The Place of Magic in the Intellectual History of Europe/Chapter 1

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The Place of Magic in the Intellectual History of Europe
by Lynn Thorndike
Chapter I
2321997The Place of Magic in the Intellectual History of Europe — Chapter ILynn Thorndike

CHAPTER I

Illustrations of Belief in Magic in Mediæval and
in Early Modern Times

Even a slight acquaintance with European history reveals the existence of a number of curious and apparently unreasonable beliefs prevalent throughout a period extending from early mediæval to comparatively recent times. There is the belief in witchcraft, for instance. From the canons of synods in the early Middle Ages down to the pitiless executions during the witchcraft delusion, there is abundant evidence of its prominence. It played its part not only in humble life, but in court intrigues and in the accusations brought at state trials.

The belief that one's future could be learned by observing the stars was equally widespread. Astrologers throve at the courts of kings, and sometimes their advice was taken even by him whose every act was held to be under special divine direction. It would be a great mistake to think that the astrologer was maintained merely for the amusement of king and court, like the jester. His utterances were taken most seriously, and the principles of his art were so generally accepted as to become the commonplaces of the thought and the conversation of daily life. In 1305, for instance, when certain cardinals urged Pope Clement V to return to Rome, they reminded him that every planet was most powerful in its own house.[1] Indeed, even in our speech to-day numerous vestiges of the astrological art survive.[2]

Moreover, a grander and more imposing witchcraft displayed itself in the stories of the wizard Merlin and in the persons of the wicked magicians with whom knights contended in the pages of mediæval romance. So strong was the tendency to believe in the marvelous, that men of learning were often pictured by subsequent tradition, if not by contemporary gossip, as mighty necromancers. Even Gerbert, who seems to have done nothing more shocking than to write a treatise on the abacus and build a pipe-organ, was pictured as running off with a magician's book and daughter, hanging under bridges between earth and water to escape noxious spells, and making compacts with Satan.[3]

The attitude of the average mind as it has just been illustrated was to a large extent characteristic of the best instructed and most widely read men. The erudite poet Dante accepted the influence of the constellations upon human destiny. Bodin maintained in his Republic—perhaps the greatest book on political science written during the sixteenth century—that astrology was very useful in tracing the development of society.[4] Aquinas, chief of the mediæval theologians, accepted astrological theory, except as limited by human free will, and further admitted that most men make little use of their liberty of action but blindly follow their passions, which are governed by the stars.[5] Among other great mediæval churchmen and canonists, d'Ailly and Gerson both believed that God signified important events in advance through the stars, and d'Ailly made some astrological predictions himself. Astrology was much taught in the mediæval universities,[6] and was regarded as the climax of mathematics and as an essential part of medicine.

It is with such beliefs, accepted by educated men and forming a part of the learning and science of the times, that we are concerned in this essay. First, it is necessary to give some further evidence of the nature and of the general acceptance of these beliefs. This object will be most quickly and effectively secured by a résumé of the views of a few of the men most prominent in the intellectual history of the past. These men should offer fair, if not flattering, illustrations of the learning and culture of their times. In especial we shall notice the curious notions of those who wrote on scientific subjects or showed even a considerable approach towards the modern scientific spirit. This we shall do partly because their writings seem at first thought the place where we should least expect to find such notions, and hence furnish striking illustration of the almost universal acceptance of these beliefs; partly because, as we shall soon find reason to conclude, there is really some connection between such beliefs and science.

The early Middle Ages are not distinguished for the prevalence of education and of culture in Latin Christendom, to say nothing of profound knowledge or original thought in any particular branch of learning. But in such learning and science as there was may be found examples of the beliefs which we wish to consider. We see them in Isidore of Seville, whose Etymologies, we may well believe, constituted an oft-consulted encyclopedia in many a monastic library for several centuries after the seventh, when it appeared. This saint, like almost all good Christians of his day, believed that marvels could be effected through magic by the aid of demons, although such resort to evil spirits he could not condemn too strongly.[7] But he saw no harm in holding that certain stones possess astonishing powers,[8] that the dog-star afflicts bodies with disease, and that the appearance of a comet signifies pestilence, famine or war.[9] He maintained that it was no waste of time to look into the meaning of the numbers which occur in the Bible. He thought that they might reveal many sacred mysteries.[10] Bede expressed similar views in his scientific treatises.[11] Also, if we may regard as his two little essays about the authenticity of which there is some question, he ascribed such extraordinary influence to the moon as to maintain that the practice of bleeding should be regulated by its phases, and wrote—with some hesitation lest he should be accused of magic—an explanation of how to predict coming disasters by observing the time and direction of peals of thunder.[12]

Passing over several centuries during which judicial astrology is very conspicuous in the mathematical treatises which formed the greater part of the scientific literature of the times,[13] we come at the close of the twelfth century to the De Naturis Rerum of Alexander Neckam (1157-1217). We find him ecstatically musing over the consonance of celestial harmony and associating the seven planets with the seven liberal arts and the seven gifts of the Holy Spirit,[14] as if believing that there is some occult virtue in that number or some potent sympathy between these material bodies and such abstractions as branches of learning and generic virtues. Descending from the skies to things earthly—the transition is easy since he believes in the influence, saving human free will, of the planets on our lower creation[15]—he tells us that mugwort prevents the traveler from feeling fatigue,[16] and that the Egyptian fig makes the wrinkles of old age vanish and can tame the fiercest bulls once they are gathered beneath its branches.[17] He describes fountains with properties as marvelous as those of the herb or of the tree.[18] He tells of stones which, placed on the head of the sleeping wife, provoke confession of marital infidelity,[19] or which, extracted from the crop of a rooster and carried in one's mouth, give victory in war.[20] What is more, words as well as plants and stones are found by the careful and industrious investigator of nature to have great virtue, as experiment shows beyond doubt.[21]

Neckam, despite the fact that according to his editor, Thomas Wright, he "not infrequently displays a taste for experimental science,"[22] was, after all, more of a moralizing compiler than anything else. But greater men than Neckam, men who were interested in learning and science for their own sake, men who knew more and wrote more, still cherished beliefs of the same sort. There was Michael Scot in the early years of the thirteenth century, the wonder of the cultured court of Frederick II, perhaps that monarch's tutor, the "Supreme Master" of Paris, the man who helped much to make the treasures of learning amassed by the Arabs in Spain the common property of Latin Christendom, the introducer to Western Europe of a Latin version of Averroes and of an enlarged Aristotle.[23] Scot composed a primer of astrology for young scholars. His writings on alchemy show that he experimented in it not a little. His Physionomia accepts the doctrine of signatures, tells us that these signs on the outward body of the soul's inner state are often discovered through dreams, and contains a chapter giving an extended description of the rules of augury—an art on which the author, though a Christian, apparently bestowed his sanction. Prophetic verses foretelling the fate of several Italian cities have come down to us under his name. A poem of Henri d'Avranches, written in 1235-6, recalls to mind the fact that certain prophecies concerning the emperor had been made by the then deceased Michael Scot, whom the poet proceeds to call a scrutinizer of the stars, an augur, a soothsayer, a veridicus vates, and a second Apollo.[24] A most interesting recipe for invoking demons to instruct one in liberal arts is attributed to Michael Scot in a manuscript collection of Occulta in the Laurentian library.[25]

Later in the same century stands forth the famous figure of Roger Bacon, the stout defender of mathematics and physics against scholasticism. Some have ascribed to him numerous important innovations in the realm of natural science and of the mechanical arts, and have regarded his promulgation of the experimental method, guided by the mathematical method, as the first herald note of that modern science which was not destined really to appear for yet several centuries. Yet he held that the alchemist, if given sufficient time and money, could discover a way not only to meet the state's expenses by converting baser metals into gold, but also to prolong human existence beyond that limit to which it can be drawn out by nature.[26] Indeed these objects constituted two of the three examples he gave of the great advantages to be gained from the pursuit of that experimental science which was to disprove and blot out all magical nonsense.[27]

How far Bacon let the principles of astrology carry him a citation or two will show. That a woman had succeeded in living twenty years without eating was, he explained, no miracle, but due to the fact that during that period some constellation was able to reduce the concourse of the four elements in her body to a greater degree of harmony than they usually attain.[28] Nor is it health alone that the stars control; they affect human character.[29] They implant in the babe at birth good or evil dispositions, great or small talents. Human free will may either better these innate tendencies through God's grace or modify them for the worse by yielding to Satan's temptings; but in general the stars so far prevail that there are different laws and customs and national traits under different quarters of the heavens.[30] Nay more, astrology offers proof of the superiority of Christianity to other religions and gives insight into the nature of Antichrist.[31]

As one might surmise from Bacon's belief in the potent effect of sidereal emanations, he makes much of the theory that every agent sends forth its own virtue and species into external matter. This leads him to accept fascination as a fact. Just as Aristotle tells that in some localities mares become pregnant by the mere odor of the stallions, and as Pliny relates that the basilisk kills by a glance, so the witch by the vapor from her bleary eye draws her victims on to destruction. In short, "Man can project virtue and species outside himself, the more since he is nobler than all corporeal things, and especially because of the virtue of the rational soul."[32] Hence the great effects possible from spoken words or written characters; although one must beware of falling into the absurdities and abominations of the magicians. Bacon, moreover, was like Scot a believer in the doctrine of signatures.[33]

Other men of the same period prominent in science who held similar beliefs we can scarcely stop to mention. There was Vincent de Beauvais, the great encyclopedist, and Bernard Gordon, a physician of Montpellier and a medical writer of considerable note, who nevertheless recommended the use of a magic formula for the treatment of epilepsy.[34] There was Albertus Magnus with his trust in such wonderful powers of stones as to cure ulcers, counteract potions, conciliate human hearts, and win battles; and his theory that ligatures and suspensions, and gems carved with proper images possess similar strange virtues.[35] There was Arnald of Villanova who propounded such admirable doctrines as that a physician ought first of all to understand the chief functions of life and chief organs of the body and that the science of particular things is the foundation of all knowledge, and yet who believed in astrological medicine, wrote on oneiromancy and interpreted dreams, translated treatises on incantations, ligatures and other magic devices, and composed a book on the Tetragrammaton or ineffable name of Jehovah.[36]

That marvelous power of words—especially of the divine names of angels and of the Supreme Deity—which we may suppose Arnald to have touched upon in his Tetragrammaton, was discussed at length by a series of scholars at the close of the fifteenth and beginning of the sixteenth century whose names are most familiar to the student of those times. These men pushed the practice of allegorical interpretation of sacred writings, which had been in constant vogue among religious and theological writers from the days of the early Christian Fathers, to the extreme of discovering sublime secrets not only by regarding every incident and object in Scripture as a parable, but by treating the text itself as a cryptogram. Not only, like Isidore, did they see in every numerical measurement in the Bible mystic meaning, but in the very letters they doubted not there was hidden that knowledge by which one might gain control of all the processes of the universe; nay, penetrate through the ten sephiroth to the unspeakable and infinite source of all. For our visible universe is but the reflected image of an invisible, and each has subtle and practically unlimited power over the other. The key to that power is words. Such were the doctrines held by Pico Della Mirandola (1463-1494) who asserted that no science gave surer proof of Christ's divinity than magical and cabalistic science;[37] such were the doctrines of the renowned humanist, John Reuchlin, who connected letters in the sacred text with individual angels;[38] of Henry Cornelius Agrippa (1486-1535) who, inspired by Reuchlin's De verbe mirifico and De arte cabalistica, declared that whoever knew the true pronunciation of the name Jehovah had "the world in his mouth;"[39] of Trithemius from whom Paracelsus is said to have acquired the "Cabala of the spiritual, astral and material worlds."[40]

Moreover, the writings of men primarily devoted to science continued through the sixteenth and on into the seventeenth century to contain much the same occult theories that Michael Scot, Roger Bacon and Albertus Magnus had accepted and discussed. Jerome Cardan, one of the most prominent men of his time in mathematics and medicine—indeed, the discoverer of new processes in the former science—nevertheless believed in a strong attraction and sympathy between the heavenly bodies and our own, cast horoscopes and wrote on judicial astrology. In his Arithmetic he treated of the marvelous properties of certain numbers; in other writings he credulously discussed demons, ghosts, incantations, divination and chiromancy. His thirteen books on metoposcopy explain how to tell a person's character, ability and destiny by a minute examination of the lines on different portions of the body and by warts. He owned a selenite which he believed prevented sleep and a jacinth to which he attributed an opposite influence.[41]

The vagaries of Paracelsus are notorious, and yet he was far more than a mere quack. Tycho Brahe (1546-1601) was a faithful follower of experimental method. He saw that the science of the stars could amount to little unless based on a mass of correct observations, and was one of the first to devote his life to that foundation of patient and systematic drudgery on which the great structure of modern science is being reared. His painstaking endeavor to have accurate instruments and his care to make allowance for possible error were the marks, rare enough in those days, of the true scientist. Yet he made many an astrological prognostication, and was, as his biographer puts it, "a perfect son of the sixteenth century, believing the universe to be woven together by mysterious connecting threads which the contemplation of the stars or of the elements of nature might unravel, and thereby lift the veil of the future."[42] He also dabbled in alchemy, believed in relations of occult sympathy between "the ethereal and elementary worlds," and filled his mind with the teachings of Hermes Trismegistus, Geber, Arnald of Villanova, Raymond Lullius, Roger Bacon, Albertus Magnus, and Paracelsus.

Finally, even Francis Bacon, famed as the draughtsman of the chart which henceforth guided explorers in the domain of science, thought that there was considerable value in physiognomy and the interpretation of natural dreams, though the superstition and phantasies of later ages had debased those subjects;[43] and in divination if not "conducted by blind authority."[44] He said that by a reformed astrology one might predict plagues, famines, wars, seditions, sects, great human migrations and "all great disturbances or innovations in both natural and civil affairs."[45]

Such are the beliefs which for a long time pervaded the thought and learning of Europe; beliefs of the widespread acceptance of which we have noted but a few striking illustrations. They constitute a varied and formidable class of convictions. There was the notion that from such things as the marks upon one's body, or from one's dreams, or from peals of thunder, flight of birds, entrails of sacrificial victims and the movements of the stars, we can foretell the future. There was the assumption that certain precious stones, certain plants and trees and fountains, certain animals or parts of animals have strange and wonderful virtues. There was the idea that man, too, possesses marvelous powers to the extent that he can fascinate and bewitch his fellows. Nor should we forget the attribution to the heavenly bodies of an enormous influence over minerals and vegetation, over human health and character, over national constitutions and customs, even over religious movements. We find this notion of occult virtue extended to things without physical reality: to words, to numbers, to written characters and formulæ. It is applied to certain actions and ways of doing things: to "ligatures and suspensions," for instance. Then there was the belief that wonders may be wrought by the aid of demons, and that incantations, suffumigations, and the like are of great value in invoking spirits. Finally, there was a vague general notion that not only are the ethereal and elementary worlds joined by occult sympathy, but that all parts of the universe are somehow mystically connected, and that perhaps a single magic key may be discovered by which we may become masters of the entire universe.

How shall we classify these beliefs? What shall we call them? What is their meaning, what their origin and cause? As for classification, it is easy to suggest names which partially apply to some of these notions, or adequately characterize them individually. The art of signatures, oneiromancy, augury, divination, astrology, alchemy, the Cabala, sorcery, and necromancy are some designations which at once come to mind. But no one of them is at all adequate as a class name for all these beliefs and the practices which they involve, taken together. Are not these notions, nevertheless, closely allied; is there not an intimate relation between them all? And is not "magic" a term which will include them all and denote the general subject, the philosophy and the art, of which they all are branches?

True, many of the holders of the beliefs above enumerated declaimed against "magic."[46] But sometimes fear of being accused of magic was their very reason for so doing. Bede had such a fear when he treated of divination by thunder. Roger Bacon took suspicious care to insist that his theories had nothing to do with magic, which he declared was for the most part a mere pretense and could bring marvels to pass only by diabolical assistance.[47] The writer of the Speculum Astronomiae—probably Albertus Magnus—found it necessary to write a treatise to distinguish books of necromancy from works on "astronomy," i. e., astrology.[48] Coming to a later age, we find Agrippa frankly owning his trust in magic, and including under it, in his three books of Occult Philosophy, practically all the beliefs that we have mentioned. For him magic embraced the fields of nature, mathematics and theology. Indeed, men of his day and of the century following displayed a tendency to stretch the term to include true science. He himself called magic "the acme of all philosophy." Giovanni Battista della Porta (1540-1615), not it is true without considerable justification, called his encyclopedic work on nature Natural Magic.[49] Lord Bacon chose to understand magic "in its ancient and honorable significance" among the Persians as "a sublimer wisdom or a knowledge of universal nature." He said that as physics, investigating efficient and material causes, produced mechanics, so metaphysics, studying into forms, produced magic.[50]

Apparently, then, magic has a broad significance and a long history. The word itself takes us back to the Magi of ancient Persia; the thing it represents is older yet. It will form the theme of our next chapter, where we shall discuss its history and its meaning, and then the particular significance of those beliefs accepted by men of learning which have been enumerated in the present chapter.


  1. H. C. Lea, History of the Inquisition in the Middle Ages (1887), vol. iii, p. 437. Mr. Lea's chapter on "Sorcery and the Occult Arts" is very interesting and contains much material which it is difficult to find elsewhere.
  2. We speak of persons as jovial or saturnine or mercurial in temperament; as ill-starred, and so on.
  3. The classic on the theme of magic reputations incurred by the learned in ancient and mediæval times is Gabriel Naudé's Apologie pour tous les grands personages qui ont esté faussement soupçonnez de Magie." Paris, 1625. That such reputations were often unjustly incurred was recognized long before Naudé, however. To say nothing now of Apuleius' Apologia, to which we shall refer later, attention may be called to the fact that even William of Malmesbury, while relating with apparent credulity the legends in regard to Gerbert, had the grace to admit that "the common people often attack the reputation of the learned, and accuse any one of dealing with the devil who excels in his art" Gesta Regum Anglorum, book ii, secs. 167, 168.
  4. République, book iv, ch. 2, cited by W. E. H. Lecky, History of Rationalism (1900), vol. i, p. 28. The chapter upon "Magic and Witchcraft" contains considerable material bearing upon our theme. A similar attitude to that of Bodin is found in a political treatise of about the year 1300, probably written by Pierre du Bois, where an argument for the universal rule of a French monarch is based on astrology. N. de Wailly, Mémoire sur un opuscule anonyme (Mémoires de l'Institut Impérial de France), vol. xviii, pt. ii, p. 442.
  5. Summa Theologica, pars prima, quæst. 115, arts. 3 and 4.
  6. For some data on this point see Hastings Rashdall, The Universities of Europe in the Middle Ages (1895), vol. i, pp. 240-250; vol. ii, pp. 290, 452, 458, 459.
  7. Etymologiae, bk. viii, ch. 9. In Migne's Patrologia Latina, vol. lxxxii.
  8. Ibid., bk. xvi, passim.
  9. Ibid., bk. iii, ch. 71. He condemned astrology, however. See ibid., and bk. iii, ch. 27.
  10. "Liber Numerorum qui in Sanctis Scripturis Occurunt." (Also in Migne, vol. lxxxiii, col. 179.) "Non est superfluum numerorum causas in Scripturis sanctis attendere. Habent enim quamdam scientiae doctrinam plurimaque mystica sacramenta."
  11. De Natura Rerum, ch. 24; De Temporum Ratione, ch. 28. The scientific writing of Bede may be found in vol. vi of his works as edited by J. A. Giles. London, 1843.
  12. De Tonitruis ad Herefridum, and De Minutione Sanguinis sive Phlebotomia. Many spurious treatises were attributed to Bede but there are some reasons for believing these genuine, although they are not named by Bede in the list of his writings which he gives in his Ecclesiastical History. Giles included them in his edition after some hesitation.
  13. For the predominance of astrology in the mathematics of the 9th, 10th, 11th and 12th centuries, cf. Histoire Littéraire, vol. v, p. 183; vi, 9; vii, 137; ix, 197.
  14. De Naturis Rerum, bk. ii, ch. 173, and bk. i, ch. 7. Volume xxxiv of The Chronicles and Memorials of Great Britain. (The Rolls Series.)
  15. Ibid., bk. i, ch. 7.
  16. De Naturis Rerum, bk. ii, ch. 63.
  17. Ibid., bk. ii, ch. 80.
  18. Ibid., bk. ii, ch. 3 et seq.
  19. Ibid., bk. ii, ch. 88. In chapter 87 he writes: "Chelidonius autem rufus portantes se gratissimos facit; niger vero gestatus optimum finem negotiis imponit, et ad iras potentium sedandas idoneus est."
  20. Ibid., bk. ii, ch. 89.
  21. Ibid., bk. ii, ch. 85. "In verbis et herbis et lapidibus multam esse virtutem compertum est a diligentibus naturarum investigatoribus. Certissimum autem experimentum fidem dicto nostro facit."
  22. Preface, p. xii in vol. xxxiv of the Rolls Series.
  23. My information concerning Michael Scot is mainly derived from his biography (Edinburgh, 1897) by Rev. J. Wood Brown, who has studied the manuscript copies of Scot's works in various European libraries and has succeeded in dispelling much of the uncertainty which previously existed concerning the events of Scot's career and even the dates of his life. Of Scot's works the Physionomia exists in printed form; indeed, eighteen editions of it are said to have been issued between the years 1477 and 1660.
  24. The poem is printed in Forschungen zur Deutschen Geschichte, vol. xviii, (1878) p. 486.
  25. The part of the manuscript containing the experiment was written between 1450 and 1500, Brown thinks, but purports to be a copy "from a very ancient work." If spurious, its fabricator at least shows considerable familiarity with Scot's life. See Brown, pp. 18-19. The recipe is given in full in the appendix of Brown's book.
  26. De Secretis Operibus Artis et Naturae et de Nullitate Magiae, ch. 7. Contained in the Appendix of vol. xv of the Rolls Series, edited by J. S. Brewer, London, 1859.
  27. Opus Maius, vol. ii, pp. 204-221. Edited by J. H. Bridges, Oxford, 1897-1900. On page 210 et seq. Bacon gives an elaborate recipe for an elixir vitae.
  28. Opus Minus, Rolls Series, vol. xv, pp. 373-4.
  29. Bridges, Opus Maius, vol. i, pp. 137-139.
  30. Compendium Studii, Rolls Series, vol. xv, pp. 421-422.
  31. Bridges, Opus Maius, vol. i, pp. 253-269.
  32. De Secretis, ch. 3, discusses this question of fascination and also the power of words and of the human soul. In regard to characters and incantations, see De Secretis, ch. 2, and the Opus Tertium, which is also, contained in vol. xv of the Rolls Series, ch. 26.
  33. Opus Tertium, ch. 27.
  34. "Gaspar fert myrram, thus Melchoir, Balthasar aurum.
    Haec tria qui secum portabit nomina regum
    Solvitur a morbo Christi pietate caduco."
    Hist. Litt., vol. XXV, p. 327.
  35. See Liber Mineralium. Opera Omnia, ed. Borgnet (1890), vol. v, page 23 et seq.
  36. Two good accounts of Arnald are those in the Histoire Littéraire, vol. xxviii and Lea, History of the Inquisition, vol. iii, pp. 52-57. Older accounts are generally very misleading.
  37. J. M. Rigg, Giovanni Pico Della Mirandola, London, 1890, pp. viii-x.
  38. Janssen, History of the German People, vol. iii, p. 45, of the English translation by A. M. Christie (1900).
  39. Henry Morley, Life of Agrippa von Nettesheim (London, 1856), vol, i, p. 79. This biography includes a full and instructive outline of Agrippa's work on Occult Philosophy.
  40. A. E. Waite, Hermetical and Alchemistical Writings of Paracelsus, vol, i, p. xii.
  41. For Cardan, see the biography in two volumes by Henry Morley, London, 1854, and that in one volume by W. G. Waters, London. 1898.
  42. J. L. E. Dreyer, Tycho Brahe. A Picture of Scientific Life and Work in the Sixteenth Century (Edinburgh, 1890), p. 56. A valuable book.
  43. De Augmentis Scientiarum, bk. iv, ch. 1.
  44. Ibid., bk iv, ch. 3.
  45. Ibid., bk. iii, ch. 4.
  46. Bodin for instance condemned "magic" in his De Magorum Daemonomania (Paris, 1581).
  47. Bridges, Opus Maius, vol. i, p. 241. See too the De Secretis Operibus Artis et Naturae et de Nullitate Magiae. Rolls Series, vol. xv, appendix.
  48. Spec. Astron., ch. 17. Albertus Magnus, Opera Omnia, ed. Borgnet (1890), vol. x, pp. 629 et seq. And he finally came to the conclusion that "concerning books of necromancy the better judgment—prejudice aside—seems to be that they ought rather to be preserved than destroyed. For the time is perchance near at hand in which, for reasons which I now suppress, it will be advantageous to consult them occasionally. Nevertheless, let their inspectors abstain from abuse of them." Ch. 17.

    Similarly Roger Bacon, in his De Secretis, ch. 3, after mentioning books of magic to be eschewed, remarked that many books classed as magic were not such but contained worthy wisdom.
  49. Magiae Naturalis Libri XX. Lyons, 1651.
  50. De Augmentis, bk. iii, ch. 4.