§ 111. ROGER BACON. 695
With Anaxagoras, he ascribed the Nile to the melting of the snows in Ethiopia.1 He was not the inventor of gunpowder of which the Arabs knew.
Bacon's works, so far as they are published, combine the study of theology, philosophy, and what may be called the physical sciences. His Opus majus in seven books, the Opus minus, and Opus tertium are measurably complete. Of his Scriptum principale or Compendium studii philosophic, often referred to in the writings just mentioned, only fragments were written, and of these only portions are left. The work was intended to be in four volumes and to include a treatment of grammar and logic, mathematics, physics, and last meta physics and morals. The Oommunio naturalium and other treatises are still in manuscript.
The Opus majus in its list of subjects is the most encyclo paedic work of the Middle Ages. It takes up as separate departments the connection of philosophy and theology, astronomy including geography, astrology, barology, al chemy, agriculture, optics or perspective, and moral philos ophy, medicine and experimental science, scientia experimentalis.
By agriculture, he meant the study of the vegetable and ani mal worlds, and such questions as the adaptation of soil to dif ferent classes of plants. In the treatment of optics he presents the construction of the eye and the laws of vision. Mathe matics are the foundation of all science and of great value for the Church. Alchemy deals with liquids, gases, and solids, and their generation. A child of his age, Bacon held that met als were compound bodies whose elements can be separated. 2 In the department of astrology, in accordance with the opin ions prevailing in his day, he held that the stars and planets have an influence upon all terrestrial conditions and objects,
1 1. 323.
2 As an illustration of some of Bacon's chemical and medical advice the following receipt may be given. He says a combination of gold, pearl, flower of sea dew, spermaceti, aloes, bone of stag's heart, flesh of Tyrian snake, and Ethiopian dragon, properly prepared in due portions, might promote longevity to a length hitherto unimagined. Op. wry., II. 206.
696 THE MIDDLE AGES. A.D. 1049-1294.
including man. Climate, temperament, motion, all are more or less dependent upon their potency. As the moon affects the tides, so the stars implant dispositions good and evil. This potency influences but does not coerce man's free will. The comet of 1264, due to Mars, was related to the wars of England, Spain, and Italy.1 In the department of optics and the teachings in regard to force, he was far ahead of his age and taught that all objects were emitting force in all directions. Experimental science governs all the preceding sciences. Knowledge comes by reasoning and experience. Doubts left by reasoning are tried by experience, which is the ultimate test of truth.
The practical tendency of Bacon's mind is everywhere apparent. He was an apostle of common sense. Speaking of Peter of Maricourt of Paris, otherwise unknown, he praises him for his achievements in the science of experimental research and said: "Of discourses and battles of words he takes no heed. Through experiment he gains knowledge of natural things, medical, chemical, indeed of everything in the heavens and the earth. He is ashamed that things should be known to laymen, old women, soldiers, and ploughmen, of which he is himself ignorant." He also confessed he had learned incomparably more from men unlettered and unknown to the learned than he had learned from his most famous teachers.2
Bacon attacked the pedantry of the scholastic method, the frivolous and unprofitable logomachy over questions which were above reason and untaught by revelation. Again and again he rebuked the conceit and metaphysical abstruseness of the theological writers of his century, especially Alexander of Hales and also Albertus Magnus and Thomas Aquinas. He used, at length, Alfarabius, Avicenna, Algazel, and other Arabic philosophers, as well as Aristotle. Against the pride and avarice and ignorance of the clergy he spoke with un measured severity and declared that the morals of Seneca and his age were far higher than the morals of the thirteenth
1 Op. maj., I. 385 sqq. 2 Bridges' ed., Op. maj., I. pp. xxv., 23.