Roger Bacon
Roger Bacon was born in Ilchester in Somerset, England, in about 1220. It is believed that his family were fairly prosperous. Roger was not the eldest son, so the inheritance from the family would never be his. He received some basic tutoring by the local priest, in reading, simple arithmetic and the essentials of Latin. (1)
Bacon's father had a high regard for learning and he was willing to finance his sons education. At this time local schools were springing up around the country to cope with the rising demand for clergymen, lawyers and administrators. However, his father thought he should be sent to the only instituation that had a truly international reputation - the University of Oxford, that had been established in 1096. When he reached the age of thirteen, Roger was sent away to get the best education money could buy. (2)
The rival education institution was the University of Cambridge. This had been established after an incident that had taken place in Oxford in December 1209. Three students were sharing an house. Although the students were supposed to maintain a chaste life they had not taken a vow of chastity, and one of them had a mistress. After a heated argument he killed his girlfriend. He fled and when news of her killing brought an angry mob onto the streets. The mayor panicked and he decided that action was needed quickly if they were to keep control of the town. The two students that remained in the room, were seized and hanged in front of the mob. The masters of University of Oxford were furious as every student was a cleric in the minor orders and were subject to the law enforcement of the Church. In protest, seventy masters departed from Oxford, taking hundreds of students with them. (3)
Dispite this exodus, by the time Bacon went to university, Oxford was considered to be superior to Cambridge. It had faculties of arts, theology, law and medicine. Although the university was open to any young man who had the money to pay, there was one unbreakable entry requirement: students had to take on minor orders in the Church. This made them subject to Church law and on entry he had to have a tonsure (a haircut that gave you an artificial bald spot). It is said to have its origins in the Roman custom of shaving the heads of slaves, demonstrated that the wearer was a slave to Christ. (4)
Bacon enjoyed his time at university. There were no halls or colleges at this time. Students lived in lodging houses, renting rooms from people living in the town. Lectures took place in large rented rooms around Oxford. Later he would talk about the value of a good education: "To neglect knowledge is to neglect virtue; the intellect lightened by the flame of goodness cannot help but love it. Love is only born of knowledge. Reason is the guide of a right will. It is reason which leads us to salvation." (5)
Bacon spent six years studying to complete his Bachelor of Arts, and another two years to get his Master of Arts. He then became a master in the Faculty of Arts where he majored in philosophy. In the early 1240s, Bacon moved to the University of Paris. It was considered to be the greatest university of the time. It also enjoyed the special protection of the papacy. Latin was the language of academic discourse and the university attracted students from all over the world. One of the main reasons he was invited to Paris was his expertise on Aristotle. Since before Bacon's birth, several of Aristotle's books, particularly those on natural philosophy, had been banned in Paris because the Church authorities felt that the views of the great Greek philosophy were dangerously close to heresy. After more than thirty years of being banned there was a dearth of masters with the appropriate knowledge to pass on Aristotle's wisdom. (6)
It has been argued that Bacon became disillusioned with his teaching Aristotle's ideas. "In the twenty years in which I have laboured specially at the study of wisdom, disregarding the crowd's approach, I have spent more than two thousand pounds on these matters". (7) George Molland believes that his early Aristotelian works deriving from his Paris lectures may be seen as representative of the "crowd's approach". His new approach may loosely be described as more "scientifically" and technologically oriented, and was strongly influenced by Robert Grosseteste and the Franciscan school at Oxford, and especially Adam Marsh. Another possible influence was Albertus Magnus, one of the greatest scholars of the Middle Ages. who also taught in Paris. (8)
Bacon's most important influence was Petrus Peregrinus de Maricourt, French scholar who conducted experiments on magnetism and wrote the first extant treatise describing the properties of magnets. He explained how to identify the poles of the compasses. Maricourt also described the laws of magnetic attraction and repulsion. In one of his letters he argued that by using his compass "you will be able to direct your steps to cities and islands and to any place whatever in the world." He was also impressed by Maricourt because "he neglects all honours and riches". (9)
Bacon described Maricourt as the "master of experiment" and wrote in Opus Tertium (c. 1267): "He (Maricourt) gains knowledge of matters of nature, medicine, and alchemy through experiment, and all that is in the heaven and in the earth beneath... Moreover, he has considered the experiments and the fortune-telling of the old witches, and their spells and those of all magicians. And so too the illusions and wiles of all conjurors; and this so that nothing may escape him which ought to be known, and that he may perceive how far to reprove all that is false and magical." (10)
While in Oxford he thought of himself as a philosopher. But after coming into contact with people like Magnus and Maricourt he began speculating on how the world functioned. Witnessing the power of experiment through seeing these people in action convinced him that here was a field that was grossly undervalued. Bacon saw this as a wonderful opportunity to make himself an authority on science. He thought he would have more opportunity to do this in Oxford. (11)
Roger Bacon and Mathematics
At this time he came across a rare book, Secretum Secetorum (The Secret of Secrets). It claims to be a letter from Aristotle to his student Alexander the Great on an encyclopedic range of topics, including statecraft, ethics, physiognomy, astrology, magic, alchemy, medicine, hygiene, health, diet, cooking, bathing, herbs and the magical properties of plants. Modern scholarship finds it likely to have been a 10th-century work composed in Arabic. Translated into Latin in the mid-12th century by Philip of Tripoli, it was influential among European intellectuals during the High Middle Ages. This led some people to claim that Bacon's contact with the Secretum Secretorum was the key event pushing him towards experimental science. (12)
The book demonstrated the powerful practical benefits of a knowledge of nature. It showed that the natural sciences were not just a matter of philosophical wonder, but also provided a pathway to success in overcoming military and civil problems. Most importantly, the book suggested that a knowledge of nature was an essential part of understanding God. "In one of its more mystical sections, it tells how the sons of Seth (the son of Adam) were once the holders of all knowledge, which was subsequently lost and was only partially rebuilt by the ancient Greeks, the Arabs, and now the Christian academics. The book persuaded Bacon that the greatest goal for any searcher after truth was to regain this universal understanding." (13)
George Henry Lewes has suggested that this book resulted in Roger Bacon becoming a disciple of the Arabs. "He also insisted on the primary necessity of Mathematics, without which no other science can be known; yet by Mathematics it is clear that he meant something very different from what we mean, including under that head even dancing, singing, gesticulation, and performance on musical instruments…. Roger Bacon, a man of almost universal genius, and who wrote on almost every branch of science. (14)
Roger Bacon emphasised the connection between mathematics and science. At the time people were highly suspicious of mathematics. The Latin word mathesis could mean scientific knowledge or magic (charms, illusions and fortune-telling). In the 15th century "calculating" was often used to mean employing magic, while in the 17th century there were reports of "mathematical" books being burnt because they were being confused for "conjuring" books. (15)
Bacon was well aware of the danger of mathematics being confused with magic. "Philosophers universally condemn the madness of these false mathematicians". They subscribed to this deterministic astrology, but also because they attempt to use black magic to help bolster their power, they "defile their studies in regard to the heavenly bodies by circles and figures and very silly characters and very foolish incantations". Bacon claimed these false mathematicians used their knowledge to control their followers: "Moreover, they have recourse to fraud in their acts, perpetrated by means of collusion, darkness, fraudulent instruments, or sleight of hand, in which they know there is deception, and they do many things to be wondered at by the foolish by these means, in which matters the influence of the heavens is not operative... they know in their hearts that their statements to others attributing influence to the heavens have no truth." (16)
Bacon was himself no mathematician as he did not advance knowledge of mathematics. Why he was important was because he made it clear that scientific breakthroughs are underpinned by mathematics. (17) "For the things of this world cannot be made known without a knowledge of mathematics. For this is an assured fact in regard to celestial things, since two important sciences of mathematics treat of them, namely theoretical astrology and practical astrology. The first... gives us definite information as to the number of the heavens and of the stars, whose size can be comprehended by means of instruments, and the shapes of all and their magnitudes and distances from the earth, and the thicknesses and number, and greatness and smallness… It likewise treats of the size and shape of the habitable earth… All this information is secured by means of instruments suitable for these purposes, and by tables and by canons... For everything works through innate forces shown by lines, angles and figures." (18)
The Scientific Method
The traditional approach to natural philosophy was to take what was observed and analyse it by pure thought. Bacon decided to change this approach by testing out different hypotheses. This was an expensive process: "During the twenty years in which I have laboured specially in the study of wisdom, after abandoning the usual methods, I have spent more than £2,000 on secret books and various experiments, and languages and instruments and mathematical tables etc." At the time £2,000 would buy about 500 houses. (19)
It has been claimed that Bacon changed "natural philosophy" into what we now call "science". Bacon was an empiricist: he argued that "theories supplied by reason should be verified by sensory data, aided by instruments, and corroborated by trustworthy witnesses". To some historians of ideas, therefore, he appears as "an anomaly in his age, a modern before modern times, who would have been more at home with Galileo and Newton in the seventeenth century as a colleague in the rise of science". (20)
In On the Marvellous Power of Art and Nature (c.1260) Bacon set out a catalogue of inventions that had been constructed in antiquity and had been lost. This including a flying machine. The most basic form of workable airborne device, the kite, had been around since the fifth century BC, but it was Bacon who gave a hint of the principle on which the modern fixed-winged areo-plane functions, pointing out that air should be able to support it in the same way that water supports a boat. This eventually inspired the English inventor George Cayley, who drew up plans for a fixed-winged powered aircraft in 1799. (21)
Bacon also predicted the invention of a fast-moving ship: "It is possible that great ships and sea-going vessels shall be made which will be guided by one man and will move with greater swiftness than if they were full of oarsmen." (22) Technology had not changed for thousands of years. To make a boat move through the water took the effort of men pulling on oars or the force of the wind on its sails. It was not until 600 years after Bacon's death that steam engines were used in ships. (23)
Bacon was also the first person to suggest the modern car. He thought that self-propelled cars were possible because he assumed that something similar had previously existed, in the shape of the mythical currus falcati. "It is possible that a car shall be made which will move with inestimable speed, and the motion will be without the help of any living creature. Such, it is thought, were the currus falcati which the ancients used in combat." (24) Like the self-propelled ship, Bacon's horseless carriage required the steam engine to make it possible, but it was truly brought into existence in 1885 when Karl Benz and Gottlieb Diamler. (25)
Opus Majus
Bacon was not encouraged to write because the Franciscan order feared the spread of possibly heretical apocalyptic tracts. As Bertrand Russell pointed out: "Bacon was constantly getting into trouble through being suspected of heresy and magic." (26) To overcome this problem, he had a meeting with Pope Clement IV, He agreed that he should produce Opus Majus (Latin for "Great Work"), to explain the work that Bacon had undertaken. The 840-page treatise ranges over all aspects of natural science. (27)
J. H. Bridges has argued: " Throughout the Opus Majus there is an orderly arrangement of the subject-matter formed with a definite purpose, and leading up to a central theme, the consolidation of the Catholic faith as the supreme agency for the civilization and ennoblement of mankind. For this end a complete renovation and reorganization of man's intellectual forces was needed. After a brief exposition of the four principal impediments to wisdom - authority, habit, prejudice, and false conceit of knowledge - Bacon proceeds in his second part to explain the inseparable connexion of philosophy with the highest truths of religion... The second condition was the application of mathematical method to all objects of study, whether in the world or in the Church... it mathematics raises the understanding to the plane at which knowledge can be distinguished from ignorance. Without it, other sciences are unintelligible. It reveals to us the motions of the heavenly bodies, and the laws of the propagation of force in things terrestrial, of which the propagation of light may be taken as a type; without it we are incapable of regulating the festivals of the Church; we remain in ignorance of the influences of climate upon character; of the position of cities and of the boundaries of nations whom it is the function of the Catholic Church to bring within her pale, and to control spiritually… But mathematical method, though essential, is insufficient. It must be supplemented by the method of experiment." (28)
The book included Bacon's research into optics. He had clearly read the work of Ibn al-Haytham (Latinized as Alhazen), an Arab mathematician, astronomer, and physicist (c. 965 - c. 1040): "Roger Bacon, a man of almost universal genius, and who wrote on almost every branch of science. He frequently quotes Alhazen on the subject of optics, and seems to have carefully studied his writings, as well as those of other Arabians, which were the fountains of natural knowledge in those days, and which had been introduced into Europe by means of the Moors in Spain... Notwithstanding the pains this great man took with the subject of optics, it does not appear that, with respect to theory, he made any considerable advance upon what Alhazen had done before him." (29)
Bacon began with the idea of using mirrors and lenses so that "one appears as many, one man an army". He suggested that this could be used in war so that "infinite terror may be cast upon a whole city or upon an army so that it will go entirely to pieces". This was never used but he did describe optical devices that would come into use hundreds of years later, where "lenses are contrived so that the most distant objects appear near at hand." These lenses would be able to "read the smallest letters at an incredible distance, we may see objects however small they may be, and we may cause the stars to appear wherever we wish." (30)
Joseph Priestley also argues that Bacon was heavily influenced by the Arabs: "In his Opus Majus he demonstrates, that if a transparent body, interposed between the eye and an object, be convex towards the eye, the object will appear magnified. This observation our author certainly had from Alhazen... this writer (Bacon) gives us figures, representing the progress of rays of light through his spherical segment, as well as endeavours to give reasons why objects are magnified... From the writings of Alhazen and these observations and experiments of Bacon together, it is not improbable that some monks gradually hit upon the construction of spectacles, to which Bacon's lesser segment, not withstanding his mistake concerning it, was a nearer approach than Alhazen's... Whoever they were that pursued the discoveries of Bacon, they probably observed, that a very small convex glass, when held at a greater distance from a book, would magnify the letters more than when it was placed close to them, in which position only Bacon seemed to have used it. In the next place, they might try whether two of these small segments of a sphere placed together, or a glass convex on both sides, would not magnify more than one of them. They would then find, that two of these glasses, one for each eye, would answer the purpose of reading better than one; and lastly they might find, that different degrees of convexity, suited different persons. It is certain that spectacles were well known in the 13th century, and not long before... It would certainly have been a great satisfaction to us to have been able to trace the actual steps in the progress of this most useful invention, without which most persons who have a taste for reading must have had the melancholy prospect of passing a very dull and joyless old age; and must have been deprived of the pleasure of entertaining themselves by conversing with the absent and the dead, when they were no longer capable of acting their part among the living." (31)
He wrongly claimed that Julius Caesar used telescope to "discover the position and arrangement of the camps and towns of Brittany" does not make his concept any less remarkable. He understood as few had done before how the primitive lenses and mirrors then in existence bent light rays. Leonardo da Vinci followed him in referring to the possibility of making telescopes and microscopes, but the first known examples would not be made until 300 years later. It was not until the end of the sixteenth-century that Leonard Digges and his son, Thomas Digges, first demonstrated a telescope and it was around 1590 when Zacharias Janssen, constructed a microscope. (32)
Bacon went on to describe the possibility of channelling light to kill people during warfare. "A device by which rays of light are led into any place that we wish and are brought together by refractions and reflections in such fashion that anything is burned which is placed there. And these burning glasses function in both directions, as certain authors teach in their books." (33)
Bertrand Russell was critical about some of Bacon's theories: "Roger Bacon was not greatly admired in his own day, but in modern times has been praised far beyond his deserts. He was not so much a philosopher, in the narrow sense, as a man of universal learning with a passion for mathematics and science. Science, in his day, was mixed up with alchemy, and thought to be mixed up with black magic. He was encyclopaedic in his learning, but not systematic." However, he did believe he was a very "good mathematician". (34)
Bacon pointed out that mathematics was important to the scientist: "Mathematics is the gate and key of the sciences... Neglect of mathematics works injury to all knowledge, since he who is ignorant of it cannot know the other sciences or the things of this world. And what is worse, men who are thus Ignorant are unable to perceive their own ignorance and so do not seek a remedy.... The great power of mathematics can build a spherical instrument, like the artifice of Ptolemy in Almagest, in which all heavenly bodies are described veraciously as regards longitude and latitude, but to make them move naturally in their diurnal movement is not within the power of mathematics. A faithful and magnificent experimenter might aspire to construct an instrument of such materials and of such an arrangement that it would move naturally in the diurnal motion of the heavens." (35)
Bacon also explored the manufacture of gunpowder (also known as black powder). It consists of a mixture of sulfur, charcoal and potassium nitrate (saltpeter). The sulfur and charcoal act as fuels while the saltpeter is an oxidizer. (36) Bacon was the first one in Europe to explain the explosive force of gunpowder. "A moderate amount of proper material, of the size of the thumb, will make a horrible sound and violent coruscation" This would create "the sound of thunder... with greater resulting horror than if it had been produced by natural causes." (37)
Bacon was unaware that gunpowder was invented in 9th-century China. Originally developed by the Taoists for medicinal purposes, gunpowder was first used for warfare about 904 AD. (38) As Brian Clegg points out: "There were limits to Bacon's vision. He did not conceive of the ability of gunpowder to blast a projectile, a discovery that would change the face of weaponry for ever. Even so, his was the first real insight into the military value of black powder and the wider capabilities of science to make a difference to everyday life." (39)
It has been argued that Bacon was not a great experimentor himself, though he did conduct more experiments than some critics would acknowledge. He was especially active in the study of the rainbow. In Opus Majus he quotes the work of Aristotle, Seneca and Avicenna: "I use the example of the rainbow and of the phenomena connected with it, of which sort are the circle around the sun and the stars, likewise the rod lying at the side of the sun or of a star which appears to the eye in a straight line... called the rod by Seneca, and the circle is called the corona, which often has the colours of the rainbow. But neither Aristotle nor Avicenna, in their Natural Histories, has given us knowledge of things of this sort, nor has Seneca, who composed a special book on them. But Experimental Science makes certain of them. The experimenter… considers rowers and he finds the same colours in the falling drops dripping from the raised oars when the solar rays penetrate drops of this sort. It is the same with waters falling from the wheels of a mill; and when a man sees the drops of dew in summer of a morning lying on the grass in the meadow or the field, he will see the colours. And in the same way when it rains, if he stands in a shady place and if the rays beyond it pass through dripping moisture, then the colours will appear in the shadow nearby; and very frequently of a night colours appear around the wax candle. Moreover, if a man in summer, when he rises from sleep and while his eyes are yet only partly opened, looks suddenly toward an aperture through which a ray of the sun enters, he will see colours. And if, while seated beyond the sun, he extend his hat before his eyes, he will see colours; and in the same way if he closes his eye, the same thing happens under the shade of the eyebrow; and again, the same phenomenon occurs through a glass vessel filled with water, placed in the rays of the sun. Or similarly if any one holding water in his mouth sprinkles it vigorously into the rays and stands to the side of the rays; and if rays in the proper position pass through an oil lamp hanging in the air, so that the light falls on the surface of the oil, colours will be produced. And so in an infinite number of ways, as well natural as artificial, colours of this sort appear, as the careful experimenter is able to discover." (40)
Roger Bacon explains how experimental science can contribute to understand rainbows: "He describes using prisms and other shapes of glass to generate small rainbows. He explains how measurements can be made to show how the rainbow functions: the experimenter measures the angular distance of the Sun above the horizon to find the angle at which the rainbow effect cuts out... Where reasoning has been used to reach conclusions, experiment can (and should) be used to test the validity of those conclusions. What's more, he states very specifically that theoretical knowledge could not and should not be the only route to progress. Experience yields new instruments and experiments provide new data." (41)
Linguistics
In Opus Tertium (c. 1270) Roger Bacon pointed out the importance of language in philosophy. "Knowledge of languages is the first gateway to wisdom, especially for the Latins, who possess no theological or philosophical texts other than those composed in a foreign tongue. For that reason, everyone ought to know languages, needs to study them and understand their science. One cannot come to know them by natural means because they are dependent on persons' pleasure and they vary according to their will." (42)
Knowing other languages was important for science because most of their source works were written in something other than Latin - particularly Hebrew, Greek, and Arabic, sometimes called the "wisdom languages". A scientist could not rely on translations into Latin available at the time because of inaccuracies. "It is impossible that the peculiar quality of one language should be preserved in translation into another... Therefore an excellent piece of work in one language cannot be transferred into another as regards the perculiar quality that is possessed of the former." (43)
Language also had practical application to the Church. He was highly critical of those who preached their Latin sermons parrot-fashion, not really understanding what they themselves were saying, and of those who went out to preach to foreigners without doing so in the listeners' mother tongue. He suggested that if you wanted to preach to your congregation, or to trade with foreigners, or to attempt to convert infidels, there is no point in trying to do so without learning the appropriate language. (44)
As he pointed out in Opus Majus (c. 1267): "A knowledge of languages is very necessary for directing the commonwealth of the Latins (western Christians) for three reasons. One is sharing the utilities necessary in commerce and in business, without which the Latins cannot exist, because medicines and all precious things are received from other nations, and hence arises great loss to the Latins, and fraud without limit is practised on them, because they are ignorant of foreign tongues, however much they talk through interpreters; for rarely do interpreters suffice for full understanding, and more rarely are they found to be faithful. A second reason is the securing of justice... The third reason is the securing of peace among the princes of other nations and among the Latins that wars may cease." (45)
Bacon said a knowledge of language was useful in the service of the truth, in understanding matters of a speculative nature in philosophy and theology. Bacon believed that it is useful to understand language itself, how it works, its idioms, the way we construct verbal models and use signs, in order to understand better is being said. Bacon went on to point out when dealing with a scientific text it isn't enough for a translator to be well acquainted with the language. He also needs to have enough expertise in science to be able to make an effective translation. (46)
It has argued that Roger Bacon anticipated the theory put forward by Noam Chomsky of universal grammar because children only learn certain language-specific features of their native languages. He bases his argument on observations about human language acquisition, noting that there is a "poverty of the stimulus" - enormous gap between the linguistic stimuli to which children are exposed and the rich linguistic competence they attain. Bacon wrote that people had an underlying capacity for language: "grammar is one and the same in all languages, substantially, though it may vary, accidently, in each of them." (47)
Calender Reform
Our measurement of time has always been dependent on astronomical cycles. The daily turning of the Earth, the Moon's monthly progress through its phases, and the Earth's annual circuit of the Sun are all responsible for elements of the calendar. Bacon was fully aware of this: "But no one can certify in regard to times except the astronomer... and if we consider this matter, we shall find in many ways how necessary astronomy is." Bacon then went onto argue that the calendar used at the time was inaccurate: "I shall now introduce a subject... without which great peril and confusion cannot be avoided, although for long periods there has been manifold abuse in this matter." (48)
The calender had originally been established by Julius Caesar in 45 BC. At first the Romans had ten months spanning 304 days. Soon afterwards two more months (January and February) were added bringing the total number of days to 355. To cope with their year being around ten days too short, the Romans added an extra day to some of the months. Months alternated at 30 and 31 days, apart from February, which had 29 days in a normal year and 30 in a leap year. (49)
Bacon worked out that the calendar in use at the time made the year around 11 minutes longer than it was in reality. This error would mean that the calendar drifted farther away from the true progression of the seasons by a day every 125 or 130 years (it was actually 128 years). "All people educated in compitation and astronomy know it and deride the ignorance of the priests who maintain the actual state of the calendar... Arabs, Hebrews, and Greeks who live among Christians, as in Spain and Egypt and parts of the East and in many other regions of the world, abhor the folly shown by the Christians in their chronology and their celebrations." (50)
Bacon pointed out that there was an increasingly bad match between the religious calendar and reality and the Julian calendar should be reformed. (51) "What was the point of considering Sunday a holy day if every 125-130 years the day that was treated as special shifted to a different point in the week? And what of the most important holy day of the year, Easter Day, the celebration of Christ's resurrection? This too had begun to be celebrated on the wrong date thanks to the inaccuracies of the calendar.... Bacon reckoned that by 1361 the calendar would have dropped yet another day out of synchronization with the real world. He suggested that a day be missed out of the calender every 125 years." (52)
David Ewing Duncan, the author of The Calendar: The 5000-year Struggle to Align the Clock and the Heavens (2011), dedicates a chapter to Bacon entitled "A lone genius proclaims the truth about time". Duncan pointed out that he made "a strident missive" to Pope Clement IV in "an urgent appeal to set time right". However, he rejected the idea and it was not until 1582 that Pope Gregory XIII reformed the calendar. However, as Britain was not a Catholic country it did not bring in the reform to 1752. The Orthodox Christian countries did not adopt the Gregorian calender until the 20th century, the latest being Greece in 1924. (53)
Alchemy
Roger Bacon developed an interest in alchemy after reading the works of Ibn al-Haytham (Alhazen). Alchemy is a strange combination of chemistry and mysticism. It had its roots more than 1,500 years before Bacon't time and would continue to influence scientific thought until the 17th century. Alchemy began with the Greek philosophers' musings on the components of matter (the four elements of earth, air, fire and water). "As the application of heat seemed to be the best way of making elements combine and separate, a huge amount of effort was put into devising cycles of heating and cooling in the hope of achieving new combinations of the elements. It had been noticed that some parts of a substance would float away as air when heated, but if this air were cooled then the substances would re-form as liquids. This process, distillation, became an essential part of the alchemist's repertoire, as well as providing the basis for the production of alcohol." (54)
Bacon wrote a great deal about alchemy, but there is no evidence that he was much of a hands-on alchemist himself. He appears to be recording the findings of others rather than experimenting himself. There is certainly no evident to back up the claim by Evalyn Westacott, the author of Roger Bacon In Life And Legend (1953) that "Historians attribute to Bacon the discovery of phosphorus, manganese, bismuth, and the properties of antimony." (55)
Roger Bacon died in about 1292.
Primary Sources
(1) Roger Bacon, Opus Majus (c. 1267)
For the things of this world cannot be made known without a knowledge of mathematics. For this is an assured fact in regard to celestial things, since two important sciences of mathematics treat of them, namely theoretical astrology and practical astrology. The first … gives us definite information as to the number of the heavens and of the stars, whose size can be comprehended by means of instruments, and the shapes of all and their magnitudes and distances from the earth, and the thicknesses and number, and greatness and smallness… It likewise treats of the size and shape of the habitable earth… All this information is secured by means of instruments suitable for these purposes, and by tables and by canons... For everything works through innate forces shown by lines, angles and figures.
(2) Roger Bacon, Opus Majus (c. 1267)
Reasoning draws a conclusion and makes us grant the conclusion, but does not make the conclusion certain, nor does it remove doubt so that the mind may rest on the intuition of truth, unless the mind discovers it by the path of experience.
If in other sciences we should arrive at certainty without doubt and truth without error, it behooves us to place the foundations of knowledge in mathematics...
I shall draw... a figure (which all these matters are made clear as far as possible on a surface, but the full demonstration would require a body like the eye... The eye of a cow, pig, and other animals can be used for illustration, if anyone wishes to experiment.
(3) Roger Bacon, Opus Majus (c. 1267)
Everything in nature completes its action through its own force and species alone... as, for example, fire by its own force dries and consumes and does many things. Therefore, vision must perform the act of seeing by its own force. But the act of seeing is the perception of a visible object at a distance, and therefore vision perceives what is visible by its own force multiplied to the object…
Concerning the multiplication of this species, moreover, we are to understand that it lies in the same place as the species of the thing seen, between the sight and the thing seen, and takes place along the pyramid whose vertex is in the eye and base in the thing seen. And as the species of an object in the same medium travels in a straight path and is refracted in different ways when it meets a medium of another transparency, and is reflected when it meets the obstacles of a dense body; so is it also true of the species of vision that it travels altogether along the path of the species itself of the visible object.
(4) Roger Bacon, Opus Majus (c. 1267)
The Mathematics is the gate and key of the sciences. ... Neglect of mathematics works injury to all knowledge, since he who is ignorant of it cannot know the other sciences or the things of this world. And what is worse, men who are thus Ignorant are unable to perceive their own ignorance and so do not seek a remedy...
And because this Experimental Science is wholly ignored by the general run of students, for that reason I cannot convince people of its utility unless I show at the same time its excellence and its property. This science alone, then, knows how to test perfectly by experience what can be done by nature, what by the industry of art, what by imposture; what the incantations, conjurations, invocations, deprecations, sacrifices (which are magical devices) seek and dream of; and what is done in them, so that all falsity may be removed and that only the truth of art and nature be retained.
(5) Roger Bacon, Opus Majus (c. 1267)
I use the example of the rainbow and of the phenomena connected with it, of which sort are the circle around the sun and the stars, likewise the rod lying at the side of the sun or of a star which appears to the eye in a straight line... called the rod by Seneca, and the circle is called the corona, which often has the colours of the rainbow. But neither Aristotle nor Avicenna, in their ‘Natural Histories', has given us knowledge of things of this sort, nor has Seneca, who composed a special book on them. But Experimental Science makes certain of them. The experimenter… considers rowers and he finds the same colours in the falling drops dripping from the raised oars when the solar rays penetrate drops of this sort. It is the same with waters falling from the wheels of a mill; and when a man sees the drops of dew in summer of a morning lying on the grass in the meadow or the field, he will see the colours. And in the same way when it rains, if he stands in a shady place and if the rays beyond it pass through dripping moisture, then the colours will appear in the shadow nearby; and very frequently of a night colours appear around the wax candle. Moreover, if a man in summer, when he rises from sleep and while his eyes are yet only partly opened, looks suddenly toward an aperture through which a ray of the sun enters, he will see colours. And if, while seated beyond the sun, he extend his hat before his eyes, he will see colours; and in the same way if he closes his eye, the same thing happens under the shade of the eyebrow; and again, the same phenomenon occurs through a glass vessel filled with water, placed in the rays of the sun. Or similarly if any one holding water in his mouth sprinkles it vigorously into the rays and stands to the side of the rays; and if rays in the proper position pass through an oil lamp hanging in the air, so that the light falls on the surface of the oil, colours will be produced. And so in an infinite number of ways, as well natural as artificial, colours of this sort appear, as the careful experimenter is able to discover.
(6) Roger Bacon, Opus Tertium (c. 1270)
I have laboured much in sciences and languages, and I have up to now devoted forty years to them after I first learned the Alphabetum; and I was always studious. Apart from two of these forty years I was always engaged in study [or at a place of study], and I had many expenses just as others commonly have. Nevertheless, provided I had first composed a compendium, I am certain that within quarter or half a year I could directly teach a solicitous and confident person whatever I know of these sciences and languages. And it is known that no one worked in so many sciences and languages as I did, nor so much as I did. Indeed, when I was living in the other state of life [as a Magister], people marvelled that I survived the abundance of my work. And still, I was just as involved in studies afterwards, as I had been before. But I did not work all that much, since in the pursuit of Wisdom this was not required.
(7) Roger Bacon, Opus Tertium (c. 1270)
The strongest argument proves nothing so long as the conclusions are not verified by experience. Experimental science is the queen of sciences, and the goal of all speculation.
And this experimental science verifies all natural and man-made things in particular, and in their appropriate discipline, by the experimental perfection, not by arguments of the still purely speculative sciences, nor through the weak, and imperfect experiences of practical knowledge. And therefore, this is the matron of all preceding sciences, and the final end of all speculation.
(8) Roger Bacon, Opus Tertium (c. 1270)
One man I know, and one only, who can be praised for his achievements in this science. Of discourses and battles of words he takes no heed: he follows the works of wisdom, and in these finds rest. What others strive to see dimly and blindly, like bats in twilight, he gazes at in the full light of day, because he is a master of experiment. Through experiment he gains knowledge of natural things, medical, chemical, indeed of everything in the heavens or earth. He is ashamed that things should be known to laymen, old women, soldiers, ploughmen, of which he is ignorant. Therefore he has looked closely into the doings of those who work in metals and minerals of all kinds; he knows everything relating to the art of war, the making of weapons, and the chase; he has looked closely into agriculture, mensuration, and farming work; he has even taken note of the remedies, lot casting, and charms used by old women and by wizards and magicians, and of the deceptions and devices of conjurors, so that nothing which deserves inquiry should escape him, and that he may be able to expose the falsehoods of magicians. If philosophy is to be carried to its perfection and is to be handled with utility and certainty, his aid is indispensable. As for reward, he neither receives nor seeks it. If he frequented kings and princes, he would easily find those who would bestow on him honours and wealth. Or, if in Paris he would display the results of his researches, the whole world would follow him. But since either of these courses would hinder him from pursuing the great experiments in which he delights, he puts honour and wealth aside, knowing well that his wisdom would secure him wealth whenever he chose. For the last three years he has been working at the production of a mirror that shall produce combustion at a fixed distance; a problem which the Latins have neither solved nor attempted, though books have been written upon the subject.
(9) Roger Bacon, Opus Tertium (c. 1270)
All these foregoing sciences are, properly speaking, speculative. There is indeed in every science a practical side, as Avicenna teaches in the first book of his Art of Medicine . Nevertheless, of Moral Philosophy alone can it be said that it is in the special and automatic sense practical, dealing as it does with human conduct with reference to virtue and vice, beatitude and misery. All other sciences are called speculative: they are not concerned with the deeds of the present or future life affecting man's salvation or damnation. All procedures of art and of nature are directed to these moral actions, and exist on account of them. They are of no account except in that they help forward right action. Thus practical and operative sciences, as experimental alchemy and the rest, are regarded as speculative in reference to the operations with which moral or political science is concerned. This science is the mistress of every department of philosophy. It employs and controls them for the advantage of states and kingdoms. It directs the choice of men who are to study in sciences and arts for the common good. It orders all members of the state or kingdom so that none shall remain without his proper work.
(10) J. H. Bridges, The Opus Majus of Roger Bacon (1900)
Throughout the Opus Majus there is an orderly arrangement of the subject-matter formed with a definite purpose, and leading up to a central theme, the consolidation of the Catholic faith as the supreme agency for the civilization and ennoblement of mankind. For this end a complete renovation and reorganization of man's intellectual forces was needed. After a brief exposition of the four principal impediments to wisdom - authority, habit, prejudice, and false conceit of knowledge - Bacon proceeds in his second part to explain the inseparable connexion of philosophy with the highest truths of religion...The first condition… of a renovation of learning is the systematic study of at least three languages besides Latin, namely Hebrew, Greek, and Arabic. The second condition was the application of mathematical method to all objects of study, whether in the world or in the Church... it mathematics raises the understanding to the plane at which knowledge can be distinguished from ignorance. Without it, other sciences are unintelligible. It reveals to us the motions of the heavenly bodies, and the laws of the propagation of force in things terrestrial, of which the propagation of light may be taken as a type; without it we are incapable of regulating the festivals of the Church; we remain in ignorance of the influences of climate upon character; of the position of cities and of the boundaries of nations whom it is the function of the Catholic Church to bring within her pale, and to control spiritually… But mathematical method, though essential, is insufficient. It must be supplemented by the method of experiment. Experimental science governs all the preceding sciences…
To be able to speak the language of the schools with authority was the first condition of obtaining a hearing. But he was not slow to perceive that the men who taught this philosophy were, for the most part, wholly destitute of positive knowledge. They knew no language but Latin. Beyond the shreds of arithmetic, mensuration, and astronomy taught in the manuals of the Quadrivium, they were ignorant of mathematics. Of the possibility of applying mathematical knowledge to the facts of nature they had formed no conception whatever. Their philosophy was a tangle of barren controversies reducible, for the most part, to verbal disputes. It bore no relation to the facts of real life. It held out no hope of raising the Catholic Church to the position of intellectual domination needed for establishing her authority over the Asiatic world, from which dangers were looming of appalling magnitude…
The mind of Roger Bacon was strangely compounded of almost prophetic gleams of the future course of science, and the best principles of the inductive philosophy, with a more than usual credulity in the superstitions of his own time. Some have deemed him overrated by the nationality of the English; but, if we may have sometimes given him credit for discoveries to which he has only borne testimony, there can be no doubt of the originality of his genius.
(11) George Henry Lewes, Aristotle: A Chapter from the History of Science (1864)
Roger Bacon, a disciple of the Arabs, also insisted on the primary necessity of Mathematics, without which no other science can be known; yet by Mathematics it is clear that he meant something very different from what we mean, including under that head even dancing, singing, gesticulation, and performance on musical instruments….
Roger Bacon, a man of almost universal genius, and who wrote on almost every branch of science. He frequently quotes Alhazen on the subject of optics, and seems to have carefully studied his writings, as well as those of other Arabians, which were the fountains of natural knowledge in those days, and which had been introduced into Europe by means of the Moors in Spain. Notwithstanding the pains this great man took with the subject of optics, it does not appear that, with respect to theory, he made any considerable advance upon what Alhazen had done before him.
(12) Joseph Priestley, The History and Present State of Discoveries Relating to Vision, Light, and Colours (1772)
Great as Bacon was, he was far from being free from the mistakes and prejudices of those who went before him. Even some of the most wild and absurd opinions of the ancients have the sanction of his approbation and authority. He does not hesitate to assent to an opinion... that visual rays proceed from the eye; giving this reason for it, that everything in nature is qualified to discharge its proper functions by its own powers, in the same manner as the sun, and other celestial bodies. He acknowledges, however, that the presence of light, as well as several other circumstances, is necessary to vision…
In his Opus Majus he demonstrates, that if a transparent body, interposed between the eye and an object, be convex towards the eye, the object will appear magnified. This observation our author certainly had from Alhazen... this writer (Bacon) gives us figures, representing the progress of rays of light through his spherical segment, as well as endeavours to give reasons why objects are magnified... From the writings of Alhazen and these observations and experiments of Bacon together, it is not improbable that some monks gradually hit upon the construction of spectacles, to which Bacon's lesser segment, not withstanding his mistake concerning it, was a nearer approach than Alhazen's... Whoever they were that pursued the discoveries of Bacon, they probably observed, that a very small convex glass, when held at a greater distance from a book, would magnify the letters more than when it was placed close to them, in which position only Bacon seemed to have used it. In the next place, they might try whether two of these small segments of a sphere placed together, or a glass convex on both sides, would not magnify more than one of them. They would then find, that two of these glasses, one for each eye, would answer the purpose of reading better than one; and lastly they might find, that different degrees of convexity, suited different persons. It is certain that spectacles were well known in the 13th century, and not long before... It would certainly have been a great satisfaction to us to have been able to trace the actual steps in the progress of this most useful invention, without which most persons who have a taste for reading must have had the melancholy prospect of passing a very dull and joyless old age; and must have been deprived of the pleasure of entertaining themselves by conversing with the absent and the dead, when they were no longer capable of acting their part among the living. Telescopes and microscopes are to be numbered among the superfluities of life when compared to spectacles, which may now be ranked almost among the necessities of it; since the arts of reading and writing are almost universal.
(13) Bertrand Russell, History of Western Philosophy (1946)
Roger Bacon was not greatly admired in his own day, but in modern times has been praised far beyond his deserts. He was not so much a philosopher, in the narrow sense, as a man of universal learning with a passion for mathematics and science. Science, in his day, was mixed up with alchemy, and thought to be mixed up with black magic; Bacon was constantly getting into trouble through being suspected of heresy and magic…
He was encyclopaedic in his learning, but not systematic. Unlike most philosophers of the time, he valued experiment highly, and illustrated its importance by the theory of the rainbow. He wrote well on geography; Columbus read this part of his work, and was influenced by it. He was a good mathematician… Logic he thought a useless study; alchemy, on the other hand, he valued enough to write on it.
(14) Anthony Grayling, The History of Philosophy (2019)
Perhaps the least characteristic figure in the philosophy of the middle ages is Roger Bacon. His primary interest was ‘natural philosophy', which we now call ‘science', and he was an empiricist: he argued that ‘theories supplied by reason should be verified by sensory data, aided by instruments, and corroborated by trustworthy witnesses.' To some historians of ideas, therefore, he appears as an anomaly in his age, a modern before modern times, who would have been more at home with Galileo and Newton in the seventeenth century as a colleague in the rise of science. Others, however, argue that his interest in alchemy and astrology keep him firmly among the medieval, while others again point to the work of Robert Grosseteste and Albertus Magnus whose own scientific interests were in some respects similar to those of Bacon.
(15) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003)
It was Bacon's development of the principle of experimental science that makes him so important. For thousands of years before Bacon, and as far ahead as Newton's time, it was normal practice to accept the word of authorities rather than to observe anew, frame hypotheses, and test them using scientific principles. But Bacon, like the modern scientists who followed him, rejected this ‘natural philosophy'. He would not accept pure argument; everything should be subject to experiment.
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References
(1) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 14
(2) Jeremiah Hackett, Roger Bacon and the Sciences: Commemorative Essays (1997) page 10
(3) Elisabeth Leedham-Green, A Concise History of the University of Cambridge (1996) page 3
(4) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 17
(5) Roger Bacon, Opus Tertium (c. 1270)
(6) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 28
(7) Roger Bacon, Opus Tertium (c. 1270)
(8) George Molland, Roger Bacon : Oxford Dictionary of National Biography (September, 2004)
(9) Jean Gimpel, The Medieval Machine: The Industrial Revolution of the Middle Ages (1976) pages 194-5
(10) Roger Bacon, Opus Tertium (c. 1270)
(11) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 33
(12) Stephen J. Williams, Roger Bacon and the Secret of Secrets (1997) pages 365-374
(13) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) pages 36-37
(14) George Henry Lewes, Aristotle: A Chapter from the History of Science (1864) page 186
(15) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 132
(16) Roger Bacon, Opus Tertium (c. 1270)
(17) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 187
(18) Roger Bacon, Opus Majus (c. 1267)
(19) Roger Bacon, Opus Tertium (c. 1270)
(20) Anthony Grayling, The History of Philosophy (2019) page 158
(21) John A. Bagley, George Cayley : Oxford Dictionary of National Biography (September, 2004)
(22) Roger Bacon, On the Marvellous Power of Art and Nature (c. 1260)
(23) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 40
(24) Roger Bacon, On the Marvellous Power of Art and Nature (c. 1260)
(25) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 40
(26) Bertrand Russell, History of Western Philosophy (1946) page 445
(27) George Molland, Roger Bacon : Oxford Dictionary of National Biography (September, 2004)
(28) J. H. Bridges, The Opus Majus of Roger Bacon (1900) page viii
(29) George Henry Lewes, Aristotle: A Chapter from the History of Science (1864) page 186
(30) Roger Bacon, Opus Majus (c. 1267)
(31) Joseph Priestley, The History and Present State of Discoveries Relating to Vision, Light, and Colours (1772) page 24
(32) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 45
(33) Roger Bacon, Opus Majus (c. 1267)
(34) Bertrand Russell, History of Western Philosophy (1946) page 445
(35) Roger Bacon, Opus Majus (c. 1267)
(36) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 46
(37) Roger Bacon, Opus Majus (c. 1267)
(38) Tonio Andrade, The Gunpowder Age: China, Military Innovation, and the Rise of the West in World History (2016) page 31
(39) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 47
(40) Roger Bacon, Opus Majus (c. 1267)
(41) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) pages 199-200
(42) Roger Bacon, Opus Tertium (c. 1270)
(43) Roger Bacon, Opus Majus (c. 1267)
(44) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 104
(45) Roger Bacon, Opus Majus (c. 1267)
(46) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 106
(47) Anthony Grayling, The History of Philosophy (2019) page 159
(48) Roger Bacon, Opus Majus (c. 1267)
(49) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) pages 83-85
(50) Roger Bacon, Opus Majus (c. 1267)
(51) Anthony Grayling, The History of Philosophy (2019) page 158
(52) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) pages 85-87
(53) David Ewing Duncan, The Calendar: The 5000-year Struggle to Align the Clock and the Heavens (2011) pages 1-2
(54) Brian Clegg, The First Scientist: A Life of Roger Bacon (2003) page 127
(55) Evalyn Westacott, Roger Bacon In Life And Legend (1953) page 43
