The Opus Majus is the most important work of Roger Bacon

Roger Bacon

Roger Bacon, O.F.M. , also known as Doctor Mirabilis , was an English philosopher and Franciscan friar who placed considerable emphasis on the study of nature through empirical methods...

. It was written in Medieval Latin

Medieval Latin

Medieval Latin was the form of Latin used in the Middle Ages, primarily as a medium of scholarly exchange and as the liturgical language of the medieval Roman Catholic Church, but also as a language of science, literature, law, and administration. Despite the clerical origin of many of its authors,...

, at the request of Pope Clement IV

Pope Clement IV

Pope Clement IV , born Gui Faucoi called in later life le Gros , was elected Pope February 5, 1265, in a conclave held at Perugia that took four months, while cardinals argued over whether to call in Charles of Anjou, the youngest brother of Louis IX of France...

, to explain the work that Bacon had undertaken. The 840-page treatise ranges over all aspects of natural science, from grammar and logic to mathematics, physics, and philosophy. Bacon sent his work to the Pope in 1267, accompanied by a letter of dedication which was found by F. A. Gasquet in the Vatican Library

Vatican Library

The Vatican Library is the library of the Holy See, currently located in Vatican City. It is one of the oldest libraries in the world and contains one of the most significant collections of historical texts. Formally established in 1475, though in fact much older, it has 75,000 codices from...

 and published in 1897. It was followed later the same year by a smaller second work, his Opus Minus, which was intended as an abstract or summary of the longer work, followed shortly by a third work, Opus Tertium, as a preliminary introduction to the other two.

The Opus Majus is divided into seven parts:

• Part one considers the obstacles to real wisdom and truth, classifying the causes of error (offendicula) into four categories: following a weak or unreliable authority, custom, the ignorance of others, and concealing one's own ignorance by pretended knowledge.
• Part two considers the relationship between philosophy
  Philosophy
  Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...
  
   and theology
  Theology
  Theology is the systematic and rational study of religion and its influences and of the nature of religious truths, or the learned profession acquired by completing specialized training in religious studies, usually at a university or school of divinity or seminary.-Definition:Augustine of Hippo...
  
  , concluding that theology (and particularly Holy Scripture) is the foundation of all sciences.
• Part three contains a study of Bibilical language
  Language
  Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...
  
  s: Latin
  Latin
  Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
  
  , Greek
  Greek language
  Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
  
  , Hebrew, and Arabic, as a knowledge of language and grammar is necessary to understand revealed wisdom.
• Parts four, five, and six consider, respectively, mathematics
  Mathematics
  Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
  
  , optics
  Optics
  Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...
  
  , and experimental science. They include a review of alchemy
  Alchemy
  Alchemy is an influential philosophical tradition whose early practitioners’ claims to profound powers were known from antiquity. The defining objectives of alchemy are varied; these include the creation of the fabled philosopher's stone possessing powers including the capability of turning base...
  
   and the manufacture of gunpowder
  Gunpowder
  Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...
  
   and of the positions and sizes of the celestial bodies, and anticipates later invention
  Invention
  An invention is a novel composition, device, or process. An invention may be derived from a pre-existing model or idea, or it could be independently conceived, in which case it may be a radical breakthrough. In addition, there is cultural invention, which is an innovative set of useful social...
  
  s, such as microscope
  Microscope
  A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...
  
  s, telescope
  Telescope
  A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
  
  s, spectacle
  Spectacle
  In general, spectacle refers to an event that is memorable for the appearance it creates. Derived in Middle English from c. 1340 as "specially prepared or arranged display" it was borrowed from Old French spectacle, itself a reflection of the Latin spectaculum "a show" from spectare "to view,...
  
  s, flying machine
  Flying Machine
  "Flying Machine" is a two-track, US-only, promotional CD single release by British rock band The Stairs. Both tracks on the single also appear on the album Mexican R'n'B....
  
  s, hydraulics and steam ships. The study of optics in part five seems to draw on the works of the Arab writers Kindi
  Kindi
  Kindi may refer to:* The Arabic nisbat Al-Kindi which indicates affiliation with the Arabian Kinda tribe.*Kindi Department, one of the 13 departments of the Boulkiemdé Province of Burkina Faso.**Kindi, the capital of Kindi Department*Kindergarten...
  
   and Alhazen, including a discussion of the physiology
  Physiology
  Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
  
   of eyesight, the anatomy
  Anatomy
  Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
  
   of the eye
  Human eye
  The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
  
   and the brain
  Human brain
  The human brain has the same general structure as the brains of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size. Estimates for the number of neurons in the human brain range from 80 to 120 billion...
  
  , and considers light
  Light
  Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
  
  , distance, position, and size, direct vision, reflected
  Reflection (physics)
  Reflection is the change in direction of a wavefront at an interface between two differentmedia so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves...
  
   vision, and refraction
  Refraction
  Refraction is the change in direction of a wave due to a change in its speed. It is essentially a surface phenomenon . The phenomenon is mainly in governance to the law of conservation of energy. The proper explanation would be that due to change of medium, the phase velocity of the wave is changed...
  
  , mirror
  Mirror
  A mirror is an object that reflects light or sound in a way that preserves much of its original quality prior to its contact with the mirror. Some mirrors also filter out some wavelengths, while preserving other wavelengths in the reflection...
  
  s and lenses
  Lens (optics)
  A lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. A simple lens consists of a single optical element...
  
  .
• Part seven considers moral philosophy and ethics.

An incomplete version of Bacon's Opus Majus was published by William Bowyer

William Bowyer

William Bowyer was an English printer.Born in London, he was educated at St John's College, Cambridge, and in 1722 became a partner in his father's business. In 1729 he was appointed printer of the votes of the British House of Commons, and in 1736 printer to the Society of Antiquaries, of which...

 in London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

 in 1733. It was edited by Samuel Jebb

Samuel Jebb

-Life:He was born about 1694, probably at Mansfield, Nottinghamshire, the second son of Samuel Jebb, a maltster. His eldest brother, Richard, settled in Ireland. Another brother, John, became dean of Cashel, and was father of Dr. John Jebb, the Socinian....

 from a manuscript at Trinity College, Cambridge

Trinity College, Cambridge

Trinity College is a constituent college of the University of Cambridge. Trinity has more members than any other college in Cambridge or Oxford, with around 700 undergraduates, 430 graduates, and over 170 Fellows...

 which omitted the seventh part.

As a recent paper emphasizes, this major work can not be usefully read exclusively in the context of the history of science and philosophy while forgetting to consider Bacon's religious commitment to the Franciscan Order. "His Opus maius was a plea for reform addressed to the supreme spiritual head of the Christian faith

Pope

The Pope is the Bishop of Rome, a position that makes him the leader of the worldwide Catholic Church . In the Catholic Church, the Pope is regarded as the successor of Saint Peter, the Apostle...

, written against a background of apocalyptic

Apocalypse

An Apocalypse is a disclosure of something hidden from the majority of mankind in an era dominated by falsehood and misconception, i.e. the veil to be lifted. The Apocalypse of John is the Book of Revelation, the last book of the New Testament...

 expectation and informed by the driving concerns of the friars. It was designed to improve training for missionaries

Missionary

A missionary is a member of a religious group sent into an area to do evangelism or ministries of service, such as education, literacy, social justice, health care and economic development. The word "mission" originates from 1598 when the Jesuits sent members abroad, derived from the Latin...

 and to provide new skills to be employed in the defence of the Christian world against the enmity of non-Christians and of the Antichrist

Antichrist

The term or title antichrist, in Christian theology, refers to a leader who fulfills Biblical prophecies concerning an adversary of Christ, while resembling him in a deceptive manner...

".

External links

• Works of Roger Bacon in the Internet Archive