“Thus possessing, in the acquirements and habits of his own mind, abundant examples of the nature of knowledge and of the process of invention, Roger Bacon felt also a deep interest in the growth and progress of science, a spirit of inquiry respecting the causes which produced or prevented its advance, and a fervent hope and trust in its future destinies; and these feelings impelled him to speculate worthily and wisely respecting a Reform of the Method of Philosophizing. The manuscripts of his works have existed for nearly six hundred years in many of the libraries of Europe, and especially in those of England; and for a long period the very imperfect portions of them which were [514] generally known, left the character and attainments of the author shrouded in a kind of mysterious obscurity. About a century ago, however, his Opus Majus was published[5] by Dr. S. Jebb, principally from a manuscript in the library of Trinity College, Dublin; and this contained most or all of the separate works which were previously known to the public, along with others still more peculiar and characteristic. We are thus able to judge of Roger Bacon’s knowledge and of his views, and they are in every way well worthy our attention.

[5] Fratris Rogeri Bacon Ordinis Minorum Opus Majus ad Clementem Quartum, Pontificem Romanum, ex MS. Codice Dubliniensi cum aliis quibusdam collato nunc primum edidit S. Jebb, M.D. Londini, 1733.

“The Opus Majus is addressed to Pope Clement the Fourth, whom Bacon had known when he was legate in England as Cardinal-bishop of Sabina, and who admired the talents of the monk, and pitied him for the persecutions to which he was exposed. On his elevation to the papal chair, this account of Bacon’s labours and views was sent, at the earnest request of the pontiff. Besides the Opus Majus, he wrote two others, the Opus Minus and Opus Tertium; which were also sent to the pope, as the author says,[6] ‘on account of the danger of roads, and the possible loss of the work.’ These works still exist unpublished, in the Cottonian and other libraries.

[6] Opus Majus, Præf.

“The Opus Majus is a work equally wonderful with regard to its general scheme, and to the special treatises with which the outlines of the plan are filled up. The professed object of the work is to urge the necessity of a reform in the mode of philosophizing, to set forth the reasons why knowledge had not made a greater progress, to draw back attention to the sources of knowledge which had been unwisely neglected, to discover other sources which were yet almost untouched, and to animate men in the undertaking, by a prospect of the vast advantages which it offered. In the developement of this plan, all the leading portions of science are expounded in the most complete shape which they had at that time assumed; and improvements of a very wide and striking kind are proposed in some of the principal of these departments. Even if the work had had no leading purpose, it would have been highly valuable as a treasure of the most solid knowledge and soundest speculations of the time; even if it had contained no such details, it would have been a work most remarkable for its general views and scope. It may be considered as, at the same time, the Encyclopedia and the Novum Organon of the thirteenth century. [515]

“Since this work is thus so important in the history of Inductive Philosophy I shall give, in a Note, a view[7] of its divisions and contents. But I must now endeavor to point out more especially the way in which the various principles, which the reform of scientific method involved, are here brought into view.

[7] Contents of Roger Bacon’s Opus Majus:

Part I.On the four causes of humanignorance:—Authority, Custom, Popular Opinion, and the Pride ofsupposed Knowledge.
Part II.On the source of perfect wisdom in theSacred Scripture.
Part III.On the Usefulness of Grammar.
Part IV. On the Usefulnessof Mathematics.
(1.) The Necessity ofMathematics in Human Things (published separately as the SpeculaMathematica).
(2.) The Necessity ofMathematics in Divine Things.—1°. This study has occupied holymen: 2°. Geography: 3°. Chronology: 4°. Cycles; the Golden Number,&c.: 5°. Natural Phenomena, as the Rainbow: 6°. Arithmetic: 7°.Music.
(3.) The Necessity ofMathematics in Ecclesiastical Things. 1°. The Certification of Faith:2°. The Correction of the Calendar.
(4.) The Necessity ofMathematics in the State.—1°. Of Climates: 2°. Hydrography: 3°.Geography: 4°. Astrology.
Part V. On Perspective(published separately as Perspectiva).
(1.) The organs of vision.
(2.) Vision in straight lines.
(3.) Vision reflected andrefracted.
(4.) De multiplicationespecierum (on the propagation of the impressions of light, heat,&c.)
Part VI. On ExperimentalScience.

“One of the first points to be noticed for this purpose, is the resistance to authority; and at the stage of philosophical history with which we here have to do, this means resistance to the authority of Aristotle, as adopted and interpreted by the Doctors of the Schools. Bacon’s work[8] is divided into Six Parts; and of these Parts, the First is, Of the four universal Causes of all Human Ignorance. The causes thus enumerated[9] are:—the force of unworthy authority;—traditionary habit;—the imperfection of the undisciplined senses;—and the disposition to conceal our ignorance and to make an ostentatious show of our knowledge. These influences involve every man, occupy every condition. They prevent our obtaining the most useful and large and fair doctrines of wisdom, the secrets of all sciences and arts. He then proceeds to argue, from the testimony of philosophers themselves, that the authority of antiquity, and especially of Aristotle, is not infallible. ‘We find[10] their books full of doubts, obscurities, and perplexities. They [516] scarce agree with each other in one empty question or one worthless sophism, or one operation of science, as one man agrees with another in the practical operations of medicine, surgery, and the like arts of secular men. Indeed,’ he adds,[11] ‘not only the philosophers, but the saints have fallen into errors which they have afterwards retracted,’ and this he instances in Augustin, Jerome, and others. He gives an admirable sketch of the progress of philosophy from the Ionic School to Aristotle; of whom he speaks with great applause. ‘Yet,’ he adds, ‘those who came after him corrected him in some things, and added many things to his works, and shall go on adding to the end of the world.’ Aristotle, he adds, is now called peculiarly[12] the Philosopher, ‘yet there was a time when his philosophy was silent and unregarded, either on account of the rarity of copies of his works, or their difficulty, or from envy; till after the time of Mahomet, when Avicenna and Averroes, and others, recalled this philosophy into the full light of exposition. And although the Logic and some other works were translated by Boethius from the Greek, yet the philosophy of Aristotle first received a quick increase among the Latins at the time of Michael Scot; who, in the year of our Lord 1230, appeared, bringing with him portions of the books of Aristotle on Natural Philosophy and Mathematics. And yet a small part only of the works of this author is translated, and a still smaller part is in the hands of common students.’ He adds further[13] (in the Third Part of the Opus Majus, which is a Dissertation on Language) that the translations which are current of these writings, are very bad and imperfect. With these views, he is moved to express himself somewhat impatiently[14] respecting these works: ‘If I had,’ he says, ‘power over the works of Aristotle, I would have them all burnt; for it is only a loss of time to study in them, and a course of error, and a multiplication of ignorance beyond expression.’ ‘The common herd of students,’ he says, ‘with their heads, have no principle by which they can be excited to any worthy employment; and hence they mope and make asses of themselves over their bad translations, and lose their time, and trouble, and money.’

[8] Op. Maj. p. 1.