from the East were the writings of his pupil Aristotle. Aristotle appealed to medieval Christians even more than Plato, but some of his ideas seemed incompatible with theirs. Thomas Aquinas attempted to reconcile Aristotelian thought with Christianity, and for a while it was accepted that he had succeeded. Aristotle was now credited with almost divine authority, and it became as difficult to overturn his ideas as it was biblical ones. Time after time the Church would seek to suppress scientific discoveries by reference either to the Bible or to Aristotle.

Ignatius Loyola summed up the traditional Christian view when he said “We sacrifice the intellect to God” and Martin Luther was even more direct in expressing the view that “Reason is the Devil's harlot”. At the end of the seventeenth century churchmen — even Anglican churchmen — were still claiming that the Christian religion was the only real source of knowledge * , and the Bible was still regarded an infallible and comprehensive encyclopædia. It provided information on the origins, history and nature of the Universe, Earth, animals and mankind. How such ideas came to be abandoned by most Christians is the history of Western science. We will now look at a few examples of what happened when new scientific truths contradicted old religious ones, beginning with the most famous case of all.

Cosmology

…I humbly begged His Holiness to agree to give him the opportunity to justify himself. Then His Holiness answered that in these matters of the Holy Office the procedure was simply to arrive at a censure and then call the defendant to recant.
Letter from Francesco Niccolini to Andrea Cioli, about Galileo, dated 5th September 1632

For religious reasons it was necessary for Christian scholars to place Earth at the centre of all creation. God had created the Universe for humans, so it was natural that he should build it around them. Accepted Church doctrine in early times was that our world was flat and circular, and sat immobile at the centre of the cosmos *. The vault of the sky was a solid structure, a huge dome rather like a gigantic planetarium. Stars were physically moved around its inner surface by angels. Anyone adventurous and blasphemous enough could conceivably break through the firmament at the edge of the world into the hidden heavenly realms beyond.

Within the dome theologians imagined a number of concentric hemispheres separating a series of holy regions — the seven heavens that appear in Jewish, Christian and Muslim literature *. Churchmen knew exactly where the centre of their circumscribed world was. It was Jerusalem, as medieval maps confirm. Indeed the precise spot within Jerusalem could be identified, for it was where Jesus had been crucified. It is supposedly located in the Church of the Holy Sepulchre. The site of the crucifixion thus marked the radial centre of the hemispherical firmament — the exact centre of the Universe.

According to later theologians the heavens were fully spherical and rotated about a stationary spherical Earth suspended in space. These heavens were made of transparent crystal, which explained why they could not be seen. The Earth lay at divine rest at the centre of all creation, just as God did in his heaven This second spherical theory was certainly an advance on what had been believed before, but it was still well behind the ancient Greeks, who had known that Earth is spherical almost 2,000 years earlier. Parmenides of Elea recognised it to be so in the fifth century BC. Pythagoreans found proof that Earth was round: they noted that our planet cast a curved shadow on the surface of the Moon during lunar eclipses. Other Greeks spoke of the opposite side of the world where the Sun shone while it was their night. Eratosthenes of Alexandria (275-194 BC) calculated Earth's size and arrived at a circumference of 252,000 stades, which is thought to correspond to 39,690 km (24,663 miles) — only a little short of the correct figure for the polar circumference, which is 40,008 km (24,860 miles). Eratosthenes also developed the system of latitude and longitude. That Earth was spherical was so well established by Roman times that emperors carried an orb to signify their sovereignty over the whole world.

In the sixth century BC, Thales of Miletus learned from the Babylonians how to predict the motion of heavenly bodies. He was able to anticipate a solar eclipse in 585 BC. Anaxagoras of Clazomenœ, who was born around 500 BC, held the Sun to be an incandescent mass of hot stone — as near to the truth as he could have got. He also said that the Moon shone merely because of the Sun's reflected light, as indeed it does. Pythagoras seems to have speculated in the sixth century BC that Earth went round the Sun, not the Sun round Earth. Aristotle mentions Pythagoreans who regarded Earth as a planet — a heavenly body circling around the Sun, the central fire that created night and day. Towards the middle of the third century BC, Aristarchus of Samos further developed the Pythagorean theory that Earth was in motion about the Sun. Other philosophers wondered why, if the Pythagorean theory were right, the fixed stars did not appear to change position as Earth moved. But Aristarchus had an explanation for this. He pointed out that it could be accounted for by the vast distances to the fixed stars, a theory that was to be vindicated in the nineteenth century.

The ancient Pythagorean view was revived by Nicolaus Copernicus early in the sixteenth century, over 2,000 years after it had first been put forward. Copernicus did not dare to publish his ideas on the matter, because the Church was certain that Earth lay at the centre of everything. He kept his book, De Revolutionibus Orbium Cœlestium, secret for 36 years. It was published only after his death. The Inquisition would later condemn his cosmology as "that false Pythagorean doctrine utterly contrary to the Holy Scriptures". Their scriptural prooftext included Ecclesiastes 1:5, which talks about the Sun rising and setting, and Psalm 104:5 which says that Earth can never be moved. The Church knew beyond all doubt that the Sun rotated about Earth because on one occasion God had made it stand still in the sky (Joshua 10:12-13). According to the greatest Church authorities it was not possible to believe in the Pythagorean/Copernican system and still remain a Christian. Even Martin Luther agreed that this cosmology was incompatible with Christian faith.

The Church taught that sin and imperfection existed only at the centre of the Universe — on Earth and as far above its surface as the Moon. God's abode, the heavens, beyond the lunar orbit, were perfect. On Earth were imperfection and decay, and natural motion was in a straight line; in Heaven was perfection and constancy, and natural motion was perfectly circular. All celestial orbits were thus circular, and in particular the Sun moved around Earth in a circle. Apart from being wrong about which body revolves around which, the Church was also mistaken about the shape of celestial orbits. If heavenly bodies revolved around Earth in circular orbits then they would have constant apparent brightnesses. But the apparent brightnesses of planets vary, an observation that had led ancient Greeks to deduce, correctly, that the distances between Earth and various other planets were not constant. In fact, Earth and the other planets all orbit the Sun, and their orbits do not have the shapes of circles but rather ellipses, albeit ellipses that (for Earth and most of the other planets) closely resemble circles. In an impressive piece of mathematics, the German astronomer Johannes Kepler calculated the laws of motion for the elliptical orbits of the planets around the Sun. His book The New Astronomy effectively proved Copernicus" heliocentric theory. It was placed on the Index in 1609.

Another error of the Church was its denial that Earth spins on its own axis. Heraclides of Pontus had realised in the fourth century BC that Earth rotates once every 24 hours. A little later Aristarchus of Samos (c.310-230) had advanced a complete Copernican hypothesis. He said that all planets including Earth orbit the Sun, and that Earth itself rotates on its axis. By the early 1600s, Copernicus and Kepler had vindicated Aristarchus, but the Roman Church could not accept that he had been right, much less that it had been wrong.

The greatest scientist of his day, Galileo Galilei, was fascinated by the evidence, and saw that the model proposed by Aristarchus and Copernicus was better than the one taught by the Church. Galileo was censured for teaching Copernican cosmology in 1616. Suddenly, the full implications of this cosmology were appreciated. Copernicus was posthumously declared a heretic and his cosmological treatise placed on the Index.

Galileo could no longer teach the theory, but with papal approval he continued to discuss it. His discussions did not favour the Church's theory, so he found himself in trouble again. In 1633 Pope Urban VIII had him arraigned on a charge of heresy. He was found guilty. His sentence contained the following statements:

…by order of His Holiness and Most Eminent and Most Reverend Lord Cardinals of this Supreme and Universal Inquisition, the Assessor Theologians assessed the two propositions of the Sun's stability and the earth's motion as follows:

That the Sun is the centre of the universe and motionless is a proposition which is philosophically absurd and false, and formally heretical, for being explicitly contrary to Holy Scripture;

That the earth is neither the centre of the universe nor motionless but moves even with diurnal rotation is philosophically equally absurd and false, and theologically at least erroneous in the Faith *.

Galileo recanted under threats of torture by the Inquisition. He was obliged to say that it was the Sun and not Earth that moved, and to abjure his heretical depravity in claiming otherwise. He may have been tortured — we would not know because victims of the Inquisition were obliged to take an oath not to divulge what had happened to them. In any case he would have before his mind the image of Giordano Bruno, another great thinker of the age. Bruno had also considered possibilities denied by the Church. He said that stars were really distant suns, and that there could be inhabited planets orbiting them. He rejected the idea of a solid firmament. He thought the Universe infinite and denied that Earth was at its centre *. In 1600 he had been publicly burned at the stake in Rome for his heresies.

Old and sick, and well aware of Bruno's fate, Galileo now knelt in penitence before the inquisitors. His writing on the subject, the Dialogue Concerning the Two Chief World Systems, was placed on the Index. He was sentenced to life imprisonment. In fact he spent the rest of his life under house arrest, a mercy almost certainly attributable to the fact that he was a personal friend of the reigning Pope.

Galileo's Copernican ideas had not been the first to create difficulties. He had made many scientific discoveries, a number of which had contradicted Church teachings. He had looked through his early telescope at the Moon and realised that it was not at all like the theologians said. It had mountains, just as the Greek philosopher Anaxagoras had said 2,000 years earlier (anyone with normal eyesight and an open mind can see their shadows), and these mountains were interspersed with plains. Few theologians would look through his telescope to confirm his findings, for they already knew for a fact that the Moon had a smooth polished surface. Those who did look said that the shadows they saw must be blemishes in the telescope lenses. They did not test this hypothesis by rotating the telescope, or by using another telescope. There was no point — again because they knew for a fact that the surface was smooth.

Galileo found other difficulties with Church orthodoxy. Following Aristotle, the Church taught that natural motion on Earth was always in a straight line, but Galileo showed that projectiles describe parabolic curves. Aristotle said that a heavy object will naturally fall to the ground faster than a light one. Galileo showed that all objects fall at identical rates under gravity (unless some other force, like air resistance, acts on them). Since the Church had adopted Aristotle's teaching as its own, it was wrong every time he was.

The Church also disputed the existence of the moons of Jupiter. With his telescope Galileo had seen four moons in 1610, but churchmen said they did not exist. They could not exist because all heavenly bodies rotated around Earth. The existence of sunspots was another inconvenience. These were first studied seriously from around 1610 by Galileo and a German Jesuit priest, Christoph Scheiner (among others). Scheiner had to publish his findings under a pseudonym, because of Church opposition. The familiar argument was that the Sun, being a heavenly creation of God, must be perfect. Therefore its face could not suffer any form of blemish. The existence of sunspots thus continued to be disputed by theologians long after their discovery, even though they could (and can) sometimes be clearly seen with the naked eye around sunset. Comets provided yet another difficulty. On the one hand they were recognised as destructible, which meant that they must exist within the imperfect region bounded by the Moon; on the other hand it was realised in the seventeenth century that they orbit the Sun — which meant that they must lie beyond the Moon's orbit. Once again theological cosmology contradicted scientific cosmology. Whether they existed within or without the lunar orbit, the Church deemed that comets must have a purpose, and that purpose could only be to act as divine portents. Theologians explained how angels created them as the need arose and dismantled them when they were no longer needed *.

There was more. When Galileo turned his telescope on Venus he noticed that it had phases like the Moon. These phases had been predicted by the heliocentric theory, and provided another problem for the Church. Yet another difficulty was that through his telescope Galileo could see thousands of stars that were too dim to be seen with the naked eye. The problem here was that the Church taught that the stars, like everything else, existed only for the benefit of mankind. To devout churchmen it did not make sense for God to place anything in the firmament unless it visibly shed light, or was of some other practical use to people on Earth.

For similar reasons the Church stayed in the age of astrology while people were pioneering modern astronomy. Theologians knew for certain that devils were given to molesting people at certain phases of the Moon *. Even popes used the services of astrologers. For example, Julius II chose the date of his coronation on astrological calculations, and Paul III chose the time of each consistory (meeting of the college of cardinals) on a similar basis *. Leo X founded a chair of astrology. Astrology might be useful, but astronomy was not, because the Church already knew everything to be known about the mechanics of the Universe from God's infallible handbook. Even the men who pioneered astronomy spent their time trying to reconcile Church teachings to the real world. The consequence was that great minds were held back by fruitless attempts to match theology and observation. Scholars tried to explain planetary orbits as epicycles (i.e. compound circular motions) for a long time, because circles would be less offensive to orthodox religious ideas. Galileo himself spent time trying to accommodate the biblical account of the Sun standing still. Kepler might have made further important discoveries if he had not been constrained by the belief that planets are guided by angels. So might later cosmologists if they had not required God to wind up their mechanical universe like a giant clockwork toy. Such ideas affected even Isaac Newton. By the 1680s, Newton had deduced the same results concerning planetary motion as Kepler had arrived at, using his new theory of gravitation. He still imagined God nudging the planets back into line from time to time, which invited a degree of teasing from Leibnitz who wondered why God failed to get it right first time. Despite this, Newton's theory marked a turning point. Even if it was conceded that supernatural forces were needed for occasional fine-tuning, theologians were horrified by the idea of forces that acted without physical contact. If gravity could explain basic planetary motions, then supernatural explanations might soon become superfluous altogether — those guiding angels would become redundant. Newton was criticised for presuming to intrude into forbidden territory. As Edmund Halley put it, Newton had penetrated the secret mansions of the gods. Churchmen had imagined that they held all the keys to God's heavenly mansions and did not like trespassers, especially trespassers like Newton who could open doors that remained closed to them.

Edmund Halley is best remembered for giving his surname to a famous comet. He realised that various comets recorded in history were in fact the same comet reappearing every 76 years. This undermined the idea that comets were divine portents. It also suggested that theologians had been wrong about angels constructing and dismantling them as the need arose. The Anglican Church did not like trespassers any more than the Roman Catholic Church did, especially if their religious views were less than orthodox. Halley's views were less than orthodox. He believed that the world would continue forever, an idea that contradicted the doctrine of the Second Coming of Christ. Halley was suspected of atheism, and because of this he failed to win the Savilian Chair of Astronomy at Oxford in 1691-2. Its gift lay with the Anglican Church. Halley's was a petty affair in comparison to Galileo's , but the principle was the same. Churches did not want to hear theories that contradicted their own, and they did not want other people to hear them either.

Galileo's Dialogue Concerning the Two Chief World Systems stayed on the Index until 1835, an annually increasing embarrassment for educated Roman Catholic believers. By that time the divine role had been reduced to nothing. The French mathematician Pierre-Simon Laplace had established that those oddities that Newton had identified in the planetary orbits did not after all require gods or angels to correct them. They were, he showed, self-correcting. When Napoleon asked him where God came into celestial mechanics, Laplace replied "I have no need for that hypothesis".

By now it was clear to many that the theologians and their infallible truths had been comprehensively wrong. There is no solid firmament. Earth is not at the centre of the Universe, and nor is it stationary. Neither the Sun nor the planets revolve around it. Celestial orbits are not circular, and neither in general is motion in Earth's gravitational field a straight line. The Moon is not a perfect silver disk, nor is the Sun a perfect gold one.

In educated circles people would soon be noting that all significant advances in astronomy had been made since the Church lost its grip on cosmology in the seventeenth century. Churchmen who tried to hold the traditional line would find themselves distanced ever further from educated opinion. Nevertheless, senior clergymen continued to believe that angels were responsible for planetary movement and other phenomena well into the nineteenth century *. Some Christians still do, but they are now a small minority. Mainstream Churches have generally accommodated themselves to scientific discoveries, although without ever admitting earlier errors explicitly. The Vatican reviewed Galileo's case during the 1980s. After a ten-year enquiry the Roman Church exonerated itself and justified its earlier actions, an outcome that met with a degree of surprise in the wider world*. Cardinal Ratzinger speaking at La Sapienza University in Rome (and quoting Paul Feyerabend) described the Church's position as “reasonable and just”. This explains why, after he became Pope Benedict XVI, professors and students alike complained about his planned visit to the University in 2008, causing him to call it off*.

Bruno's case has not yet been reconsidered, and most of the evidence has apparently now mysteriously disappeared while in the custody of the Vatican.

Mathematics and Physics

Hypatia was devoted to her magic, astrolabes, and instruments of music .... She beguiled many people through her satanic wiles.
Bishop John of Nikiu, 4 th century

One might imagine that pure mathematics could not pose too much of a threat to Christianity. Not so. Mathematics was tantamount to enquiring into God's mind, and such presumption could not be permitted. Churchmen declared geometry to be the work of the Devil, and accused mathematicians of being the authors of all heresies. Ancient thinkers like Pythagoras were regarded as having been dangerous magicians. Living mathematicians were regarded in much the same way. Hypatia, a famous woman mathematician and head of the library at Alexandria in the fifth century, was seen as a major threat by Christians. She is thought to have invented the astrolabe, an astronomical instrument, but Christians made no distinction between science and magic.

In those days there appeared in Alexandria a female philosopher, a pagan named Hypatia, and she was devoted at all times to magic, astrolabes and instruments of music, and she beguiled many people through Satanic wiles.*

In 415 she was seized by monks and other followers of Cyril, the local bishop. They stripped her and dragged her naked through the streets to a church. They cut off chunks of her flesh with sharp sea-shells until she was dead, and then burned what was left of her body. (read John's account here >). Pagans were horrified, Christians delighted. For them Cyril was a hero. They dubbed him Theophilus or “Lover of God”. He is now St Cyril.

Another great saint, St Augustine of Hippo, often referred to as the Father of the Inquisition, shared the opinion of his fellow saint and all right thinking Christians:

The good Christian should beware of mathematicians and all those who make empty prophecies. The danger already exists that mathematicians have made a covenant with the Devil to darken the spirit and confine man in the bonds of Hell*.

Because of such hostility, mathematics progressed only a little beyond that of Euclid for many centuries. Indeed, the end of the flowering of mathematics in the ancient world is usually dated from the murder of Hypatia. How little progress was made after her time is demonstrated by the continued use of Greek textbooks. Euclid's Elements was still in common use in Christian schools into the twentieth century. Astrolabes are still in use today.

The Church had its own use for mathematics. In the Middle Ages almost all mathematical effort was directed towards calculating the date of Easter, a matter that the Church believed to be of the utmost importance. Complicated tables concerning so-called golden numbers and the movements of imaginary moons, called ecclesiastical moons, are still included in the Book of Common Prayer for this purpose. Real mathematics was still a form of diabolical magic. When the concept of zero was introduced from the East it was seen not as what it is — the most important advance since ancient times but, in the words of William of Malmsbury, as "dangerous Mohammedan magic". Late medieval popes led an extended battle against the alien and heretical concept.

When religious reformers cleaned up Oxford University they destroyed mathematical manuscripts believing them to be conjuring books*. It was almost certainly at this time that the great collection of fourteenth century works of the school of astronomers based at Merton College disappeared. In Tudor times mathematics was still a form of black magic, and the terms conjure and calculate were used as synonyms. Astrologers, conjurors and mathematicians were regarded as being the same*. In 1614 a Dominican preacher, Tommaso Caccini, could lampoon Galileo and all mathematicians as magicians and enemies of the faith.

Even in the eighteenth century scientists had to be wary of offending churchmen. Newton's theory of fluxions, now generally called differential calculus, the gateway to modern higher mathematics, was thought to be a threat. Bishop Berkeley tried to refute Newton's ideas, seeing them as incompatible with Christianity. Berkeley could still complain about "heathen zeros". The only reason Newton did not come under greater attack was that he concealed his true beliefs about Christianity and made a point of stating that he hoped his work would be useful to Christian apologists. His greatest work, the Principia, was deliberately written in an abstract style so that only mathematicians would understand the implications of it.

Christians were also opposed to atomic theory, largely because the Greek philosophers who had first proposed it had been atheists. These philosophers had held that the world came into existence through the natural interaction of atoms, and that life had developed out of a primeval slime. Leucippus had first developed an atomic theory, and it had been espoused by Democritus, Epicurus of Samos and the Roman philosopher Lucretius. They held that there is no purpose to the Universe and that everything is composed of physically indivisible atoms, with empty space between them. How else, they asked, could a knife cut an apple? If the apple were solid matter such a thing would be impossible.

Atoms were indestructible and were in perpetual motion, cannoning off each other when they collided, or sometimes combining if they interlocked. There were an enormous number of them, differing in size, shape and heat, and governed by mechanical laws. When men like Thomas Hobbes started to resurrect atomic theories in the seventeenth century, Christians were alarmed by the revival of this ancient horror. They were convinced that godlessness was a necessary corollary of atomism*. Perhaps they were right. The overwhelming majority of physicists today are both atomists and atheists.

Biology

The religion that is afraid of science dishonours God and commits suicide.
Ralph Waldo Emerson, Journals

Animals were an ever-increasing source of embarrassment to Christians. For one thing it became difficult to believe that they had all fitted into Noah's ark. As more and more species were discovered it became more and more difficult to reconcile the facts. Where was all the fodder stored, and what had the carnivores eaten during the voyage? How were the tropical animals kept warm, and the Arctic ones cold? How did Noah collect them all, and how did they all get back home afterwards? Finally, why were so many animals not mentioned in the Bible, God's infallible and comprehensive encyclopaedia?

Another problem was the question of why animals suffered, since they had never sinned like Adam and Eve and incurred God's wrath. One answer to this was that, despite appearances, they did not suffer. They were mere soulless automatons, so it did not matter what was done to them. This view has survived in the Roman Church to this day. But if animals did not have souls, how could they live at all? The answer to this was that they had a sort of lesser soul, or spirit, or "vital force" much inferior to a man's and even to a woman's , but indivisible just like theirs*. It was this spirit that animated them, just as souls animated human beings. In the eighteenth century this theory came under suspicion when it was discovered that movement persisted in the hearts of animals after death. How was this movement possible without an animating spirit? Again, muscle tissue, even when removed from the body, would contract if pricked. But how could tissue move without an animating spirit? Thinking people started to suspect that life was not spiritual at all, but merely mechanical. Such people were called materialists and were branded by the Church as atheists.

The questions remained and indeed multiplied. If the human personality was the outward manifestation of the human soul, why was it affected by disease, or drugs, or food and drink? For that matter why was it affected by age, or temperature, or climate? Then in the 1740s Abraham Trembley discovered that a freshwater polyp, or hydra, could regenerate itself when cut into pieces. Did each piece have a spirit? If animal spirits were divisible after all, why not human souls? For the time being the question had to be left open, for inquisitive Christians had still not yet succeeded in identifying the seat of the soul. As soon as its physical location could be established, Christian truth could be proved once and for all and the materialists confounded. So far the search has been unsuccessful. The Churches seem to have given up hope of identifying a biological soul, and now deny that there is such a thing. Biologists long ago switched to more productive areas of research.

Earth Science

Had I been present at the Creation, I would have given some useful hints for the better ordering of the Universe. Attributed to Alfonso "the Wise", king of Castile (1221-1284)

Leonardo da Vinci had suggested that Earth's past could be explained by natural forces, but this suggestion was at odds with the Christian view. God had made the world, and neither it nor its inhabitants were mutable. Any theory that contradicted this view was not to be countenanced. In the seventeenth century the Bible was still the infallible source of all knowledge:

No one seeking to enquire into rocks or minerals, into Earth history or the formation of Earth's configuration could afford to ignore or deny the value of his primary source, the Bible*.

The immutability of Earth and its biology was to remain the established view up to the nineteenth century. One factor that constrained many pathways of thought was the chronology of Earth and the Universe. The Jews had held that the world had been created around 4000 BC (a belief that is still repeated at every Rosh Hashanah and every Jewish wedding ceremony). Because of an arithmetical error by a monk, it became accepted Church doctrine that it had actually been created in 4004 BC. In the sixteenth century Dr John Lightfoot, Vice-chancellor of Cambridge University had even worked out the date and time: God started his creation at 9 am on 23 rd October 4004 BC. Bishop Ussher's estimate in the mid-seventeenth century differed by 3 hours. He placed the time of creation at noon on the same day*. A detailed chronology was worked out for the whole of the Bible, with dates attributed to every event. Such chronologies were accorded respect comparable to the biblical text itself. When Thomas Paine pointed out the absurdities and contradictions in the Bible in The Age of Reason, he laid considerable stress on the absurdities of the received chronology. Both he and his readers believed that an attack on these chronologies was an attack on Christianity itself. Their common view was that if the biblical chronologies were wrong, then Christianity itself was discredited.

The position that accepted biblical chronology could not be wrong precluded any understanding of Earth sciences, or indeed any possibility of initiating such sciences. That geological processes took millions of years to shape Earth was unthinkable, as it was unthinkable that evolution had been responsible for the diversity of life on Earth. God did not make mistakes or change his mind about his creation. Animal life was immutable. Mankind had existed from the formation of Earth in 4004 BC, and so had the various animal species. The rose red city of Petra was not merely poetically half as old as time, but literally half as old as time. Climate and geography were the same as they had always been. God had created perfect animals, and allowed imperfect ones like snakes, frogs and mice, to be made by demons or to arise spontaneously from the process of putrefaction*.

Once again the Church was entirely mistaken, and ancient Greek thinkers had been on the right track. Anaximander, a Greek born over 600 years before Jesus, had had an inkling about evolution. He said that land animals had developed from aquatic ones and that mankind was descended from a different species. He reasoned that human beings have such long infancies that they could not always have survived as they do now. To Christians such ideas were blasphemous. God's creation was immutable. There was no possibility of change. Species could not evolve any more than they could die out. God had ordained their existence, and God did not make mistakes. All manner of explanations were found for the existence of fossils. The ones still popularly known as devil's toenails were believed to be demonic nail parings (they are actually the remains of bivalve molluscs of the genus Gryphaea). Belemnites were the remnants of God's thunderbolts. Ammonites were coiled snakes that had been turned to stone by an obliging local saint, such as St Hilda. The fact that they had no heads was conveniently rectified by carving heads on, so that they could be sold to pilgrims as proof of the saint's remarkable power. Fossils of ancient marine life found inland were explained by Noah's flood which had supposedly washed them there.

In the seventeenth century skeletal remains of mammoths were discovered in England. These remains were also attributed to the flood, but not everyone saw the explanation as wholly satisfactory. Another possibility was that they were the remains of elephants that had been brought over by the Romans, but this was not viable either, and neither was the theory that they were the bones of giants ("There were giants in the earth in those days.... " (Genesis 6:4)). Other discoveries contributed to the confusion. Fossils found in Germany in 1696 had to be dismissed as a "sport of nature", which was hardly a satisfactory explanation.

As early as the 1740s the Swedish taxonomist Linnaeus had realised that the 5,600 species he had named could not possibly have been accommodated by Noah's ark. In the second half of the century Robert Hooke theorised that species were mutable and liable to extinction*. He and others who took an interest in geology incurred the antagonism of churchmen for such ideas. The systematic cataloguing of fossils gave support to Hooke's views, for it became increasingly obvious that species had indeed become extinct. Christian teaching was also undermined by animal remains found in places with currently unsuitable climates.

In 1785 James Hutton "the father of modern geology" published his theory that the earth must be millions of years old. All of the Christian Churches were outraged and opposed him as they opposed all scientific theories that contradicted the bible. As Hutton's biographer put it *:

The extraordinary hold of the Bible prevented genuine freethinking about the history and working of the planet, and the few open-minded scientists who did emerge were quickly censured by the church.

Theologians had always claimed that their divine encyclopædia was not only infallible but also comprehensive. It contained all world knowledge. This belief was sustained for centuries in the face of unforeseen discoveries. It even survived the unexpected discovery of the Americas but was dealt a fatal blow by the discovery of Australasia. In the eighteenth century, Christians were at a loss to explain how the existence of a whole continent could have been omitted from their comprehensive encyclopædia. Particularly embarrassing was the fact that earlier Christians had executed men for affirming that there existed undiscovered habitable lands on the other side of the world. Persecutors had justified themselves by reference to the Bible's infallibility and comprehensiveness. Now it was clear that they had been wrong, and the heretics had been right. For a while, the devout searched for explanations, loopholes, anything to reconcile the contradictions. None was convincing, and ever more geological discoveries were being made. By the nineteenth century the Church's traditional teachings had become untenable, but geologists and other academics were still being deprived of their careers for mentioning it.

Chemistry

Do you really believe that the sciences would ever have originated and grown if the way had not been prepared by magicians, alchemists, astrologers and witches ...
Friedrich Wilhelm Nietzsche (1844-1900), The Gay Science

Once Aristotle had found favour with the Christian Church, his theory that earthly matter was composed of four elements — earth, air, water and fire — was adapted and clung to despite its flaws. Any real investigation into the chemical properties of matter was suppressed. Those who tried were branded as alchemists and risked the censure of the Church authorities, although the possibility of transmuting lead into gold seems to have been too much of an attraction for many churchmen. Some employed professional alchemists: others practised alchemy themselves.

Alchemists are sometimes dismissed as little more than conjurers, but the fact is that, until chemistry emerged as a science in the wake of the Enlightenment, it was alchemists who made whatever progress was made in the field of chemistry. Alchemists were familiar with elements such as sulphur, arsenic, antimony, mercury, gold, silver and other metals. They knew that arsenic was poisonous, despite the fact that it promotes growth and increases appetite. If conventional Christian physicians had known as much, quite a few people over the centuries might have enjoyed longer lives. Alchemists created compounds from elements, for example cinnabar (mercuric sulphide). They knew about acids such as vitriol (sulphuric acid), aqua fortis (nitric acid) and aqua regia (a mixture of nitric and hydrochloric acids). They used these acids, and other methods, to refine metals. They employed techniques such as distillation to produce aqua vitæ, alcohol distilled to a high proof. They used saltpetre (potassium nitrate) to make gunpowder. One of them, Böttger (c.1682-1719) discovered how to make porcelain. They developed scientific theories about chemical reactions. The specialist equipment they developed can still be identified in modern laboratories.

It was alchemists who originated the theory that combustion involved phlogiston. In this case they were wrong, but they had formulated a scientifically testable theory, and in testing it the element oxygen was discovered. The alchemist Theophrastus Bombastus von Hohenheim (1493-1541) alone arguably did more for medicine than all approved Church physicians put together over one and a half millennia. Aware of his own abilities he called himself Paracelsus because he believed himself to have surpassed Celsus, the early anti-Christian polymath. Paracelsus started the battle between scientific medicine and the atrophied Church version of Galenic medicine. The Church regarded him as an enemy, and the feeling was reciprocated (Paracelsus likened Luther and the Pope to two whores discussing chastity ). Iron and other elements , copper sulphate and potassium sulphate were added to pharmacopœia through Paracelsus , and he was the first to realise a connection between goitre and cretinism. He made advances on many fronts, learning from herbalists and wise-women. He rejected the idea of panaceas in favour of specific medical treatments.

Alchemy was proto-chemistry, and as such attracted the attention of distinguished scientists. Although Robert Boyle publicly discredited alchemy he believed in its fundamental objective, transmutation, and wrote at least two treatises on the subject. Newton suspected that Boyle's role in repealing a statute against alchemy had been inspired by his own transmutation experiments*. Newton was himself an advocate of alchemy, and was widely criticised for it. At every step alchemists and proto-chemists faced opposition from the Church and its physicians. Chemistry emerged as a separate scientific discipline only in the nineteenth century, just after the Church had lost its power to prohibit independent research.

Pharmacy and Medicine

And the prayer of faith shall save the sick.... James 5:14-15

Herbalists had existed since ancient times, and herbalism was known everywhere. The Mesopotamians, for example, knew about hellebore, hyoscyamus, mandrake and opium. Such knowledge was scorned by the Church, as were herbalists themselves. Like alchemists, they were often accused of practising witchcraft. Had churchmen taken a more positive interest they might have learned that witches" sabbats owed their existence more to hallucinogens such as hyoscine than to Satan. They might also have learned that naturally occurring compounds can be used as antibiotics and anaesthetics. Mandrake, hemp and poppy were all alkaloids traditionally used as anaesthetics. As well as hyoscine (scopolamine), modern drugs such as picrotoxin, serpasil and cocaine were all documented in ancient pharmacopœias.

Frazier's famous Golden Bough, mistletoe, also known as all-heal, was used for remedies throughout Europe. The Church shunned it because of its pagan connotations. Ivy too was used for medicinal purposes, being a diaphoretic and cathartic. Willow bark provided an early version of aspirin for fevers and headaches*. Again, herbalists had known for centuries that dried foxglove leaves could be used to treat heart conditions, but it was not until 1775 that a botanist, William Withering, having learned the use of foxgloves (Digitalis purpurea) for treating dropsy from an old woman, introduced digitalis into orthodox medicine.

For many centuries the Church clung to the theory of signatures. Theologians taught that God had created certain plants with magical medicinal properties and that he had left clues to these properties. Thus a yellow blossom would cure jaundice, and a red one could improve the blood. A root shaped like a foot would relieve gout. Like so many other beliefs of the Church, this one was utterly mistaken and served only to hold up progress. Objective research was pointless because the Church already knew the answers. Pharmacy therefore remained static, confined in a straitjacket of error.

The Church retarded and even regressed other areas of medicine, rejecting sophisticated rational ideas of ancient times. Ancient peoples had practised surgery, including cataract operations, brain surgery and plastic surgery. They used ligatures. They were aware of the importance of public health and personal hygiene. Followers of Hippocrates held that every illness has a natural cause. Christianity rejected all of this. In their view illness was indisputably caused by sin, diabolical possession, witchcraft and other satanic forces. To deny it was to invite the attentions of the Inquisition. Those who carried out medical research were therefore constantly at risk. Men such as Leonardo da Vinci were obliged to carry out research in secret. Any publicity was dangerous. The man who recognised mental illness as the explanation for diabolical possession was persecuted and obliged to flee for his life. Anyone who adopted Hippocratic techniques was regarded as a heretic. Medical assistance was an attempt to confound the will of God. A professor of medicine at Bologna who used skin grafts for plastic surgery was charged with impiety. Powerful churchmen forbade vaccination during smallpox epidemics because it was "against the natural law". Anaesthesia was prohibited on the grounds that if God meant us to suffer, then we ought to accept the suffering and not seek to ameliorate it. It was better that a woman with an ectopic pregnancy should die, in accordance with God's will, than that an operation should be performed. Christian morality informed official medicine. So it was that Christian physicians adopted the view that sexual activity was responsible for all manner of physical ills, a view that even minimal scientific research could have discredited centuries ago.

Philology

And Noah was five hundred years old: and Noah begat Shem, Ham, and Japheth. Genesis 5:32

The Church taught that human language was a gift from God, and the fact that there were many languages was explained by reference to the Bible — that infallible encyclopædia of all world knowledge. The story was that for a while after the flood all people spoke the same language (Genesis 11:1). When people attempted to build a tower reaching up to Heaven, God confounded their plan by making them speak different languages. The story of this tower, the so-called Tower of Babel, thus accounted for the world's different languages. No better explanation was possible until the Church lost its absolute control on the subject.

The first important steps in philology were taken by Johann Herder, a student of Immanuel Kant, in an essay published in 1772. For the first time the topic was approached rationally, and the origin and development of languages investigated. Still, it was always politic to mantle advances in biblical lore. A convenient and enduring story was that three important language groups were derived from Noah's three sons: Ham, Shem and Japheth. It had long been held that they had given rise to the populations of Africa, Asia and Europe respectively. With a little development this idea could be adopted to label the known family groups. Ham's descendants spoke Hamitic, a North African family of languages including Egyptian and Berber. Shem's descendants spoke Semitic, a Middle Eastern family including Hebrew and Arabic, and Japheth's spoke Japhetic, a group now usually known as the Indo-European family of languages. Relationships within the Indo-European family were identified and explained by William Jones in the eighteenth century.

The Greeks and Romans had been aware of similarities between various languages. Stoics and Alexandrian philosophers had theorised about the origins of language and developed the study of comparative linguistics. Without the coming of Christianity they might well have carried out important comparative studies, for example identifying the principal language groups, and perhaps making discoveries that are now impossible. Knowledge of languages such as Hittite, Etruscan, Gothic and Pictish is now lost, probably forever. As in so many areas of science, it is quite possible that the Greeks or Romans did carry out important work, and that it was destroyed by later Christians because it contradicted their own biblical explanation.

Philosophy

Philosophy for Philosophers, Religion for the rest Averroës (1126-1198)

Philosophy is another discipline that flourished in the ancient world. Christians did not like it, mainly because philosophers often arrived at conclusions inimical to the Christian faith. Some Greek and Roman philosophers saw the gods as human inventions and religion as an unnecessary evil. Diagoras of Melos, Lucian, Socrates, Anaxagoras and Seneca were all religious doubters. Leucippus held the belief (anathema to later Christians) that there were natural laws in the Universe. Democritus, anticipating the modern anthropologist's discovery of sky gods, suggested that religion was just a primitive personification of natural phenomena like thunder and lightning. Others noted that important beneficial things tended to be deified — things like fire and water, or the Sun and Moon. One surviving fragment of text suggests that the gods were a deliberate human intervention introduced to encourage good behaviour*. Epicurus of Samos (c.341-270 BC) saw good and evil as human conceptions and regarded religion as an unnecessary cause of fear. His primary motivation for studying nature was to rid the world of its superstition. Lucretius, a Roman philosopher, advocated morality without religion in his great poetic work De Rerum Natura. All of these ideas find echoes in modern thought.

Greek philosophers such as Xenophanes and Parmenides took the view that there was only one god. It was also clear to them that to be true, a religion must be equally available to all people. It was a commonplace in the fourth century BC that the gods were all one. Like modern Christian theologians, educated people in the Hellenic world interpreted their religion in terms of sophisticated myths and timeless psychological truths. Platonic philosophers thought about the nature of God and speculated that it might be the cosmos, masquerading under another name. The similarity with modern pantheistic ideas of God is striking. As Lucan wrote when Christianity was still an obscure Jewish sect:

Is the abode of God anywhere but in the earth, and sea, and sky, and air, and virtue? Why do we seek heavenly ones beyond? Whatever you see, and whatever you touch, that is Jupiter*.

Early Christians, lacking any philosopher of note, initially attached themselves to the Neo-Platonic school but contributed little - arguably nothing. Christians knew that there was only one path to truth, and that it was theirs. Philosophy was therefore at best mistaken and at worst positively evil. According to one Christian theory, philosophy was not even a human enterprise. It was the product of fallen angels, wickedly sharing the secrets of Heaven with the ungodly. So it was that philosophers were persecuted, and philosophy abandoned.

In the twelfth century Western Christendom rediscovered Aristotle. The problem was that he seemed to be right about so many things, yet some of them appeared to contradict known biblical truths. Plato was abandoned and attempts were made to reconcile Christianity with Aristotelian thought. These attempts appeared to have succeeded for a while in the thirteenth century when Thomas Aquinas synthesised Aristotelian reason and Christian faith. Philosophical investigations were now reduced to the sort of speculation popularly characterised by questions such as how many angels could dance on the point of a needle, and whether the damned shed real tears in Hell. This sort of speculation characterised a type of philosophy called scholasticism. It was as near as theologians ever came to anything like ancient or modern philosophy. Even at the time, it was recognised as absurd. Thomas More described scholastic theology as milking a billygoat into a sieve. It is no mere chance that a leading medieval Christian philosopher, Duns Scotus, a genuinely intelligent man, has had his name turned into the word dunce.

Aquinas's carefully constructed synthesis was soon being weakened by the facts, an inconvenient phenomenon since it was recognised that "truth cannot contradict truth". Within a generation his synthesis was fatally undermined by William of Occam, but a façade was propped up until its Aristotelian foundations were demolished by Galileo and Kepler and the whole edifice was consigned to history's rubble tip. The philosophical theories of the Roman Church thus became untenable, yet have never been formally abandoned*. Apart from the work of William of Occam, it is fair to say that virtually no significant advances were made during the many centuries that scholastic theology dominated philosophy under the Christian Church. In fact many philosophers would say that no substantial advance was made between the time of Aristotle and the eighteenth century. Any churchman who looked as though he might make a useful contribution was silenced. We have already seen what happened to William of Occam himself and to men like him: Pierre Abélard, Roger Bacon, Nicolaus Copernicus, Giordano Bruno and Michael Servetus.

Sir Francis Bacon (1561-1626) pioneered the scientific inductive method of inferring general laws from the observation of phenomena. Soon, men like Hobbes and Spinoza revived genuine philosophy outside the Church. In the coming centuries sceptics like Voltaire, Locke, Hume and J. S. Mill would turn it back into a genuine academic discipline. The Enlightenment would end the period of domination of philosophy by the Church's scholasticism. Once again, competing schools would flourish, as they had done 2,000 years earlier under the ancient Greeks.

The Church dominated philosophy for centuries and produced almost nothing that modern philosophers would recognise as useful or even meaningful. By contrast, the works of the ancient Greeks are still studied intensively and feature in university courses. So are the works of Spinoza, Locke and Hume. Their intellectual successors, Bertrand Russell and G. E. Moore, developed an analytical philosophy that encompassed contemporary work at Oxford, Cambridge and Vienna and is now the world's largest philosophical movement. The works of Voltaire and Hobbes are long-term best sellers. Scholasticism on the other hand is now barely recognised as philosophy at all, except by some theologians. Otherwise it is of interest only to historians.

Notes

§ It was a long time before America was known for certain to be a separate continent. In the meanwhile its existence could be considered consistent with the second book of Esdras, which was interpreted as saying that there was only one continent.

§ Augustine, De vera religione 3.4; 4.7; 29.52; 38.70-1; 49.94; 52.101-54.105. As a modern scholar explains: "The Christian attitude towards the concept of curiositas was largely determined in the Middle Ages by what Augustine had to say on the matter: he placed curiosity on the list of sinful qualities. His example was followed by Bernard of Clairvaux who coined the phrase turpis curiositas (scandalous curiosity), and Thomas Aquinas, who contrasted curiositas with studiositas so that curiositas (curiosity) gained a bad connotation and was associated with vanity, pride, scandal and suchlike." Jan Van Herwaarden, Between Saint James and Erasmus, Studies in Late-Medieval Religious Life: Devotion and Pilgrimage in the Netherlands (Brill, 2003), ISBN 90 04 12984 7, citing Bernard of Claivaux, Sermones in Cantica XXXVI, Migne PL 183, col 968-9 and Aquinas, Summa Theologiae II, ii 166-7

§ An interesting experiment is to take any objective source of information about great world developments in the arts and sciences arranged chronologically (there are many books and websites arranged like this) — discard those advances that originated outside traditional Christendom. What you are left with is a pattern of steady advance up until the Christian era, then a tiny trickle of advances through the 1300 years or so of Christian hegemony, then a gradual increase of new discoveries following the Renaissance followed by an explosion at the Enlightenment when the Church lost its grip on power. Now go back to that tiny trickle during the Christian period and take a look at how many of them were the work of “heretics”. Depending on the source you will probably arrive at a figure between 95% and 100%.

§. Hipparchus estimated the distance to the Moon (which onaverage is about 385,000 km or 240,000 miles) to within 5 per cent of the correct figure. Ptolemy estimated the average distance of the Moon from Earth at 29.5 times Earth's diameter. The correct figure is about 30.2.

§. Even senior academics thought that religion was the only source of knowledge. One notable one was the Master of Christ's College, Cambridge, Ralph Cudworth, The True Intellectual System of the Universe (1678).

§. Revelation 7:1 clearly refers to Earth's four corners. It is not obvious how there could be four corners if Earth was circular and flat, but orthodoxy nevertheless held that there were.

§. See for example 2 Corinthians 12:2, andmore explicitly the Koran 41:10-13 and 67:4-6.

§. Inquisitors" sentence dated 22 nd June 1633, quoted by Finocchiaro, The Galileo Affair, p 288. [I have taken the liberty of changing the word world to universe, as this better conveys the intended meaning, without going into detail about Finocchiaro's usage of the word world — which is of course in any case a translation into English — JM].

§. Giordano Bruno, On the Infinite Universe and Worlds ( London, 1584).

§. Kramer and Sprenger, Malleus Maleficarum, Pt I, q5.

§. Seznec, The Survival of Pagan Gods, p 57.

§. "The angels are the real cause of movement, light, life and the elementary principles which are offered to our senses in different combinations, and thus suggest the idea of cause and effect and what we call the laws of nature". Cardinal Newman, Apologia pro Vita Sua, 1864, p 152.

§. The Times, 10 th May 1983. See also "Inquisition in the Clear over Galileo", The Independent on Sunday, 11 th November 1992.

§. John Paul II was loudly heckled when he spoke at La Sapienza University in 1991, but Cardinal Ratzinger was even less liked. For the 2008 cancellation See Galileo protest halts pope's visit. http://www.cnn.com/2008/WORLD/europe/01/15/pope.protest/index.html and Papal visit scuppered by scholars http://news.bbc.co.uk/2/hi/europe/7188860.stm.

§. The quotation is from John, Bishop of Nikiu, from his Chronicle 84.87-103. For a full translation of his account of Hypatia's murder, read John's account here >

§. St Augustine, De Genesi ad Litteram, II, xvii, 37. This English translation is from Morris. Kline, Mathematics in Western Culture. Oxford University Press, (New York,: 1953). The original Latin reads: Quapropter bono christiano, sive mathematici, sive quilibet impie divinantium, maxime dicentes vera, cavendi sunt, ne consortio daemoniorum animam deceptam, pacto quodam societatis irretiant. Christians at this time made no distinction between mathematicians, astronomers and astrologers all of whom they believed to be inspired by demons.

§. John Aubrey, Brief Lives, p 29, cited by Peter J. Zetterberg, "The Mistaking of “The Mathematics” for Magic in Tudor and Stuart England", Sixteenth Century Journal, v11 (1980), p 85.

§. John Aubrey, Brief Lives, p 167.

§. Redwood, Reason, Ridicule and Religion, pp 109-110 and 216.

§. Alternatively, all living things had spirits, but humans had souls in addition to their spirits (cf. 1 Thessalonians 5:23).

§. Redwood, Reason, Ridicule and Religion, p 116.

§. For a sympathetic assessment of Ussher's chronology see Stephen J Gould, Eight Little Piggies, Jonathan Cape (London, 1993), Chapter 12 ("Fall in the House of Ussher"). The French, following the Jesuit Petavius, placed the creation on Monday 26 th October, 21 years later than Ussher.

§. Kramerand Sprenger, Malleus Maleficarum, Pt II, q1, c8.

§. Robert Hooke, The Posthumous Works ( London, 1705).

§. Jack Repcheck, The Man Who Found Time: James Hutton and the Discovery of the Earth's Antiquity, Perseus Publishing, Cambridge, MA, 2003, p. 101

§. H. W. Turnbull (ed.), The Correspondence of Isaac Newton ( Cambridge, 1941), iii, p 217.

§. Willow bark and other barks and plants provided salicylic acid, the structure and properties of which are almost identical to those of aspirin (acetylsalicylic acid).

§. Critas, Sysyphus, fragment 25.

§. Lucan (AD 39-65) Pharsalia, I, 128.

§. For example the Church theory of "Universals" proved to be a dead end, and the distinction between "substance" and "accidents" a positive embarrassment, which the Roman Church is still stuck with because the concept of Transubstantiation depends upon it.