CHAPTER 5
Heresy and Reason

On 20 November 1210, in the marketplace of Champeaux near Paris, ten members of a small sect called the Amalricians were burned at the stake. As the heretics were led out to their deaths, a storm was brewing. The cloaks of the clergy flapped in the wind and then pouring rain soaked the straw that was to act as tinder on the pyre. After tying the victims to the uprights, the king’s executioner more than earned his pay as he got a roaring fire going in the damp conditions. The Amalricians had reason to be grateful for the weather; when wet wood burns it generates a great deal more smoke than usual and they would have suffocated before the flames even reached them. Among the people who gathered to watch, some muttered that the storm demonstrated that the souls of the heretics were damned and surely destined for hell. On this occasion, the crowd were treated to a particularly gruesome spectacle. Next to the ten live victims, the executioner threw onto the pyre the rotten remains of another individual who had died three years previously. This was the corpse of an academic, Amaury of Bène (who died around 1207), who had taught at the university of Paris. The condemned men, who included a teacher and two students from the university, were his disciples.¹

Amaury had enjoyed a long career at the university of Paris, studying philosophy before joining the theology faculty. There, he ran into trouble by espousing beliefs that no orthodox Christian could ever accept. Although it is hard to know for certain what these beliefs were, Amaury was apparently a pantheist who believed that God and the universe were one and the same. He also claimed that there was no life after death and that the material world was all that existed. Today, these beliefs would be unexceptional but in the early thirteenth century they constituted scandalous blasphemy. That didn’t stop them being attractive, however, and Amaury gained a following both among members of the university and the outside world. It was not the Church who first ordered Amaury to recant, but his colleagues in the theology faculty. Rather than give in to these demands, he travelled to Rome and appealed to Pope Innocent III. The Pope listened and then backed the Paris theologians. Now Amaury had no choice but to deny his previous beliefs. He returned chastised to Paris and died shortly thereafter.² However, not all of his followers were willing to renounce their alleged errors and a small sect developed around Paris teaching pantheism and materialism. It was all very well to discuss heretical ideas in the rarefied atmosphere of the university, but once they leaked out beyond the faculty walls trouble was inevitable.

Among the Amalricians, as they became known, was a goldsmith by the name of William of Arria. He claimed to be a prophet and spread the word to whoever would listen. One day in early 1210, he started to proselytise a certain Master Ralph, who listened politely but with mounting concern once he realised that William’s doctrines were heretical. When William had departed, Ralph sought out the bishop of Paris. At the time, the bishop’s most pressing concern was the building of the enormous new cathedral of Notre Dame. After 40 years of work, the nave, choir and transept already dominated the centre of Paris and rapid progress was being made on the western front. Heresy, however, demanded the bishop’s immediate attention. The prelate ordered Ralph to join the Amalricians undercover and report back all he heard after three months. He did as he was commanded, and travelled around the countryside with the group as they spread their new religion among the peasant folk. When they returned to Paris, he told the bishop about their activities. Fourteen of the ringleaders were quickly rounded up for questioning.³

At first, the Church authorities used a softly-softly approach to try to coax the Amalricians back into the fold. Initially this method was successful and several of the prisoners confessed their errors. However, it appears that they subsequently backtracked and refused to renounce the heresy. They believed that Amaury had spoken the truth and that the Catholic Church itself was mistaken. Faced with such obduracy, the Church authorities gave up the fight and handed ten of the Amalricians over to the secular authorities. That could only mean one thing – they would suffer the ghastly fate of heretics under the severe civil law rather than the gentler ecclesiastical alternatives. The king’s executioner burnt ten of the sectarians and four others, who had probably recanted at the last minute, were confined to a monastery for the rest of their lives.⁴

The University of Paris Bans Aristotle

The sad story of the Amalricians was to have long-lasting consequences for natural philosophy. The bishop of Paris was shocked to find a nest of heretics so close to home and set out to find the root of the problem. It seemed to him that the worst fears of St Bernard of Clairvaux had been realised. Amaury had used reason and logic not to defend Christianity, but to undermine it. The bishop formed a local synod of his colleagues who issued the formal excommunication of Amaury and his followers. The decree went on to ban the books assumed to have inspired the heresy. ‘Neither the works of Aristotle on natural philosophy’, it read, ‘nor their commentaries are to be read at Paris in public or private. This we forbid under penalty of excommunication.’⁵ Aristotle, the bishops thought, was the original source of many of Amaury’s ideas. It is no use wondering what exactly the synod found objectionable in the books that they banned because, almost certainly, they had not read them. There is nothing like a moral panic to give rise to bad law.

Nevertheless, there is no doubt that Aristotle’s natural philosophy contradicted Christianity on some central points. Christians believe that we all have souls that survive death; that God created the world at a definite point in the past; and, most fundamentally, that God is all-powerful and not subject to the laws of nature himself. Aristotle disagreed with all of this. He insisted the world was eternal, that it had existed forever and always would exist. There was no moment of creation and no creator. He was also highly ambivalent about personal immortality. Although he believed that humans have a soul, he also held that it dissolves at death. There is no last judgement, heaven or hell. This was bad enough, but Aristotle hardly believed in God either. The idea of a personal God, who answered prayers and intervened in the lives of men, was complete nonsense as far as the Greek philosopher was concerned. He did believe in a ‘prime mover’ who kept the universe turning, but this impersonal being had no interest in mankind and was nothing like the God of the Bible.

The Church could deal with these problems quite easily by officially stating that Aristotle was wrong where he contradicted a specific Christian doctrine. However, there was another issue that ran like a vein all the way through his natural philosophy and metaphysics. This was the question of necessity, which was of critical importance to the development of science.

Both Aristotle and Christian thinkers accepted that there are fixed natural laws, but the Greek philosopher went further. For Aristotle, the iron shackles of logical necessity determined what the laws of nature had to be.⁶ They were not just the ones upon which God had deliberately decided, they were the only ones he could have used. Even if God had actually created the world, he would have had no choice about how it turned out.⁷ It was as if he had to follow a pre-existing recipe and, unless he followed it precisely, the result would be a mess. There was no divine freedom and the Creator was not really responsible for the way of the world. That is not to say that Aristotle thought that the world was without purpose. But for him, the purposes of nature were not the same as the divine plan of God.

Obviously, this was dangerous stuff and once it became clear that it had influenced Amaury, the bishop of Paris’s synod promptly banned it. Scholars at the university of Paris continued to study diligently the rest of Aristotle’s works, such as his logic and ethics, so they probably flouted the ban as well. Besides, it only applied to Paris. At the other universities, such as Oxford and Cambridge, the synod’s writ had no authority. In 1229, advertisements for a new university at Toulouse made much of the fact that students there could freely read those of Aristotle’s works that were prohibited at Paris. The Pope reacted to this impudent attempt to poach students from Paris by extending the ban to Toulouse as well.⁸

The professors at Paris, which was, after all, the biggest and most prestigious university in Europe, were furious that the bishop was presuming to tell them what they could and could not read. Almost everyone agreed that the synod had overreacted in banning Aristotle’s natural philosophy outright. However, getting a synod to admit they had made a mistake was not an easy thing to do. The only person who could overturn the decision was the Pope, and he would not want to seem soft on heresy. The solution was simply to wait a while until the fuss had died down and then try to get the ban rescinded.

By 1230, Notre Dame de Paris’s western facade was complete, together with the rose window that still dominates the nave. The famous pair of towers that would complete the structure was rising over the city. The cathedral represented the church’s renewed self-confidence, and this was reflected in the decision to revisit the question of the ban on Aristotle. In 1231, the university suggested to Pope Gregory IX that the original synod may have gone overboard in banning all the natural philosophy books. His Holiness agreed and sent two letters to Paris. The first pardoned everyone who had ignored the initial ban. The second read:

We have learned that the books on nature prohibited in Paris by the provincial council are said to contain both useful and useless matter. Lest the useful be tainted by the useless, we command that … examining the books as is convenient, subtly and with prudence, you entirely excise what you find there to be erroneous or likely to give scandal or offence. Thus, with the suspect material removed, the rest may be studied without delay and without fault.⁹

We do not know if a committee was ever formed to expunge Aristotle’s books because, as it turned out, no one bothered to remove anything. Reading all of the previously banned books on nature quickly became a central component of the course of study. The university of Paris syllabus from 1255 included all of Aristotle’s books in the curriculum for students taking their bachelor’s or master’s degrees.¹⁰

If Aristotle was so dangerous, why did the authorities make reading him a compulsory element of courses at all European universities, even going so far as to take the highly unusual step of reversing a ban? The answer is that, as the Pope said, Aristotle was incredibly useful. Ironically he was, when properly understood, one of the most formidable weapons against exactly what the Church feared most – heresy.

Heresy and the Inquisition

During the Middle Ages, heresy was an increasing problem. Especially prevalent in the south of France, the Rhineland and northern Italy, it was not as if heretics had only recently appeared. They had existed throughout the previous 800 years but the Church had hardly bothered them. When heretics did not represent a serious threat to the growing power of the papacy, the Church could safely ignore heterodox belief. Only high-profile cases like Peter Abelard’s attracted papal attention, and then only because his prestige as a theologian was so great. In the twelfth century, this relaxed attitude changed.

One important feature of Christianity at this time was the increased level of lay piety and the pressure for ecclesiastical reform.¹¹ This heightened religious feeling of lay people, perhaps increased further by the start of the crusades in 1095, meant that extremism became more common. Pope Urban II (1042–99) had preached the first crusade from his pulpit with the intention of recapturing the Holy Land from its Muslim rulers. Not everyone wanted to travel all the way to the Middle East, however, and mobs began to look for infidels closer to home. One notorious aspect of this was that Jews became the targets of violence. Canon law allowed Jews to practise their religion and stated that they could not be subject to violence or be forced to have their children baptised.¹² But to the mob, these edicts were iniquitous and the Jews fair targets. A series of pogroms by domestic crusaders along the Rhine killed thousands in 1096 despite the efforts of the local bishops to protect the victims. The mobs were not above attacking the clergy from whom the Jews had sought sanctuary. The archbishop of Mainz had to flee for his life for this reason.¹³

Heretics in the midst of the faithful were believed to be a further manifestation of the enemy within. The common people feared that they would be damned themselves if they allowed deviants to live peaceably among them. This is why Master Ralph had so quickly reported his encounter with the Amalricians to the bishop of Paris. And if the authorities were insufficiently zealous in dealing with the heretics, then the mob would do it for them. At Cologne in 1144, the crowd seized two leaders of a heretical sect even while the archbishop of Cologne was interrogating them. Without any thought for due process, the mob dragged their prey outside and burnt them there and then.¹⁴

The Church also grew more concerned about heretics because they were growing more common. The largest heretical sect was the Cathars. They seem to have originated in eastern Europe and may have been a descendant of an early offshoot of Christianity called Manichaeism. Both the Cathars and the Manichaeans believed that there were two gods, one good and one evil. There was disagreement over whether the two gods were equally powerful, but the evil one created and ruled the material world. This meant that matter itself was evil and mankind should try to escape it by concentrating wholly on the spiritual.¹⁵ The most committed Cathars, called the perfecti, were strict ascetics who abstained from eating meat and having sex. They hoped that by their refusal to countenance material things they might be able to free themselves from the shackles of the flesh. They were strongest in southern France around Toulouse, where they enjoyed considerable influence and the protection of the nobility.

With heretics growing in numbers and the common people taking matters into their own hands, something had to be done. While it accepted that unrepentant heretics deserved death, the Church was perturbed about not giving them a chance to return to the faith. It was clear that dealing with heresy required a new system. For this reason, a series of dynamic popes developed a legal process called inquisition.¹⁶

During the Middle Ages, there was no single monolithic institution that we can call ‘The Inquisition’. Inquisitors were simply individual agents of the Pope who travelled to areas afflicted by heresy and used their special powers to deal with it. They worked in conjunction with the local secular and ecclesiastical authorities. Several papal bulls granted the inquisitors their powers, culminating in two from Pope Gregory IX that were issued in the same year that he lifted the ban on Aristotle. Authorising the activities of two inquisitors, he wrote:

We seek, urge and exhort you … that you be sent as judges into different districts to preach to the clergy and people gathered together where it seems useful to you. And using those discrete people that are known to you, seek out diligently those who are heretics or reputed to be heretics. We concede [to your lay helpers] the free faculty of wielding the sword against enemies of the faith.¹⁷

What made the inquisitors novel was that they used the latest legal techniques to investigate heresy. This was a consequence of the new interest in Roman law at the university of Bologna that we touched on at the end of the last chapter. Until the thirteenth century, most countries continued to use the old legal codes that they had followed for generations. In these codes, the legal process was started when a member of the public made a formal ‘accusation’. When criminal accusations were made, the defendant had a number of ways in which he could demonstrate his innocence. One was to produce character witnesses who would demand an acquittal. Another was to undergo trial by ordeal. In neither case did real evidence have much relevance. Furthermore, the accuser was vulnerable to punishment for defamation if the defendant was acquitted. Someone with a bad reputation could never win a legal battle against someone who was generally thought of as honest. The Church frowned on trial by ordeal and banned the clergy from participating in it in 1215.¹⁸

With the new system of ‘inquisition’, the ‘accusation’ method of justice was eventually abandoned altogether. Instead, the authorities appointed a magistrate to investigate the crime, interview witnesses, examine the evidence and reach a verdict. In the case of heresy, the magistrate was an inquisitor and appointed by the Pope. The system was an obvious improvement over the old ways and slowly spread to secular justice too. In fact, it worked so well that it still forms the backbone of criminal investigation in continental Europe to this day.¹⁹

The inquisitors had to follow strict rules and reserved the most serious punishment only for heretics who were obstinate in their error or were repeat offenders. Everyone had a second chance. When an inquisitor arrived in an area, he began his mission by declaring that he would deal mercifully with all heretics who gave themselves up. He then followed through any leads that he had received, made arrests, carried out interrogations and declared who he thought was guilty. While inquisitors had a special dispensation from the Pope to use torture, this was rare.²⁰ The popular image of dank inquisitorial dungeons equipped with a variety of imaginative means of torment is a later myth, popularised after the Reformation by Protestant writers.²¹ If the inquisitor found someone guilty of heresy, then they had an opportunity to recant and perform a penance. Most people took this option and the resulting penances were often quite lenient. However, those convicted of heresy were on notice that the inquisitors would deal with a second offence much more severely. In that case, as relapsed heretics, they could face life imprisonment or worse. In the same boat as repeat offenders were those whom the inquisitor convicted but who refused to admit the error of their ways. In the most serious cases, the inquisitor would hand over relapsed and obstinate heretics to the secular authorities. Officially, the Church could not execute a suspect but inquisitors knew perfectly well what the fate of those they handed over to the secular arm would be.

In 1017, King Robert II (972–1031) of France had instituted burning as the punishment for heresy and the penalty spread through most of Catholic Europe.²² Nevertheless, it was not universal. In England, parliament did not enact heresy laws until the fifteenth century, while in Venice the penalty was death by drowning.²³ The authorities also deemed that Amaury himself had continued to espouse his heretical ideas even after he had repented in front of the Pope. For that reason, they exhumed and burnt his body – gruesome revenge on a man who had caused so much trouble even after he was dead.

The inquisitors of the Middle Ages have a deservedly poor reputation. There is no defence for subjecting people to an agonising death over religious disagreements. Executions were uncommon (occurring in about five per cent of cases in the surviving records)²⁴because when it came to the crunch, few people wished to be martyrs. There was, however, another side of the struggle for doctrinal orthodoxy. To effectively combat heresy, the church realised that a two-pronged approach was necessary. It was no good convicting people for false beliefs if they had no idea what they were supposed to believe. The answer was to provide good preaching for the common people so that they had the chance to learn the rudiments of the orthodox Catholic faith.

The New Orders: Dominicans and Franciscans

Dominic Guzman (1170–1221), later canonised as St Dominic, was one of those who could see that the Church was just not doing its job of spreading the faith well enough. Priests were absent from their parishes, the bishops were too interested in secular power and the Church as a whole could be a pretty unedifying spectacle. No wonder, Guzman thought, that the common folk were seeking their spiritual nourishment from alternative sources. He also realised that the men sent out to preach the word of God had to be of unimpeachable virtue. It was no use telling peasants about Jesus if you were clearly not taking much notice of his message yourself. To help solve these problems, Guzman founded the Order of Preachers in 1216. Its job was to combat the spread of heresy among ordinary people by going out and explaining Christianity. His new order dressed in a simple black habit (and hence they were known as the Blackfriars), lived on charity and did their work among the poor and dispossessed, often in cities rather than the countryside.²⁵ The Blackfriars had to be learned enough to promulgate and defend the Christian faith, so they began to take advantage of the educational opportunities available at the new universities.²⁶

Guzman’s idea was a great success. Quite soon, his order took on the name of its founder and became the Dominicans, although to this day they still have the letters OP (for Order of Preachers) after their names. Their mixture of piety and fearsome intellect meant that the Dominicans were also the perfect people to act as the Pope’s inquisitors. The zeal with which they preached and acted against heresy earned them the nickname ‘hounds of God’ (a pun on the Latin version of their name, domini canes), of which they were very proud. Frescoes in Dominican churches, like Santa Maria Novella in Florence, sometimes show St Dominic surrounded by his dogs sniffing out heretics.

At about the same time as Dominic was setting up his order of preachers, Francis of Assisi (1181–1226) launched his own evangelising mission in the form of the Order of the Friars Minor, or Franciscans. They have always enjoyed a rather less sinister reputation than the Dominicans, partly because St Francis was such a gentle soul himself. However, after a slightly slower start, the Franciscans also began to seek out the best education and produced several towering thinkers to match the best of the Dominicans. The Franciscans also worked as inquisitors, although they never took to it quite as well as the Dominicans. This was partly because the Franciscans spent the first century of their existence torn apart by doctrinal disputes about just how poor and beggarly they needed to be.²⁷ When many members of the order stood accused of heresy themselves, the Franciscans were not best placed to lecture anyone else on orthodoxy.

It may well have been the Dominicans who were behind the lifting of the ban on Aristotle’s natural philosophy in 1231. They had quickly realised that they needed Aristotle when they started to dispute with Cathar heretics. Cathars, to recap, were dualists who believed that the material world was evil and created by a wicked god. It was no good pointing out to them that the first chapter of Genesis clearly states that the one God created the world and said that it was good. The Cathars did not revere the Old Testament and thought that the God it described was a completely different one from the God portrayed in the New Testament.²⁸ It is difficult to have an argument without any common ground. Luckily, Christian and Cathar alike respected the works of Aristotle. Using them, the Dominicans could debate and prove that the Cathars were wrong to think that the material world was wicked.²⁹

For example, although Aristotle did not believe that the world had been created by God, he did believe that nature is essentially benign. His books on natural history provide case after case to show how nature provides animals with the niche in which they can best live their lives. Aristotle’s world is beautiful and exquisitely crafted for the benefit of the creatures that inhabit it. There was no way, the Dominicans insisted against the Cathars, that this fecund world could be the product of an evil deity.

To use his works successfully, the Dominicans had to know their Aristotle back to front, so it was necessary that his works remained a central part of the university syllabus. But what should be done about the obvious dangers of his unorthodox opinions? Luckily, Christians had centuries of practice in dealing with pagan philosophy. There was a debate in the early church about whether it was permissible to read Plato. Some extremists advocated ignoring Greek philosophy altogether and insisted that everything that you needed to know was in the Bible. St Augustine of Hippo disagreed. He wrote:

Any statements by those who are called philosophers, especially the Platonists, which happen to be true and consistent with our faith should not cause alarm, but be claimed for our own use, as it were, from owners who have no right to them.³⁰

In other words, it was perfectly acceptable to pick and choose the most agreeable elements of pagan thought. Even if some of Aristotle was dangerous, that did not justify abandoning his works altogether. Rather, Christians should co-opt the parts of his philosophy that could serve Christianity. Everyone agreed that theology was still the most important branch of knowledge but natural philosophy now had a role as the servant of theology, or the ‘handmaiden’ as they put it in the Middle Ages.³¹ Being a handmaiden had some practical advantages, especially when serving the queen of the sciences. It meant that natural philosophy had a protected status in the universities because it was a prerequisite for the study of theology. In any case, that was the theory. As it turned out, despite the Pope’s lifting of the ban in 1231, the controversy about Aristotle rumbled on through the thirteenth century. Even with the handmaiden analogy, philosophers and theologians still could not agree where the line between their subjects was, nor to what extent reason should criticise or amend sacred doctrine. What everyone now needed were clear boundaries between the disciplines. Inevitably, it would be hard to agree where these should be.