The wizard, the popes, and the optics

fencing under a cross and a rainbow

An exploration of Roger Bacon: “Britain’s first scientist” and simultaneously a “magician”. Image credit: Imogen Edmundson.


It’s February 1592. You have just finished a long and smelly shift at the tannery. Needing something to take your mind off the rumours of plague, you settle on a relaxing theatre trip, yet the bear pits are full. The word “scientist” won’t exist for another 200 years but, nonetheless, the play you’re going to see is about somebody who is claiming to being one. Robert Greene’s The Honorable Historie of Frier Bacon and Frier Bongay has had rave reviews. It’s got everything: at least three duels, two quarrelsome Oxford students who manage to kill each other (Greene went to Cambridge), and a lazy servant who gets taken to hell to run a pub. Throughout, Friar Bacon works miracles, the crowning glory of which is his creation of a brass head that can answer any question. It’s a fantastic day out, and you can’t wait to come back and see the sequel when Mr Greene finishes it.

The real Roger Bacon, on the other hand, would have been appalled at Greene’s portrayal. A genuine and devoted Franciscan monk, he was more likely to be found buried in the Bible than consorting with demons. As for the magical head, the story had been told about Pope Sylvester II 100 years before Bacon’s birth and obviously has no basis in truth, regardless of the subject. If not a fearsome wizard, Bacon must have done something to achieve such posthumous notoriety. In reality, he held a position at the crest of a wave of progress in the field that would later become science. A footnote in scientific history, this surge is fascinating in its similarities and differences to modern science.

If not a fearsome wizard, Bacon must have done something to achieve such posthumous notoriety.

We don’t know for sure when Roger Bacon was born but we do know that he studied at Oxford (for those interested, he predates the college system—undeterred, Merton and Brasenose both claim strong connections). For about 20 years he seems to have moved between Oxford and Paris, the foremost universities of the day. He then joined the Franciscan monastic order in about 1257. This proved to be a spectacularly poor bit of timing: in 1260 a law was passed preventing monks from publishing any works without permission from superiors. Such permission was difficult to obtain: the decree was effectively a gagging order, as some monks in Spain had been getting embarrassingly heretical in public. Bacon had not published anything prior to this; it would not have seemed important at the time, but now the door was closed.

The pope remembered Bacon and commissioned him to produce a full summary of his thoughts on education. As the ban on publishing was still in place, the work would have to be done in secret and, conveniently, the pope also forgot to include any source of funding for the project.

All was not lost. In a testament to the importance of networking, a fleeting conversation with the papal ambassador Cardinal de Foulques sometime around 1263 became something much more momentous: Cardinal de Foulques was chosen as Pope Clement IV in 1265 as an unexpected compromise candidate. The pope remembered Bacon and commissioned him to produce a full summary of his thoughts on education. As the ban on publishing was still in place, the work would have to be done in secret and, conveniently, the pope also forgot to include any source of funding for the project. These were hardly auspicious conditions.

Despite the restrictive circumstances, Bacon set to work with a vengeance. The next three years saw the repeal of the publishing ban, the completion of Bacon’s imaginatively named Opus Majus (Greater Work) and associated writings, and the death of the pope who started it all in rapid succession. At the end of this bizarre episode, Bacon had written well over a million words explaining his views on nearly every scholarly subject. He would continue to study and write for another 30 years, but the Opus Majus remains his most significant work.

At the end of this bizarre episode, Bacon had written well over a million words explaining his views on nearly every scholarly subject.

As one would expect, the Opus Majus covers a wide range of subjects. Theology and ethics are at its core, but linguistics and even music make an appearance. There is also an early argument in favour of calendrical reform (the flaws Bacon points out would not be remedied until the Gregorian calendar over 200 years later—perhaps things would have been different had Clement lived longer). The scientific sections are extensive. On closer inspection, though, the contents are largely an intelligent synthesis of existing works. Aristotle underlies every section and Bacon draws much of his optics from the earlier Islamic scholars Ibn al-Haytham and Ibn Rushd. Bacon is often credited with the discovery of gunpowder in the Catholic West. The reality is that his is one of the first descriptions of gunpowder, but he did not invent it, merely observing a demonstration with a sample likely obtained from the Mongol Empire. An artillery officer became convinced that there was a recipe for gunpowder hidden in plain sight as a cryptogram in his writings. The letter in question is likely not by Bacon and the supposed recipe does not make a functional gunpowder. Nonetheless, the passage supports a relevant point: Bacon’s approach deviates from 12th century orthodoxy in the weight he places on the importance of new observations of the world. Scholarship at the time was still largely tied up in interpreting the wisdom of the past. The concept is not original, though—in Oxford, Robert Grosseteste had started thinking in this vein 50 years earlier. Like Isaac Newton, 400 years later, Bacon stood on the shoulders of giants. 

Bacon’s approach deviates from 12th century orthodoxy in the weight he places on the importance of new observations of the world. Scholarship at the time was still largely tied up in interpreting the wisdom of the past.

Aristotle needs no introduction, and an explanation of 11th and 12th century Islamic scholarship would need at the very least an article to itself. The key point regarding the 13th century is that despite most of these writings being well over a century old, they were very new to Catholic Europe. Academic discussion in universities had, up to this point, largely concerned theology and used the Bible as its sole primary source. This was all changed by military success in Spain, particularly the bloodless capture of the city of Toledo in 1085. Large amounts of Arabic literature were now accessible to Catholic scholars, being translated in that city. The newly available texts included translations of Aristotle as well as the work of Arabic scholars. Some of Aristotle’s work had been known in Europe, but only from partial Roman accounts—the Arabic versions were far superior. Centuries earlier, the Arabs had conquered Egypt, which had been effectively Greek since the time of Alexander the Great. The direct transmission through literate societies was much more complete than what had survived the Germanic invasions of the Western Roman Empire.

The initial reaction in Paris, Europe’s academic centre at the time, was a 1210 prohibition on the study of these texts. Despite this, by 1250, it would become commonplace to refer to the works of such non-Christian natural philosophers. A key figure in this transition was Albertus Magnus (in fact Saint Albertus Magnus, an accolade very few modern academics can claim). He wrote extensively about the new material, adding his own comments, writing some sections he felt were missing (notably minerology) and unifying the ideas with current theology, crucial for study to continue. Roger Bacon did not think much of Albertus Magnus, writing in his Opus Minus (also sent to the pope) that his writings are replete with an infinite number of errors and much shallowness’. He also describes Magnus’ positive reception in Paris as a ‘monstrosity’. These quotations give an idea of Bacon’s communication style—colourful and dramatic—and begin to explain why he attracted more attention in later years than the older Grosseteste, from whom many of his ideas originate.

These quotations give an idea of Bacon’s communication style—colourful and dramatic—and begin to explain why he attracted more attention in later years than the older Grosseteste, from whom many of his ideas originate.

Robert Grosseteste was an Englishman born around 1168 who spent much of the early part of his career lecturing at Oxford. During his time in Oxford, free of the Parisian ban, he studied and extended the ideas coming from Toledo. He was not as systematic as Albertus Magnus. Within his work, particularly a commentary on Aristotle’s Posterior Analytics, Grosseteste outlined the importance of working from observations to general laws, but also from such laws to predictions that could be verified. He called these processes “resolution and composition” and emphasised the importance of experimentation to both.

There are few clear examples of this process in his work, despite many other remarkable ideas, notably a cosmology that involved a constantly expanding universe. He cannot have had much time: in 1235 he was chosen as Bishop of Lincoln, which was a much more important city then than it is now. The remainder of his life was largely occupied with theological politics. Grosseteste could be as combative as Bacon sometimes, notably in a conflict with Pope Innocent IV over a particularly hands-on Archbishop of Canterbury. The 1250 encounter between bishop and Pope was so explosive that it inspired a persistent myth (often attributed to Matthew Paris). In the story, Grosseteste’s ghost takes revenge on the pope from beyond the grave, striking him with his crozier. The tale is even related in John Foxe’s influential Book of Martyrs in the 1560s. Grosseteste’s scientific writing is fairly restrained by comparison to Bacon’s and does not contain much evidence of this more dramatic side of his personality.

There are few clear examples of this process in his work, despite many other remarkable ideas, notably a cosmology that involved a constantly expanding universe.

By contrast to his treatment of Albertus Magnus, Bacon makes no secret of his respect for Grosseteste. Despite seemingly never overlapping at Oxford, it is not unreasonable to think of Bacon as a disciple of sorts, propagating Grosseteste’s ideas. Bacon’s impact, then, comes not from his originality but from his presentation, both in his personal interactions (which secured him the commission to write the Opus Magnus in the first place) and his ambitious and engaging written work.

To completely dismiss Opus Majus as a work of summary is unfair, though. It contains a great number of original ideas. Perhaps the most remarkable from a scientific point of view is a method for measuring the maximum elevation of a rainbow. Bacon describes using an astrolabe (a device for measuring the height of an object above the horizon) to observe the position of both the Sun and bow peak. Repeated measurements and a calculation lead to the prediction of a theoretical maximum of 42 degrees. This value is entirely correct. Apparently original, the experiment by which the result was obtained would not seem out of place in the 17th century.

It would seem as if great progress were being made, but within a few centuries, Grosseteste’s ideas were all but forgotten and Bacon was a wizard. The causes of this lull are of course multifaceted, but a major part of the puzzle seems to be communication. The ideas of these scholars were transmitted in works with a very narrow circulation as without the printing press, copying an academic work was a non-trivial task for each copy. Moreover, oral communication of philosophy was largely restricted to the clerical class. Scientific discoveries were communicated neither to the nobility nor the peasantry. For the church of the time, understanding was not necessary to Christian faith and indeed could open the church up to criticism, threatening its secular power. That any trace of Bacon’s scientific work survives though to Greene’s play is a testament to the power of his conviction and strength of personality.

Between these factors hindering communication, the benefits of progress felt by wider society were minimal to say the least. Not only that, but the range of voices that could contribute to the discussion and extension of philosophical ideas was not wide, and daring philosophies, such as experiment, were unable to find many adherents. It is telling that when the restrictions were swept away by the intertwined events of the invention of the printing press and the Reformation, a period of legendary innovation was swift to follow—the Renaissance. Some modern scientists may bemoan the emphasis now placed by funding bodies on measures of impact: public engagement work and concrete societal benefits. The 13th century stands as a cautionary tale that scientists neglect communication with the non-academic world at their peril.