BACON, ROGER (c.1214-c.1294), English philosopher and man of science, was born near Ilchester in Somerset. His family appears to have been in good circumstances, but in the stormy reign of Henry III. their property was despoiled and several members of the family were driven into exile. Roger completed his studies at Oxford, though not, as current traditions assert, at Merton or at Brasenose, neither of which had then been founded. His abilities were speedily recognized by his contemporaries, and he enjoyed the friendship of such eminent men as Adam de Marisco and Robert Grosseteste, bishop of Lincoln.
Very little is known of Bacon's life at Oxford; it is said he took orders in 1233, and this is not improbable. In the following year, or perhaps later, he crossed over to France and studied at the university of Paris, then the centre of intellectual life in Europe. The two great orders, Franciscans and Dominicans, were in the vigour of youth, and had already begun to take the lead in theological discussion. Alexander of Hales was the oracle of the Franciscans, while the rival order rejoiced in Albertus Magnus and Thomas Aquinas.
The scientific training which Bacon had received, mainly from the study of the Arab writers, showed him the manifold defects in the systems reared by these doctors. Aristotle was known but in part, and that part was rendered well-nigh unintelligible through the vileness of the translations; yet not one of those professors would learn Greek. The Scriptures read, if at all, in the erroneous versions were being deserted for the Sentences of Peter Lombard. Physical science, if there was anything deserving that name, was cultivated, not by experiment in the Aristotelian way, but by arguments deduced from premises resting on authority or custom. Everywhere there was a show of knowledge concealing fundamental ignorance. Bacon, accordingly, withdrew from the scholastic routine and devoted himself to languages and experimental research. The only teacher whom he respected was a certain Petrus de Maharncuria Picardus, or of Picardy, probably identical with a certain mathematician, Petrus Peregrinus of Picardy, who is perhaps the author of a MS. treatise, De Magnete, contained in the Bibliothèque Impériale at Paris. The contrast between the obscurity of such a man and the fame enjoyed by the fluent young doctors roused Bacon's indignation. In the Opus Minus and Opus Tertium he pours forth a violent tirade against Alexander of Hales, and another professor, not mentioned by name, but spoken of as alive, and blamed even more severely than Alexander. This anonymous writer, he says, acquired his learning by teaching others, and adopted a dogmatic tone, which has caused him to be received at Paris with applause as the equal of Aristotle, Avicenna, or Averroes.
Bacon, during his stay in Paris, acquired considerable renown. He took the degree of doctor of theology, and seems to have received the complimentary title of doctor mirabilis. In 1250 he was again at Oxford, and probably about this time entered the Franciscan order. His fame spread at Oxford, though it was mingled with suspicions of his dealings in the black arts and with some doubts of his orthodoxy. About 1257, Bonaventura, general of the order, interdicted his lectures at Oxford, and commanded him to place himself under the superintendence of the body at Paris. Here for ten years he remained under supervision, suffering great privations and strictly prohibited from writing anything for publication. But his fame had reached the ears of the papal legate in England, Guy de Foulques, who in 1265 became pope as Clement IV. In the following year he wrote to Bacon, ordering him notwithstanding any injunctions from his superiors, to write out and send to him a treatise on the sciences which he had already asked of him when papal legate. Bacon, whose previous writings had been mostly scattered tracts, capitula quaedam, took fresh courage from this command of the pope. He set at naught the jealousy of his superiors and brother friars, and despite the want of funds, instruments, materials for copying and skilled copyists, completed in about eighteen months three large treatises, the Opus Majus, Opus Minus and Opus Tertium, which, with some other tracts, were despatched to the pope. We do not know what opinion Clement formed of them, but before his death he seems to have bestirred himself on Bacon's behalf, for in 1268 the latter was permitted to return to Oxford. Here he continued his labours in experimental science and also in the composition of complete treatises. The works sent to Clement he regarded as preliminaries, laying down principles which were afterwards to be applied to the sciences. The first part of an encyclopaedic work probably remains to us in the Compendium Studii Philosophiae (1271). In this work Bacon makes a vehement attack upon the ignorance and vices of the clergy and monks, and generally upon the insufficiency of the existing studies. In 1278 his books were condemned by Jerome de Ascoli, general of the Franciscans, afterwards Pope Nicholas IV., and he himself was thrown into prison for fourteen years. During this time, it is said, he wrote the small tract De Retardandis Senectutis Accidentibus, but this is merely a tradition. In 1292, as appears from what is probably his latest composition, the Compendium Studii Theologiae, he was again at liberty. The exact time of his death cannot be determined; 1294 is probably as accurate a date as can be fixed upon.
Works and Editions. - Leland said that it is easier to collect the leaves of the Sibyl than the titles of the works written by Roger Bacon; and though the labour has been somewhat lightened by the publications of Brewer and Charles, referred to below, it is no easy matter even now to form an accurate idea of his actual productions. An enormous number of MSS. are known to exist in British and French libraries, and probably not all have yet been discovered. Many are transcripts of works or portions of works already published and, therefore, require no notice.
The works hitherto printed (neglecting reprints) are the following: - (1) Speculum Alchimiae (1541) - translated into English (1597); French, A Poisson (1890); (2) De Mirabili Potestate Artis et Naturae (1542) - English translation (1659); (3) Libellus de Retardandis Senectutis Accidentibus (1590) - translated as the "Cure of Old Age," by Richard Brown (London, 1683); (4) Sanioris Medicinae Magistri D. Rogeri Baconis Anglici de Arte Chymiae Scripta (Frankfort, 1603) - a collection of small tracts containing Excerpta de Libra Avicennae de Anima, Breve Breviarium, Verbum Abbreviatum, Secretum Secretorum, Tractatus Trium Verborum, and Speculum Secretorum; (5) Perspectiva (1614), which is the fifth part of the Opus Majus; (6) Specula Mathematica, which is the fourth part of the same; (7) Opus Majus ad Clementem IV., edited by S. Jebb (1733) and J. H. Bridges (London, 1897); (8) Opera hactenus Inedita, by J. S. Brewer (1859), containing the Opus Tertium, Opus Minus, Compendium Studii Philosophiae and the De Secretis Operibus Naturae; (9) De Morali Philosophia (Dublin, 1860, see below); (10) The Greek Grammar of R. Bacon and a Fragment of his Hebrew Grammar, edited with introduction and notes by E. S. Nolan and S. A. Hirsch (1902); (11) Metaphysica Fratris Rogeri, edited by R. Steele, with a preface (1905); (12) Opera hactenus inedita, by Robert Steele (1905).
How these works stand related to one another can only be determined by internal evidence. The smaller works, chiefly on alchemy, are unimportant, and the dates of their composition cannot be ascertained. It is known that before the Opus Majus Bacon had already written some tracts, among which an unpublished work, Computus Naturalium, on chronology, belongs probably to the year 1263; while, if the dedication of the De Secretis Operibus be authentic, that short treatise must have been composed before 1249.
It is, however, with the Opus Majus that Bacon's real activity begins. It has been called by Whewell at once the Encyclopaedia and the Organum of the 13th century.
Part I. (pp. 1-22), which is sometimes designated De Utililate Scientiarum, treats of the four offendicula, or causes of error. These are, authority, custom, the opinion of the unskilled many, and the concealment of real ignorance with pretence of knowledge. The last error is the most dangerous, and is, in a sense, the cause of all the others. The offendicula have sometimes been looked upon as an anticipation of Francis Bacon's Idola, but the two classifications have little in common. In the summary of this part, contained in the Opus Tertium, Bacon shows very clearly his perception of the unity of science and the necessity of encyclopaedic treatment.
Part II. (pp. 23-43) treats of the relation between philosophy and theology. All true wisdom is contained in the Scriptures, at least implicitly; and the true end of philosophy is to rise from the imperfect knowledge of created things to a knowledge of the Creator. Ancient philosophers, who had not the Scriptures, received direct illumination from God, and only thus can the brilliant results attained by them be accounted for.
Part III. (pp. 44-57) treats of the utility of grammar, and the necessity of a true linguistic science for the adequate comprehension either of the Scriptures or of books on philosophy. The necessity of accurate acquaintance with any foreign language and of obtaining good texts, is a subject Bacon is never weary of descanting upon. A translator should know thoroughly the language he is translating from, the language into which he is translating, and the subject of which the book treats.
Part IV. (pp. 57-255) contains an elaborate treatise on mathematics, "the alphabet of philosophy," maintaining that all the sciences rest ultimately on mathematics, and progress only when their facts can be subsumed under mathematical principles. This fruitful thought he illustrates by showing how geometry is applied to the action of natural bodies, and demonstrating by geometrical figures certain laws of physical forces. He also shows how his method may be used to determine some curious and long-discussed problems, such as the light of the stars, the ebb and flow of the tide, the motion of the balance. He then proceeds to adduce elaborate and sometimes slightly grotesque reasons tending to prove that mathematical knowledge is essential in theology, and closes this section of his work with two comprehensive sketches of geography and astronomy. That on geography is particularly good, and is interesting as having been read by Columbus, who lighted on it in Petrus de Alliaco's Imago Mundi, and was strongly influenced by its reasoning.
Part V. (pp. 256-357) treats of perspective. This was the part of his work on which Bacon most prided himself, and in it, we may add, he seems to owe most to the Arab writers Kindi and Alhazen. The treatise opens with an able sketch of psychology, founded upon, but in some important respects varying from, Aristotle's De Anima. The anatomy of the eye is next described; this is done well and evidently at first hand, though the functions of the parts are not given with complete accuracy. Many other points of physiological optics are touched on, in general erroneously. Bacon then discusses vision in a right line, the laws of reflection and refraction, and the construction of mirrors and lenses. In this part of the work, as in the preceding, his reasoning depends essentially upon his peculiar view of natural agents and their activities. His fundamental physical maxims are matter and force; the latter he calls virtus, species, imago agentis, and by numberless other names. Change, or any natural phenomenon, is produced by the impression of a virtus or species on matter - the result being the thing known. Physical action is, therefore, impression, or transmission of force in lines, and must accordingly be explained geometrically. This view of nature Bacon considered fundamental, and it lies, indeed, at the root of his whole philosophy. To the short notices of it given in the 4th and 5th parts of the Opus Majus, he subjoined two, or perhaps three, extended accounts of it. We possess at least one of these in the tract De Multiplicatione Specierum, printed as part of the Opus Majus by Jebb (pp. 358-444). We cannot do more than refer to Charles for discussions as to how this theory of nature is connected with the metaphysical problems of force and matter, with the logical doctrine of universals, and in general with Bacon's theory of knowledge.
Part VI. (pp. 445-477) treats of experimental science, domina omnium scientiarum. There are two methods of knowledge: the one by argument, the other by experience. Mere argument is never sufficient; it may decide a question, but gives no satisfaction or certainty to the mind, which can only be convinced by immediate inspection or intuition. Now this is what experience gives. But experience is of two sorts, external and internal; the first is that usually called experiment, but it can give no complete knowledge even of corporeal things, much less of spiritual. On the other hand, in inner experience the mind is illuminated by the divine truth, and of this supernatural enlightenment there are seven grades.
Experimental science, which in the Opus Tertium (p. 46) is distinguished from the speculative sciences and the operative arts in a way that forcibly reminds us of Francis Bacon, is said to have three great prerogatives over all other sciences: - (1) It verifies their conclusions by direct experiment; (2) It discovers truths which they could never reach; (3) It investigates the secrets of nature, and opens to us a knowledge of past and future. As an instance of his method, Bacon gives an investigation into the nature and cause of the rainbow, which is really a very fine specimen of inductive research.
The seventh part of the Opus Majus (De Morali Philosophia), not given in Jebb's edition, is noticed at considerable length in the Opus Tertium (cap. xiv.). Extracts from it are given by Charles (pp. 339-348).
As has been seen, Bacon had no sooner finished this elaborate work than he began to prepare a summary to be sent along with it. Of this summary, or Opus Minus, part has come down and is published in Brewer's Op. Ined. (313-389), from what appears to be the only MS. The work was intended to contain an abstract of the Opus Majus, an account of the principal vices of theology, and treatises on speculative and practical alchemy. At the same time, or immediately after, Bacon began a third work as a preamble to the other two, giving their general scope and aim, but supplementing them in many points. The part of this work, generally called Opus Tertium, is printed by Brewer (pp. 1-310), who considers it to be a complete treatise. Charles, however, has given good grounds for supposing that it is merely a preface, and that the work went on to discuss grammar, logic (which Bacon thought of little service, as reasoning was innate), mathematics, general physics, metaphysics and moral philosophy. He founds his argument mainly on passages in the Communia Naturalium, which indeed prove distinctly that it was sent to Clement, and cannot, therefore, form part of the Compendium, as Brewer seems to think. It must be confessed, however, that nothing can well be more confusing than the references in Bacon's works, and it seems well-nigh hopeless to attempt a complete arrangement of them until the texts have been collated and carefully printed.
All these large works Bacon appears to have looked on as preliminaries, introductions, leading to a great work which should embrace the principles of all the sciences. This great work, which is perhaps the frequently-referred-to Liber Sex Scientiarum, he began, and a few fragments still indicate its outline. First appears to have come the treatise now called Compendium Studii Philosophiae (Brewer pp. 393-519), containing an account of the causes of error, and then entering at length upon grammar. After that, apparently, logic was to be treated; then, possibly, mathematics and physics; then speculative alchemy and experimental science. It is, however, very difficult, in the present state of our knowledge of the MSS., to hazard even conjectures as to the contents and nature of this last and most comprehensive work.
Bacon's fame in popular estimation has always rested on his mechanical discoveries. Careful research has shown that very little can with accuracy be ascribed to him. He certainly describes a method of constructing a telescope, but not so as to lead one to conclude that he was in possession of that instrument. Burning-glasses were in common use, and spectacles it does not appear he made, although he was probably acquainted with the principle of their construction. His wonderful predictions (in the De Secretis) must be taken cum grano salis; he believed in astrology, in the doctrine of signatures, and in the philosopher's stone, and knew that the circle had been squared. For his work in connexion with gunpowder, the invention of which has been claimed for him on the ground of a passage in his De mirabili potestate artis et naturae, see Gunpowder.
Summary. - The 13th century, an age peculiarly rich in great men, produced few, if any, who can take higher rank than Roger Bacon. He is in every way worthy to be placed beside Albertus Magnus, Bonaventura, and Thomas Aquinas. These had an infinitely wider renown in their day, but modern criticism has restored the balance in his favour, and is even in danger of erring in the opposite direction. Bacon, it is now said, was not appreciated by his age because he was in advance of it; he is no schoolman, but a modern thinker, whose conceptions of science are more just and clear than are even those of his more celebrated namesake. In this view there is certainly some truth, but it is much exaggerated. As a general rule, no man can be completely dissevered from his national antecedents and surroundings, and Bacon is not an exception. Those who take up such an extreme position regarding his merits have known too little of the state of contemporary science, and have limited their comparison to the works of the scholastic theologians. We never find in Bacon himself any consciousness of originality; he is rather a keen and systematic thinker, working in a well-beaten track, from which his contemporaries were being drawn by theology and metaphysics.
Bibliography. - The best work on Roger Bacon is perhaps that of E. Charles, Roger Bacon, sa vie, ses ouvrages, ses doctrines d'après des textes inédits (1861). Against the somewhat enthusiastic estimate and modern interpretation given in this work, are Schneider in his Roger Bacon, Eine Monographie (Augsburg, 1873); K. Werner, Die Psychol. ... des Roger Bacon and Die Kosmologie ... des Roger Bacon (Vienna, 1879); S. A. Hirsch, Early English Hebraists (1899); Book of Essays (London, 1905), deals with Bacon as a Hebraist. The new matter contained in the publications of Charles and Brewer was summarized by H. Siebert, Roger Bacon: Inaugural Dissertation (Marburg, 1861). Cf. also J. K. Ingram, On the Opus Majus of Bacon (Dublin, 1858); Cousin, "Fragments phil. du moyen âge" (reprinted from Journal des savans, 1848); E. Saisset, "Précurseurs et disciples de Descartes," pp. 1-58 (reprinted from Revue de deux mondes, 1861); K. Prantl, Gesch. der Logik, iii. 120-129 (a severe criticism of Bacon's logical doctrines); Held, Roger Bacon's praktische Philosophie (Jena, 1881); Karl Pohl, Das Verhältniss d. Philos. zur Theol. bei Roger Bacon (Neustrelitz, 1893); articles in Westminster Review, lxxxi. 1 and 512; A. Parrot, Roger Bacon et ses contemporains (1894); E. Fluegel, Roger Bacons Stellung in d. Gesch. d. Philos. (1902); S. Vogl, Die Physik Roger Bacos (1906). For the popular legend see Famous Historie of Fryer Bacon (London, 1615; reproduced in Thoms, Early Prose Romances, iii.); R. Greene's Friar Bacon and Friar Bungay (1587 or 1588), and in publication of the Percy Society, vol. xv. 1844, A Piece of Friar Bacon's Brazen Heade's Prophesie (1604). For Bacon as a classical scholar see J. E. Sandys, Hist. of Class. Schol. (2nd ed., 1906), cxxxi.
(R. Ad.; X.)
 Brewer thinks this unknown professor is Richard of Cornwall, but the little we know of Richard is not in harmony with the terms in which he is elsewhere spoken of by Bacon. Erdmann conjectures Thomas Aquinas, which is extremely improbable, as Thomas was unquestionably not the first of his order to study philosophy. Cousin and Charles think that Albertus Magnus is aimed at, and certainly much of what is said applies with peculiar force to him. But some things do not at all cohere with what is otherwise known of Albert. It is worth pointing out that Brewer, in transcribing the passage bearing on this (Op. Ined. p. 327), has the words fratrum puerulus, which in his marginal note he interprets as applying to the Franciscan order. In this case, of course, Albert could not be the person referred to, as he was a Dominican. But Charles, in his transcription, entirely omits the important word fratrum.
 The more important MSS. are: - (1) The extensive work on the fundamental notions of physics, called Communia Naturalium, which is found in the Mazarin library at Paris, in the British Museum, and in the Bodleian and University College libraries at Oxford; (2) on the fundamental notions of mathematics, De Communibus Mathematicae, part of which is in the Sloane collection, part in the Bodleian; (3) Baconis Physica, contained among the additional MSS. in the British Museum; (4) the fragment called Quinta Pars Compendii Theologiae, in the British Museum; (5) the Compendium Studii Theologiae, in the British Museum; (6) the logical fragments, such as the Summulae Dialectices, in the Bodleian, and the glosses upon Aristotle's physics and metaphysics in the library at Amiens. See Little, The Grey Friars in Oxford (1892).
 At the close of the Verb. Abbrev. is a curious note, concluding with the words, "ipse Rogerus fuit discipulus fratris Alberti!"
 See Dühring, Kritische Ges. d. Phil. 192, 249-251.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)