The 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 and
theology, concluding that theology (and particularly
Holy Scripture) is the foundation of all sciences. • Part three contains a study of Biblical
languages:
Latin,
Greek,
Hebrew, and
Arabic, as a knowledge of language and grammar is necessary to understand revealed wisdom. • Part four contains a study of
Mathematics: As part of the study, he vividly drew out the flaws in the
Julian Calendar, proposing to drop a day every 125 years from 325 CE (
Council of Nicaea). He also noted the shifting of the
Equinoxes to the
Solstices. • Part five contains a study of
Optics: The study of optics in part five seems to draw on the works of the Arab writers
Kindi and
Alhazen, including a discussion of the
physiology of
eyesight, the
anatomy of the
eye and the
brain, and considers
light, distance, position, and size, direct vision,
reflected vision, and
refraction,
mirrors and
lenses. • Part six,
De scientia experimentalis, a study of
Experimental Science: It includes a review of
alchemy, the creation of gunpowder and of the positions and sizes of the
celestial bodies, and anticipates later
inventions, such as
microscopes,
telescopes,
spectacles,
flying machines,
hydraulics and
steam ships. The
occult overtones of this section reflect Bacon's interest in
magic, which he also wrote about in
De secretis operibus artis et naturae, et de nullitate magiae. It was a major influence on
John Dee's theory of
Archemastrie. • Part seven considers moral philosophy and
ethics. Historian Amanda Power emphasizes that this major work cannot 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, written against a background of apocalyptic expectation and informed by the driving concerns of the friars. It was designed to improve training for missionaries 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". studies, from ==Publication history==