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Article abstract: Bacon was a pioneer in the development of the scientific experimental method, and he advocated educational reform based on secular, scientific disciplines.

Early Life

Roger Bacon was born into a family of minor nobility sometime around the year 1220 in Ilchester, Somerset, England. Although very little is known concerning his life prior to 1239, he was trained in his youth in the classics and in the quadrivium (arithmetic, geometry, astronomy, and music). He studied the liberal arts at Oxford University and received his baccalaureate from either Oxford or the University of Paris around 1239. Soon thereafter, he received a master of arts from Paris and began his teaching career there as a regent master on the arts faculty.

During Bacon’s early professional years, he lectured on Aristotelian and pseudo-Aristotelian treatises—especially the Secretum secretorum (fourth century b.c.e.), a long letter of advice on kingship and practical affairs supposedly written by Aristotle to Alexander the Great—but he exhibited no indication of his later preoccupation with science. As an eclectic thinker during this period from 1239 to 1247, Bacon blended his Aristotelian ideas with certain Neoplatonist elements derived from many different sources. Nevertheless, he was one of the first Parisian masters to lecture on the forbidden books of Aristotle soon after the Church lifted the ban. There, he wrote his early scholastic works and commentaries on grammar, dialectics, physics, metaphysics, and astronomy. He also popularized the ideas of Avicenna, al-Ghazali, and Averroes, thus integrating Arabic thought with that of the West. Again, his eclecticism led him to criticize the Moslem savants on many issues, especially when they espoused concepts that he considered to be anti-Christian or antiscriptural.

About 1247, a major change occurred in Bacon’s intellectual development. Abandoning his teaching position in Paris to return to Oxford, he devoted all of his time, and large sums of money raised mainly from family members, to experimental research, to acquiring certain “secret” books, to constructing scientific instruments and tables, to training assistants, and to conferring with scholars of like mind. These activities marked a definite departure from the usual routine practiced by his colleagues. Through these endeavors he became immensely impressed with the benefits that science could bestow upon religion—a “universal” science that would include all the secrets of nature.

This change probably was caused by the Oxford environment and the influence exerted there by Robert Grosseteste (whom Bacon may never have met personally), a leader in introducing Greek learning to the West and an early advocate of the experimental method. Bacon was also impressed by Adam Marsh, Grosseteste’s most famous associate, and by Thomas Wallensis, the bishop of St. David’s.

From 1247 to 1257, Bacon devoted himself to the study of languages, optics, alchemy, astronomy, and mathematics. He campaigned against hearsay evidence, denounced rational, Platonist deductions, and extolled experimentation so relentlessly that he began to anger the more traditional scholars. Although his role as an experimenter may be exaggerated historically and his originality may not have produced significant scientific or technological breakthroughs, he did operate a quasi-laboratory for alchemical experiments and did carry out systematic observations with lenses and mirrors. Also important was his work on the nature of light (reflection, refraction, and spherical aberration) and on the rainbow. Of lesser significance were his ideas on flight, gunpowder, mechanically propelled land vehicles and seacraft, and eclipses of the sun.

Life’s Work

About 1252, Bacon joined the Franciscan Order (soon after Grosseteste had bequeathed his library to them), but from the beginning he appears to have been unhappy. He had difficulty acquiring scientific equipment, he abhorred his colleagues’ disinterest in his work, and he resented the preference shown by his superiors to the more orthodox teachers on the faculty. Within several years, he became embittered and began to level criticisms (often unjust) at some of the best minds of his age. Yet for a time, he was permitted to engage in scientific speculation and observation without interference.

In 1257, he was transferred to the Frairs Minor convent at Paris, possibly because of the aforementioned personal difficulties but certainly not for his scientific endeavors. His feverish activity, amazing credulity, supposed superstition, and vocal contempt for those who opposed him obviously irritated the established English members. He would always feel suspicion, and his increasing physical infirmities and lack of support would plague him for the remainder of his life.

From 1257 to 1266, Bacon taught mathematics, perspective, and philosophy at the Franciscan studium. Eventually, the Order’s hostility to his ideas forced him to appeal to Pope Clement IV (Cardinal Guy de Foulques), whom he may have known when the latter was in the service of the Capetian kings. In correspondence of 1266, the pope referred to letters that he received from Bacon that described various aspects of the natural world, mathematics, languages, physics, and astrology. Bacon envisioned the production of an encyclopedia—a massive compendium of all verifiable knowledge—to be put to the ultimate service of theology. He stated that such a scientific work would be of great value in confirming Christian faith, in maintaining the welfare of the Church and the universities, and in sponsoring educational reform. Desiring a fuller understanding of this project, the pope ordered Bacon to send him detailed information and to proceed in total secrecy because of the Franciscan rule against unauthorized writing.

In obedience to the pope’s command, Bacon set to work in 1266 and in a remarkably short period of approximately eighteen months produced the Opus majus (1267), the Opus minus (1267), and the Opus tertium (1267-1268). The Opus majus contains all of his basic ideas for educational reform based upon the supremacy of the sciences. The second and third works were largely synopses. The death of the pope in November of 1268 dealt a crushing blow to Bacon’s chances of an official reception and extinguished his lifelong dream. The pope may not have read any of them.

Bacon divided the Opus majus into eight sections. The first delineated four barriers to truth: submission to untrustworthy authority, influence of custom, popular prejudice, and concealment of ignorance within philosophical jargon. The second showed the close relationship between philosophy and theology since they were both revealed by God to man. In section 3, Bacon stressed that all true scholars must be proficient in Hebrew, Greek, and Arabic if they desired to do meaningful research. Section 4 was a defense of the intimate correlation of the sciences with theology. Section 5 contained his theories of vision and optical science. In the sixth section—the most important—Bacon formulated his notion of experimental science. To him, experimentation certified the conclusions of deductive or mathematical reasoning, added new information to existing knowledge, and served to increase technological proficiency in both war and peace. The last two sections dealt with philosophical and political science questions that would be examined in greater depth by another Parisian master in the early years of the next century—marsiglius of Padua in his Defensor pacis (1324).

Soon after the completion of these masterpieces, Bacon returned to England. He did little significant writing thereafter, save for some nonscientific works on grammar and philosophy. In 1272, he issued a highly polemical pamphlet directed against his opponents, and this produced more trouble for him within his order. A later source (the Chronicle of the Twenty-four Generals of 1370) reveals that he was imprisoned sometime between 1277 and 1279 for “suspected novelties” by the general of his order, Jerome of Ascoli (later Pope Nicholas IV). It is difficult, however, to determine what these “novelties” were since his ideas did not differ greatly from those of his contemporaries except in overall emphasis. The imprisonment, if indeed it were a true incarceration, was undoubtedly for personal reasons rather than for his scientific work. In any case, he was freed shortly before his death.


Roger Bacon was instrumental in laying the early foundation of modern scientific thinking. He was keenly aware of the interrelatedness of all the separate sciences and of the contributions that science makes to the understanding of reality. He explained the role of the experimental method in confirming or refuting speculative hypotheses. He insisted on the practical value of scientific speculation and believed in the importance of an ethical superstructure that would act as a system of checks and balances upon the discovery of new knowledge.

During his many years of scientific research, Bacon endeavored to discover all that could be known, but it seems clear that although he did some experimental work himself, his real claim to fame rests on his achievements as a scientific thinker and synthesist of other scholars’ work. He has been credited, sometimes erroneously, with the introduction of gunpowder, eyeglasses, the telescope, and other technological developments. His works certainly describe these things and he understood the principles upon which they were based, but he never claimed credit for their invention. His experimental method may not be compatible with modern scientific method, but given the limitations of his time, his formulation was valid. In his conception of the immediate practical use of science, he was a harbinger of later work that led to the age of science in the early modern world. Roger Bacon did not create modern science; he inspired it.


Crombie, A. C. Medieval and Early Modern Science. 2 vols. Garden City, N.Y.: Doubleday Anchor Books, 1959. Extensive bibliographic coverage with detailed analyses of Bacon’s contributions to calendar reform, scientific classifications, education, geography, geology, ophthalmology, optics, and physics.

Crombie, A. C. Robert Grosseteste and the Origins of Experimental Science, 1100-1700. Oxford: Clarendon Press, 1953. A detailed examination of experimentation in the thirteenth century and its relationship to modern scientific method.

Easton, Stewart C. Roger Bacon and His Search for a Universal Science. New York: Columbia University Press, 1952. Besides being an excellent bibliography of primary and secondary sources, Easton’s account is valuable for its emphasis on Bacon’s early life, educational experiences, Paris professorship, scientific contributions, religious conflicts, and impact on science and education.

Leff, Gordon. Paris and Oxford Universities in the Thirteenth and Fourteenth Centuries. New York: John Wiley and Sons, 1968. Bacon is cast within an institutional context that emphasizes university regulations, curricular requirements, teaching privileges, and intellectual developments. Special emphasis is placed on Aristotelianism and its influence on later medieval education.

Steele, R. “Roger Bacon and the State of Science in the Thirteenth Century.” In Studies in the History and Method of Science, edited by Charles Singer. Oxford: Clarendon Press, 1921. The best early attempt to show the continuity of Bacon’s scientific thought.

Thorndike, Lynn. A History of Magic and Experimental Science. 6 vols. New York: Macmillan, 1923-1941. Volume 2 contains many valuable discussions of Bacon’s contributions to science; especially important for information on thirteenth century scientists and for criticism of those historians who overestimated Bacon’s uniqueness. One of the seminal studies on the subject, based upon earlier Baconian publications by Thorndike in the Philosophical Review of 1914 and the American Historical Review of 1916.

Westacott, E. Roger Bacon in Life and Legend. New York: Philosophical Library, 1953. Among the more important topics covered are Bacon’s principal works (in synopses, notably the Opus majus), his role as a medieval philosopher and scientist, and his creativity in the secular disciplines.