In theearly modern era, he was regarded as awizard and particularly famed for the story of hismechanical ornecromanticbrazen head. He is credited as one of the earliest European advocates of the modernscientific method, along with his teacherRobert Grosseteste. Bacon applied the empirical method ofIbn al-Haytham (Alhazen) to observations in texts attributed toAristotle. Bacon discovered the importance of empirical testing when the results he obtained were different from those that would have been predicted by Aristotle.[4][5]
His linguistic work has been heralded for its early exposition of auniversal grammar, and 21st-century re-evaluations emphasise that Bacon was essentially a medieval thinker, with much of his "experimental" knowledge obtained from books in thescholastic tradition.[6] He was, however, partially responsible for a revision of themedieval university curriculum, which saw the addition ofoptics to the traditionalquadrivium.[7]
Roger Bacon was born inIlchester inSomerset,England, in the early 13th century. His birth is sometimes narrowed down to 1210,[8] 1213 or 1214,[9] 1215[10] or 1220.[11] The only source for his birth date is a statement from his 1267Opus Tertium that "forty years have passed since I first learned theAlphabetum".[12] The latest dates assume this referred to thealphabet itself, but elsewhere in theOpus Tertium it is clear that Bacon uses the term to refer to rudimentary studies, thetrivium orquadrivium that formed themedieval curriculum.[13] His family appears to have been well off.[14]
Bacon studied atOxford.[n 1] WhileRobert Grosseteste had probably left shortly before Bacon's arrival, his work and legacy almost certainly influenced the young scholar[8] and it is possible Bacon subsequently visited him andWilliam of Sherwood inLincoln.[16] Bacon became aMaster at Oxford, lecturing onAristotle. There is no evidence he was ever awarded a doctorate. (The titleDoctor Mirabilis was a posthumousscholastic accolade.) A caustic cleric named Roger Bacon is recorded speaking before the king at Oxford in 1233.[17]
A diorama of Bacon presenting one of his works to the chancellors ofParis University
A 19th-century engraving of Bacon observing the stars atOxford
As a private scholar, his whereabouts for the next decade are uncertain[22] but he was likely in Oxfordc. 1248–1251, where he metAdam Marsh, and in Paris in 1251.[19] He seems to have studied most of the knownGreek andArabic works onoptics[20] (then known as "perspective",perspectiva). A passage in theOpus Tertium states that at some point he took a two-year break from his studies.[12]
In 1256 or 1257, he became afriar in theFranciscan Order in either Paris or Oxford, following the example of scholarly English Franciscans such asGrosseteste andMarsh.[19] After 1260, Bacon's activities were restricted by a statute prohibiting the friars of his order from publishing books or pamphlets without prior approval.[24] He was likely kept at constant menial tasks to limit his time for contemplation[25] and came to view his treatment as an enforced absence from scholarly life.[19]
By the mid-1260s, he was undertaking a search for patrons who could secure permission and funding for his return to Oxford.[25] For a time, Bacon was finally able to get around his superiors' interference through his acquaintance withGuy de Foulques,bishop of Narbonne,cardinal of Sabina, and thepapal legate who negotiated between England's royal and baronial factions.[23]
In 1263 or 1264, a message garbled by Bacon's messenger, Raymond of Laon, led Guy to believe that Bacon had already completed a summary of the sciences. In fact, he had no money to research, let alone copy, such a work and attempts to secure financing from his family were thwarted by the Second Barons' War. However, in 1265, Guy was summoned to a conclave atPerugia thatelected himPope Clement IV.[26] William Benecor, who had previously been the courier betweenHenry III and the pope, now carried the correspondence between Bacon and Clement.[26] Clement's reply of 22 June 1266 commissioned "writings and remedies for current conditions", instructing Bacon not to violate any standing "prohibitions" of his order but to carry out his task in utmost secrecy.[26]
While faculties of the time were largely limited to addressing disputes on the known texts of Aristotle, Clement's patronage permitted Bacon to engage in a wide-ranging consideration of the state of knowledge in his era.[19] In 1267 or '68, Bacon sent the Pope hisOpus Majus, which presented his views on how to incorporateAristotelian logic andscience into a new theology, supporting Grosseteste's text-based approach against the "sentence method" then fashionable.[19]
Bacon also sent hisOpus Minus,De Multiplicatione Specierum,[27]De Speculis Comburentibus, an optical lens,[19] and possibly other works onalchemy andastrology.[27][n 3] The entire process has been called "one of the most remarkable single efforts of literary productivity", with Bacon composing referenced works of around a million words in about a year.[28]
Pope Clement died in 1268 and Bacon lost his protector. TheCondemnations of 1277 banned the teaching of certain philosophical doctrines, including deterministic astrology. Some time within the next two years, Bacon was apparently imprisoned or placed underhouse arrest. This was traditionally ascribed toFranciscan Minister GeneralJerome of Ascoli, probably acting on behalf of the many clergy, monks, and educators attacked by Bacon's 1271Compendium Studii Philosophiae.[1]
Modern scholarship, however, notes that the first reference to Bacon's "imprisonment" dates from eighty years after his death on the charge of unspecified "suspected novelties"[29][30] and finds it less than credible.[31] Contemporary scholars who do accept Bacon's imprisonment typically associate it with Bacon's "attraction to contemporary prophesies",[32] his sympathies for "the radical 'poverty' wing of the Franciscans",[31] interest in certainastrological doctrines,[33] or generally combative personality[30] rather than from "any scientific novelties which he may have proposed".[31]
Sometime after 1278, Bacon returned to the Franciscan House at Oxford, where he continued his studies[34] and is presumed to have spent most of the remainder of his life. His last dateable writing—theCompendium Studii Theologiae—was completed in 1292.[1] He seems to have died shortly afterwards and been buried at Oxford.[2][35]
A manuscript illustration of Bacon presenting one of his works to the chancellor of theUniversity of Paris
Medieval European philosophy often relied onappeals to the authority ofChurch Fathers such asSt Augustine, and on works byPlato andAristotle only known at second hand or through Latin translations. By the 13th century, new works and better versions – inArabic or in new Latin translations from the Arabic – began to trickle north fromMuslim Spain. In Roger Bacon's writings, he upholds Aristotle's calls for the collection of facts before deducing scientific truths, against the practices of his contemporaries, arguing that "thence cometh quiet to the mind".
Bacon also called for reform with regard totheology. He argued that, rather than training to debate minor philosophical distinctions, theologians should focus their attention primarily on theBible itself, learning the languages of its original sources thoroughly. He was fluent in several of these languages and was able to note and bemoan several corruptions of scripture, and of the works of the Greek philosophers that had been mistranslated or misinterpreted by scholars working in Latin. He also argued for the education of theologians in science ("natural philosophy") and its addition to themedieval curriculum.
Bacon's 1267Greater Work, theOpus Majus,[n 4] contains treatments ofmathematics,optics,alchemy, andastronomy, including theories on the positions and sizes of thecelestial bodies. It is divided into seven sections: "The Four General Causes of Human Ignorance" (Causae Erroris),[36] "The Affinity of Philosophy with Theology" (Philosophiae cum Theologia Affinitas),[37] "On the Usefulness of Grammar" (De Utilitate Grammaticae),[38] "The Usefulness of Mathematics in Physics" (Mathematicae in Physicis Utilitas),[39] "On the Science of Perspective" (De Scientia Perspectivae),[40] "On Experimental Knowledge" (De Scientia Experimentali),[41] and "A Philosophy of Morality" (Moralis Philosophia).[42]
It was not intended as a complete work but as a "persuasive preamble" (persuasio praeambula), an enormous proposal for a reform of themedieval university curriculum and the establishment of a kind of library or encyclopedia, bringing in experts to compose a collection of definitive texts on these subjects.[43] The new subjects were to be "perspective" (i.e.,optics), "astronomy" (inclusive ofastronomy proper,astrology, and thegeography necessary to use them), "weights" (likely some treatment ofmechanics but this section of theOpus Majus has been lost),alchemy,agriculture (inclusive ofbotany andzoology),medicine, and "experimental science", aphilosophy of science that would guide the others.[43] The section on geography was allegedly originally ornamented with amap based on ancient and Arabic computations of longitude and latitude, but has since been lost.[44] His (mistaken) arguments supporting the idea that dry land formed the larger proportion of the globe were apparently similar to those which later guidedColumbus.[44]
In this work Bacon criticises his contemporariesAlexander of Hales andAlbertus Magnus, who were held in high repute despite having only acquired their knowledge ofAristotle at second hand during their preaching careers.[45][46] Albert was received at Paris as an authority equal to Aristotle,Avicenna andAverroes,[47] a situation Bacon decried: "never in the world [had] such monstrosity occurred before."[48]
In Part I of theOpus Majus Bacon recognises some philosophers as theSapientes, or gifted few, and saw their knowledge in philosophy and theology as superior to thevulgus philosophantium, or common herd of philosophers. He held Islamic thinkers between 1210 and 1265 in especially high regard calling them "both philosophers and sacred writers" and defended the integration of philosophy from apostate philosopher of the Islamic world into Christian learning.[49]
It had become apparent thatEudoxus andSosigenes's assumption of a year of 365¼ days was, over the course of centuries, too inexact. Bacon charged that this meant thecomputation of Easter had shifted forward by 9 days since theFirst Council of Nicaea in 325.[50] His proposal to drop one day every 125 years[39][51] and to cease the observance of fixedequinoxes andsolstices[50] was not acted upon following the death ofPope Clement IV in 1268. The eventualGregorian calendar drops one day from the first three centuries in each set of 400 years.
"Roger Bacon discovers gunpowder", "wherebyGuy Fawkes was made possible",[54] an image fromBill Nye's Comic History of England[55]
A passage in theOpus Majus and another in theOpus Tertium are usually taken as the first European descriptions of a mixture containing the essential ingredients ofgunpowder.Partington and others have come to the conclusion that Bacon most likely witnessed at least one demonstration ofChinesefirecrackers, possibly obtained by Franciscans—including Bacon's friendWilliam of Rubruck—who visited theMongol Empire during this period.[56][n 5] The most telling passage reads:
We have an example of these things (that act on the senses) in [the sound and fire of] that children's toy which is made in many [diverse] parts of the world; i.e. a device no bigger than one's thumb. From the violence of that salt called saltpetre [together with sulphur and willow charcoal, combined into a powder] so horrible a sound is made by the bursting of a thing so small, no more than a bit of parchment [containing it], that we find [the ear assaulted by a noise] exceeding the roar of strong thunder, and a flash brighter than the most brilliant lightning.[56]
At the beginning of the 20th century,Henry William Lovett Hime of theRoyal Artillery published the theory that Bacon'sEpistola contained acryptogram giving a recipe for the gunpowder he witnessed.[58] The theory was criticised byThorndike in a 1915 letter toScience[59] and several books, a position joined byMuir,[60]John Maxson Stillman,[60]Steele,[61] andSarton.[62]Needham et al. concurred with these earlier critics that the additional passage did not originate with Bacon[56] and further showed that the proportions supposedly deciphered (a 7:5:5 ratio ofsaltpetre tocharcoal tosulphur) as not even useful for firecrackers, burning slowly with a great deal of smoke and failing to ignite inside a gun barrel.[63] The ~41%nitrate content is too low to have explosive properties.[64]
Bacon attributed theSecret of Secrets (Secretum Secretorum), the Islamic "Mirror of Princes" (Arabic:Sirr al-ʿasrar), toAristotle, thinking that he had composed it forAlexander the Great. Bacon produced an edition ofPhilip of Tripoli's Latin translation, complete with his own introduction and notes; and his writings of the 1260s and 1270s cite it far more than his contemporaries did. This ledEaston[66] and others, includingRobert Steele,[67] to argue that the text spurred Bacon's own transformation into an experimentalist. (Bacon never described such a decisive impact himself.)[67] The dating of Bacon's edition of theSecret of Secrets is a key piece of evidence in the debate, with those arguing for a greater impact giving it an earlier date;[67] but it certainly influenced the elder Bacon's conception of the political aspects of his work in the sciences.[19]
A 19th-century etching of Bacon conducting an alchemical experiment
Bacon has been credited with a number ofalchemical texts.[68]
TheLetter on the Secret Workings of Art and Nature and on the Vanity of Magic (Epistola de Secretis Operibus Artis et Naturae et de Nullitate Magiae),[69] also known asOn the Wonderful Powers of Art and Nature (De Mirabili Potestate Artis et Naturae), a likely-forged letter to an unknown "William of Paris," dismisses practices such asnecromancy[70] but contains most of the alchemical formulae attributed to Bacon,[68] including one for aphilosopher's stone[71] and another possibly forgunpowder.[56] It also includes several passages abouthypothetical flying machines andsubmarines, attributing their first use toAlexander the Great.[72]On the Vanity of Magic orThe Nullity of Magic is adebunking of esoteric claims in Bacon's time, showing that they could be explained by natural phenomena.[73]
He wrote on the medicine ofGalen, referring to the translations ofAvicenna. He believed that the medicine of Galen belonged to an ancient tradition passed throughChaldeans,Greeks andArabs.[74] Although he provided a negative image ofHermes Trismegistus, his work was influenced by theRenaissance Hermetic thought[dubious –discuss][clarification needed].[75] Bacon's endorsement of Hermetic philosophy is evident, as his citations of the alchemical literature known as the Secretum Secretorum made several appearances in the Opus Majus. The Secretum Secretorum contains knowledge about the HermeticEmerald Tablet, which was an integral component of alchemy, thus proving that Bacon's version of alchemy was much less secular, and much more spiritual than once interpreted. The importance of Hermetic philosophy in Bacon's work is also evident through his citations of classic Hermetic literature such as the Corpus Hermeticum. Bacon's citation of the Corpus Hermeticum, which consists of a dialogue between Hermes and the pagan deityAsclepius, proves that Bacon's ideas were much more in line with the spiritual aspects of alchemy rather than the scientific aspects. However, this is somewhat paradoxical as what Bacon was specifically trying to prove in the Opus Majus and subsequent works, was that spirituality and science were the same entity. Bacon believed that by using science, certain aspects of spirituality such as the attainment of "Sapientia" or "Divine Wisdom" could be logically explained using tangible evidence. Bacon's Opus Majus was first and foremost, a compendium of sciences which he believed would facilitate the first step towards "Sapientia". Bacon placed considerable emphasis on alchemy and even went so far as to state that alchemy was the most important science. The reason why Bacon kept the topic of alchemy vague for the most part, is due to the need for secrecy about esoteric topics in England at the time as well as his dedication to remaining in line with the alchemical tradition of speaking in symbols and metaphors.[76]
Bacon's early linguistic and logical works are theOverview of Grammar (Summa Grammatica),Summa de Sophismatibus et Distinctionibus, and theSummulae Dialectices orSummulae super Totam Logicam.[19] These are mature but essentially conventional presentations of Oxford and Paris's terminist and pre-modist logic and grammar.[19] His later work in linguistics is much more idiosyncratic, using terminology and addressing questions unique in his era.[77]
In hisGreek andHebrew Grammars (Grammatica Graeca andHebraica), in his work "On the Usefulness of Grammar" (Book III of theOpus Majus), and in hisCompendium of the Study of Philosophy,[77] Bacon stresses the need for scholars to know several languages.[78] Europe's vernacular languages are not ignored—he considers them useful for practical purposes such astrade,proselytism, andadministration—but Bacon is mostly interested in his era'slanguages of science and religion:Arabic,Greek,Hebrew andLatin.[78]
Bacon is less interested in a full practical mastery of the other languages than on a theoretical understanding of their grammatical rules, ensuring that a Latin reader will not misunderstand passages'original meaning.[78] For this reason, his treatments of Greek and Hebrew grammar are not isolated works on their topic[78] but contrastive grammars treating the aspects which influenced Latin or which were required for properly understanding Latin texts.[79] He pointedly states, "I want to describe Greek grammar for the benefit of Latin speakers".[80][n 6] It is likely only this limited sense which was intended by Bacon's boast that hecould teach an interested pupil a new language within three days.[79][n 7]
Passages in theOverview and the Greek grammar have been taken as an early exposition of auniversal grammar underlying allhumanlanguages.[81] The Greek grammar contains the tersest and most famous exposition:[81]
Grammar is one and the same in all languages, substantially, though it may vary, accidentally, in each of them.[84][n 8]
However, Bacon's lack of interest in studying a literalgrammar underlying the languages known to him and his numerous works on linguistics and comparative linguistics has promptedHovdhaugen to question the usual literal translation of Bacon'sgrammatica in such passages.[85] She notes the ambiguity in the Latin term, which could refer variously to the structure of language, to its description, and to the science underlying such descriptions: i.e.,linguistics.[85]
A portrait of Roger Bacon from a 15th-century edition ofDe Retardatione[86]The first page of the letter from Bacon toClement IV introducing hisOpus Tertium[87]
Bacon states that hisLesser Work (Opus Minus) andThird Work (Opus Tertium) were originally intended as summaries of theOpus Majus in case it was lost in transit.[43]Easton's review of the texts suggests that they became separate works over the course of the laborious process of creating afair copy of theOpus Majus, whose half-million words were copied by hand and apparently greatly revised at least once.[28]
Other works by Bacon include his "Tract on the Multiplication of Species" (Tractatus de Multiplicatione Specierum),[88] "On Burning Lenses" (De Speculis Comburentibus), theCommunia Naturalium andMathematica, the "Compendium of the Study of Philosophy" and "of Theology" (Compendium Studii Philosophiae andTheologiae), and hisComputus.[19] The "Compendium of the Study of Theology", presumably written in the last years of his life, was an anticlimax: adding nothing new, it is principally devoted to the concerns of the 1260s.
The Mirror of Alchimy (Speculum Alchemiae), a short treatise on the origin and composition of metals, is traditionally credited to Bacon.[89] It espouses the Arabian theory ofmercury andsulphur forming the other metals, with vague allusions totransmutation.Stillman opined that "there is nothing in it that is characteristic of Roger Bacon's style or ideas, nor that distinguishes it from many unimportant alchemical lucubrations of anonymous writers of the thirteenth to the sixteenth centuries", andMuir andLippmann also considered it apseudepigraph.[90]
A woodcut fromRobert Greene'splay displaying thebrazen head pronouncing "Time is. Time was. Time is past.""Friar Bacon's Study" inOxford. By the late 18th century this study onFolly Bridge had become a place of pilgrimage for scientists, but the building was pulled down in 1779 to allow for road widening.[98]The Westgate plaque at Oxford
By theearly modern period, the English considered him the epitome of a wise and subtle possessor offorbidden knowledge, aFaust-like magician who had tricked thedevil and so was able to go toheaven. Of these legends, one of the most prominent was that he created atalking brazen head which could answer any question. The story appears in the anonymous 16th-century account ofThe Famous Historie of Fryer Bacon,[n 9] in which Bacon speaks with a demon but causes the head to speak by "the continuall fume of the six hottest Simples",[101] testing his theory that speech is caused by "an effusion of vapors".[102]
Around 1589,Robert Greene adapted the story for the stage asThe Honorable Historie of Frier Bacon and Frier Bongay,[103][104][105] one of the most successfulElizabethan comedies.[104] As late as the 1640s,Thomas Browne was still complaining that "Every ear is filled with the story of Frier Bacon, that made a brazen head to speak these words,Time is".[106] Greene's Bacon spent seven years creating a brass head that would speak "strange and uncouth aphorisms"[107] to enable him to encircleBritain with a wall of brass that would make it impossible to conquer.
Unlike his source material, Greene does not cause his head to operate by natural forces but by "nigromantic charms" and "the enchanting forces of thedevil":[108] i.e., by entrapping adead spirit[102] orhobgoblin.[109] Bacon collapses, exhausted, just before his device comes to life and announces "Time is", "Time was", and "Time is Past"[110] before being destroyed in spectacular fashion: thestage direction instructs that "a lightening flasheth forth, and a hand appears that breaketh down the Head with a hammer".[111]
Anecromantic head was ascribed toPope Sylvester II as early as the 1120s,[112][n 10] butBrowne considered the legend to be a misunderstanding of a passage inPeter the Good'sc. 1335Precious Pearl where the negligent alchemist misses the birth of his creation and loses it forever.[106] The story may also preserve the work by Bacon and his contemporaries to construct clockworkarmillary spheres.[115] Bacon had praised a "self-activated working model of the heavens" as "the greatest of all things which have been devised".[116]
As early as the 16th century,natural philosophers such asBruno,Dee[117] andFrancis Bacon[7] were attempting to rehabilitate Bacon's reputation and to portray him as a scientific pioneer who had avoided the petty bickering of his contemporaries to attempt a rational understanding of nature. By the 19th century, commenters followingWhewell[118][7] considered that "Bacon ... was not appreciated in his age because he was so completely in advance of it; he is a 16th- or 17th-century philosopher, whose lot has been by some accident cast in the 13th century".[14] His assertions in theOpus Majus that "theories supplied by reason should be verified by sensory data, aided by instruments, and corroborated by trustworthy witnesses"[119] were (and still are) considered "one of the first important formulations of thescientific method on record".[73]
This idea that Bacon was a modern experimental scientist reflected two views of the period: that the principal form of scientific activity is experimentation and that 13th-century Europe still represented the "Dark Ages".[120] This view, which is still reflected in some 21st-centurypopular science books,[123] portrays Bacon as an advocate of modern experimental science who emerged as a solitary genius in an age hostile to his ideas.[124] Based on Bacon'sapocrypha, he is also portrayed as a visionary who predicted the invention of thesubmarine,aircraft, andautomobile.[125] Consistent with this view of Bacon as a man ahead of his time,H. G. Wells'sOutline of History attributes this prescient passage to him:
Machines for navigating are possible without rowers, so that great ships suited to river or ocean, guided by one man, may be borne with greater speed than if they were full of men. Likewise, cars may be made so that without a draught animal they may be movedcum impetu inaestimabili, as we deem the scythed chariots to have been from which antiquity fought. And flying machines are possible, so that a man may sit in the middle turning some device by which artificial wings may beat the air in the manner of a flying bird.[126]
However, in the course of the 20th century,Husserl,Heidegger and others emphasised the importance to the modern science ofCartesian andGalilean projections ofmathematics over sensory perceptions of nature; Heidegger, in particular, noted the lack of such an understanding in Bacon's works.[7] AlthoughCrombie,[127]Kuhn[128] andSchramm [de][129] continued to argue for Bacon's importance to the development of "qualitative" areas of modern science,[7]Duhem,[130]Thorndike,[131][132]Carton[133] andKoyré[134] emphasised the essentially medieval nature of Bacon'sscientia experimentalis.[133][135]
Research also established that Bacon was not as isolated—and probably not as persecuted—as was once thought. Many medieval sources of and influences on Bacon's scientific activity have been identified.[136] In particular, Bacon often mentioned his debt to the work ofRobert Grosseteste:[137] his work onoptics and thecalendar followed Grosseteste's lead,[138] as did his idea thatinductively-derived conclusions should be submitted for verification through experimental testing.[139]
Bacon noted ofWilliam of Sherwood that "nobody was greater in philosophy than he";[140][141] praisedPeter of Maricourt (the author of "A Letter on Magnetism")[142] andJohn of London as "perfect" mathematicians;Campanus of Novara (the author of works on astronomy, astrology, and the calendar) and a Master Nicholas as "good";[143] and acknowledged the influence ofAdam Marsh and lesser figures. He was clearly not an isolated genius.[137] The medieval church was also not generally opposed to scientific investigation[144] andmedieval science was both varied and extensive.[n 11]
Bacon was not a modern, out of step with his age, or a harbinger of things to come, but a brilliant, combative, and somewhat eccentricschoolman of the thirteenth century, endeavoring to take advantage of the new learning just becoming available while remaining true to traditional notions... of the importance to be attached to philosophical knowledge".[147]
A recent review of the many visions of Bacon across the ages says contemporary scholarship still neglects one of the most important aspects of his life and thought: his commitment to the Franciscan order.
HisOpus majus was a plea for reform addressed to the supremespiritual head of the Christian faith, written against a background ofapocalyptic expectation and informed by the driving concerns of thefriars. It was designed to improve training formissionaries and to provide new skills to be employed in the defence of the Christian world against the enmity of non-Christians and of theAntichrist. It cannot usefully be read solely in the context of thehistory of science andphilosophy.[148]
With regard to religion's influence on Bacon's philosophy,Charles Sanders Peirce noted, "To Roger Bacon,... the schoolmen's conception of reasoning appeared only an obstacle to truth... [but] Of all kinds of experience, the best, he thought, was interior illumination, which teaches many things about Nature which the external senses could never discover, such as thetransubstantiation of bread."[149] Later scholars have therefore viewed him as a proto-protestant.[150]
InOxford lore, Bacon is credited as the namesake ofFolly Bridge for having been placed under house arrest nearby.[151] Although this is probably untrue,[152] it had formerly been known as "Friar Bacon's Bridge".[153] Bacon is also honoured at Oxford by a plaque affixed to the wall of the new Westgate shopping centre.[151]
^Bacon has been claimed as an alumnus by bothMerton andBrasenose, despite having attended before the establishment of the collegiate system.[15]
^Though probably granting it to a partisan of their own cause, rather than razing it to the ground as is sometimes reported.[23]
^It is still uncertain whether theOpus Tertium was sent with the others or kept for further revision and development.[19]
^In his works, Bacon also refers to it as his "primary writing" (scriptum principale).[26]
^"Europeans were prompted by all this to take a closer interest in happenings far to the east. Four years after the invasion of 1241, the pope sent an ambassador to the Great Khan's capital in Mongolia. Other travellers followed later, of whom the most interesting wasWilliam of Rubruck (or Ruysbroek). He returned in 1257, and in the following year there are reports of experiments with gunpowder and rockets at Cologne. Then a friend of William of Rubruck, Roger Bacon, gave the first account of gunpowder and its use in fireworks to be written in Europe. A form of gunpowder had been known in China since before AD 900, and as mentioned earlier... Much of this knowledge had reached the Islamic countries by then, and the saltpetre used in making gunpowder there was sometimes referred to, significantly, as 'Chinese snow'."[57]
^Latin:Cupiens igitur exponere gramaticam grecam ad vtilitatem latinorum.[80]
^It has been claimed that the copies of Bacon's grammars which have survived was not their final form, butHovdhaugen considers that—even if that were the case—the final form would have been similar in scope to the surviving texts and mostly focused on improving a Latinate reader's understanding of texts in translation.[79]
^Latin:...grammatica vna et eadem est secundum substanciam in omnibus linguis, licet accidentaliter varietur....[80]
^Although the manuscript was circulated in byc. 1555, it was not published until 1627.[99] It was republished in the mid-19th century.[100]
^Malmesbury even notes that "probably some may regard all this as a fiction, because the vulgar are used to undermine the fame of scholars, saying that the man who excels in any admirable science, holds converse with the devil"[113] but professes himself willing to believe the stories aboutSylvester because of the (spurious) accounts he had of the pope's "shameful end".[114]
^"If revolutionary rational thoughts were expressed in theAge of Reason, they were only made possible because of the long medieval tradition that established the use of reason as one of the most important of human activities."[145]
^Sarton (September 1928), "Review ofThe Cipher of Roger Bacon",Isis, vol. 11, No. 1, The University of Chicago Press, The History of Science Society, pp. 141–145,doi:10.1086/346365,JSTOR224770
Bacon, Roger; et al. (1926),Steele, Robert (ed.),Compotus,Opera Hactenus Inedita Rogeri Baconi, No. VI (in Latin and English), Oxford: Humphrey Milford for the Clarendon Press
Bacon, Roger (1928), Delorme, Ferdinand M.; et al. (eds.),Questiones Supra Libros Quartuor Physicorum Aristotelis,Opera Hactenus Inedita Rogeri Baconi, No. VIII (in Latin and English), Oxford: Humphrey Milford for the Clarendon Press
Bacon, Roger (1935),Steele, Robert; et al. (eds.),Quaestiones supra Librum de Causis,Opera Hactenus Inedita Rogeri Baconi, No. XII (in Latin and English), Oxford: Clarendon Press
Bacon, Roger (1935), Delorme, Ferdinand M.; et al. (eds.),Questiones supra Libros Octo Physicorum Aristotelis,Opera Hactenus Inedita Rogeri Baconi, No. XIII (in Latin and English), Oxford: John Jonson for Clarendon Press
Bacon, Roger (1940),Steele, Robert (ed.),Communia Mathematica,Pt. I & II,Opera Hactenus Inedita Rogeri Baconi, No. XVI (in Latin and English), Oxford: John Jonson for the Clarendon Press
Bacon, Roger (1983),Lindberg, David C. (ed.),Roger Bacon's Philosophy of Nature: A Critical Edition, with English Translation, Introduction, and Notes, of "De Multiplicatione Specierum" and "De Speculis Comburentibus" (in Latin and English), Oxford: Clarendon Press
Bacon, Roger (2009), Maloney, Thomas S. (ed.),The Art and Science of Logic: A Translation of Roger Bacon'sSummulae Dialectices with Introduction and Notes,Mediaeval Sources in Translation, No. 47, Toronto: Pontifical Institute of Mediaeval Studies.
Bacon, Roger (2013), Maloney, Thomas S. (ed.),On Signs, Translated with Introduction and Notes,Mediaeval Sources in Translation, No. 54, Toronto: Pontifical Institute of Mediaeval Studies.
Ackerman, James S. (1978), "Leonardo's Eye",Journal of the Warburg & Courtauld Institutes, vol. 41.
Baldwin, James (1905),Thirty More Famous Stories Retold, Cincinnati: American Book Co..
Bartlett, Robert (2008) [b2006],The Natural and the Supernatural in the Middle Ages: The Wiles Lecture Given at the Queen's University of Belfast, 2006,Cambridge: Cambridge University Press,ISBN978-0-521-70255-3.
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