VII. ROGER BACON: C. 1214–92

The most famous of medieval scientists was born in Somerset about 1214. We know that he lived till 1292, and that in 1267 he called himself an old man.96 He studied at Oxford under Grosseteste, and caught from the great polymath a fascination for science; already in that circle of Oxford Franciscans the English spirit of empiricism and utilitarianism was taking form. He went to Paris about 1240, but did not find there the stimulation that Oxford had given him; he marveled that so few Parisian professors knew any learned language besides Latin, that they gave so little time to science, and so much to logical and metaphysical disputes that seemed to Bacon criminally useless for life. He “majored” in medicine, and began to write a treatise on the relief of old age. To get data he visited Italy, studied Greek in Magna Graecia, and there became acquainted with some works of Moslem medicine. In 1251 he returned to Oxford, and joined the teaching staff. He wrote in 1267 that in the preceding twenty years he had spent “more than £2000 in the purchase of secret books and instruments,” and in training young men in languages and mathematics.97 He engaged Jews to teach him and his students Hebrew, and to help him read the Old Testament in the original. About 1253 he entered the Franciscan Order, but he seems never to have become a priest.

Sick of the metaphysics of the schools, Bacon gave himself with passion to mathematics, natural science, and philology. We must not think of him as a lone originator, a scientific voice crying out in the scholastic wilderness. In every field he was indebted to his predecessors, and his originality was the forceful summation of a long development. Alexander Neckham, Bartholomew the Englishman, Robert Grosseteste, and Adam Marsh had established a scientific tradition at Oxford; Bacon inherited it, and proclaimed it to the world. He acknowledged his indebtedness, and gave his predecessors unmeasured praise. He recognized also his debt—and the debt of Christendom—to Islamic science and philosophy, and through these to the Greeks, and suggested that the “heathen” savants of Greece and Islam had also, in their own fashion, been inspired and guided by God.98 He had a high regard for Isaac Israeli, Ibn Gabirol, and other Hebrew thinkers, and had the courage to say a good word for the Jews who lived in Palestine at the time of the crucifixion of Christ.99 He learned avidly not only from learned men, but from any man whose practical knowledge in handicraft or husbandry could augment his store. He writes with unwonted humility:

It is certain that never, before God is seen face to face, shall a man know anything with final certainty…. For no one is so learned in nature that he knows all… the nature and properties of a single fly…. And since, in comparison with what a man knows, those things of which he is ignorant are infinite, and beyond comparison greater and more beautiful, he is out of his mind who extols himself in regard to his own knowledge…. The wiser men are, the more humbly they are disposed to receive the instruction of another, nor do they disdain the simplicity of the teacher, but behave humbly toward peasants, old women, and children, since many things are known to the simple and unlearned which escape the notice of the wise…. I have learned more important truths from men of humble station than from all the famous doctors. Let no man, therefore, boast of his wisdom.100

He labored with such fervor and haste that in 1256 his health broke down; he retired from university life, and for ten years we lose track of him. Probably in this period he composed some of his minor works—De speculis comburentibus (On Burning Glasses), De mirabili potestate artis et naturae (On the Marvelous Power of Invention and Nature), and Computus naturalium (Computation of Natural Events). Now also he planned his “Principal Work”—Scriptum principale, a one-man encyclopedia to be in four volumes: (1) grammar and logic; (2) mathematics, astronomy, and music; (3) natural science—optics, geography, astrology, alchemy, agriculture, medicine, and experimental science; and (4) metaphysics and morals.

He had written some scattered portions when what seemed a stroke of good fortune interrupted his program. In February, 1265, Guy Foulques, Archbishop of Narbonne, became Pope Clement IV, and carried into the papacy something of the liberal spirit that had developed in southern France from the mingling of peoples and creeds. In June he wrote to Bacon bidding him send a “fair copy” of his works, “secretly and without delay,” and “notwithstanding the prohibition of any prelate, or any constitution of thy Order.”101Bacon set himself feverishly (as may be seen from the passion of his style) to finish his encyclopedia; then, in 1267, fearing that Clement might die or lose interest before its completion, he put it aside, and composed in twelve months—or put together from his manuscripts—the preliminary treatise which we known as the Opus maius, or Larger Work. Suspecting that even this would prove too long for a busy Pope, he wrote a synopsis of it, an Opus minus, or Smaller Work. Early in 1268 he sent these two manuscripts to Clement, with an essay De multiplicatione specierum (On the Multiplication of Vision). Worried lest these be lost in transit, he composed still another summary of his ideas, an Opus tertium, and sent it to Clement by special messenger, together with a lens with which, he suggested, the Pope might himself make experiments. Clement died in November, 1268. So far as we know, no word of acknowledgment from him or his successors ever reached the eager philosopher.

The Opus maius, therefore, is now for us literally his “major work,” though in his intention it was but a prelude. It is substantial enough. Its 800 pages are divided into seven treatises: (1) on ignorance and error; (2) the relations between philosophy and theology; (3) the study of foreign languages; (4) the usefulness of mathematics; (5) perspective and optics; (6) experimental science; (7) moral philosophy. The book contains its due quota of nonsense, and many digressions, and too many extensive quotations from other authors; but it is written with vigor, directness, and sincerity, and is more readable today than any other work of medieval science or philosophy. Its excited disorder, its adulation of the papacy, its anxious professions of orthodoxy, its reduction of science and philosophy to the role of servants to theology, are understandable in a book of such scope and subject, written in hasty summary, and designed to win papal support for scientific education and research. For. Roger, like Francis, Bacon felt that the advancement of learning would need the aid and money of prelates and magnates for books, instruments, records, laboratories, experiments, and personnel.

As if anticipating the “idols” denounced by his namesake three centuries later, Roger begins by listing four causes of human error: the “example of frail and unworthy authority, long-established custom, the sense of the ignorant crowd, and the hiding of one’s ignorance under the show of wisdom.”102 He takes care to add that he is “in no way speaking of that solid and sure authority which… has been bestowed upon the Church.” He regrets the readiness of his time to consider a proposition proved if it can be found in Aristotle, and declares that if he had the power he would burn all the books of the Philosopher as a fountain of error and a stream of ignorance;103 after which he quotes Aristotle on every second page.

“After the four causes of error have been banished to the lower regions,” he writes at the outset of Part II, “I wish to show that there is one wisdom which is perfect, and that this is contained in the Scriptures.” If the Greek philosophers enjoyed a sort of secondary inspiration, it was because they read the books of the prophets and patriarchs.104 Bacon apparently accepts the Biblical story with simple faith, and wonders why God no longer allows men to live 600 years.105 He believes in the approaching advent of Christ and end of the world. He pleads for science as revealing the Creator in the creation, and as enabling Christians to convert heathens immune to Scripture. So “the human mind can be influenced to accept the truth of the Virgin Birth, because certain animals in a state of virginity conceive and bear young, as for example vultures and apes, as Ambrose states in the Hexaemeron. Moreover, mares in many regions conceive by virtue of the winds alone, when they desire the male, as Pliny states”106—unlucky instances of trust in authority.

In Part III Bacon labors to teach the Pope Hebrew. The study of languages is necessary to theology, philosophy, and science, for no translation conveys the precise sense of the Scriptures or the heathen philosophers. In the Opus minus Bacon gives a remarkably learned account of the various translations of the Bible, and shows an intimate acquaintance with the Hebrew and Greek texts. He proposes that the Pope appoint a committee of scholars learned in Hebrew, Greek, and Latin to revise the Vulgate, and that this revised version—and no longer the Sentences of Peter Lombard-be made the main study in theology. He urges the establishment of university professorships in Hebrew, Greek, Arabic, and Chaldean. He denounces the use of force in converting non-Christians, and asks how the Church can deal with Greek, Armenian, Syrian, Chaldean Christians except through their own languages. In this field Bacon labored as well as preached; he was the first scholar in Western Christendom to complete a Greek grammar for Latin use, and the first Christian to compose a Hebrew grammar. He claimed ability to write Greek and Hebrew, and seems also to have studied Arabic.107

When Bacon reaches the subject of mathematics his pages become eloquent with enthusiasm, then recondite with theorems. “Next to languages I hold mathematics necessary.” He makes his usual obeisance to theology: mathematics “should aid us in ascertaining the position of paradise and hell,” promote our knowledge of Biblical geography and sacred chronology, and enable the Church to correct the calendar;108 and observe, he says, how “the first proposition of Euclid”—constructing an equilateral triangle on a given line—helps us to “perceive that if the person of God the Father be granted, a Trinity of equal persons presents itself.”109 From this sublimity he proceeds to a remarkable anticipation of modern mathematical physics, by insisting that though science must use experiment as its method, it does not become fully scientific until it can reduce its conclusions to mathematical form. All nonspiritual phenomena are the product of matter and force; all forces act uniformly and regularly, and may consequently be expressed by lines and figures; “it is necessary to verify the matter by demonstrations set forth in geometrical lines”; ultimately all natural science is mathematics.110

But though mathematics is the result, experiment must be the means and test of science. Whereas the Scholastic philosophers from Abélard to Thomas had put their trust in logic, and had made Aristotle almost a member of the Trinity, veritably a holy ghost, Bacon formulates a scientific revolution in terms of mathematics and experiment. The most rigorous conclusions of logic leave us uncertain until they are confirmed by experience; only a burn really convinces us that fire burns. “He who wishes to rejoice without doubt with regard to the truths underlying phenomena must know how to devote himself to experiment.”111 At times he seems to think of experimentum not as a method of research but as a final mode of proof through putting ideas—reached by experience or reasoning—to test by constructing on their basis things of practical utility.112 More clearly than Francis Bacon, he perceives and declares that in natural science experiment is the only proof. He did not pretend that this idea was new; Aristotle, Hero, Galen, Ptolemy, the Moslems, Adelard, Petrus Hispanus, Robert Grosseteste, Albertus Magnus, and others had made or lauded experiments. Roger Bacon made the implicit explicit, and planted the flag of science firmly on the conquered ground.

Except in optics and calendar reform, Roger, like Francis, Bacon made only negligible contributions to science itself; they were philosophers of science rather than scientists. Continuing the work of Grosseteste and others, Roger concluded that the Julian calendar exaggerated the length of the solar year by one day every 125 years—the most accurate computation theretofore made—and that the calendar, in 1267, was ten days ahead of the sun. He proposed that a day be dropped from the Julian calendar every 125 years. Almost as brilliant were the hundred pages on geography in Part IV of the Opus maius. Bacon talked eagerly with William of Rubruquis on the return of his fellow Franciscan from the Orient, learned much from him about the Orient, and was impressed by William’s account of the unnumbered millions who had never heard of Christianity. Starting from statements in Aristotle and Seneca, he remarked that “the sea between the end of Spain on the west and the beginning of India on the east is navigable in a very few days if the wind is favorable.”113 This passage, copied in the Imago mundi (1480) of Cardinal Pierre d’Ailly, was cited by Columbus in a letter to Ferdinand and Isabella in 1498 as one of the suggestions that had inspired his voyage of 1492.114

Bacon’s work in physics is a vision of modern inventions, colored now and then with the popular ideas of his time. Here, in literal translation, are the famous passages in which he leaps from the thirteenth to the twentieth century:

A fifth part of experimental science concerns the fabrication of instruments of wonderfully excellent usefulness, such as machines for flying, or for moving in vehicles without animals and yet with incomparable speed, or of navigating without oarsmen more swiftly than would be thought possible through the hands of men. For these things have been done in our day, lest anyone should ridicule them or be astonished. And this part teaches how to make instruments by which incredible weights can be raised or lowered without difficulty or labor…,115 Flying machines can be made, and a man sitting in the middle of the machine may revolve some ingenious device by which artificial wings may beat the air in the manner of a flying bird…. Also machines can be made for walking in the sea and the rivers, even to the bottom, without danger.116

A passage in the Opus maius (vi, 12) has been interpreted as referring to gunpowder:

Important arts have been discovered against foes of the state, so that without a sword or any weapon requiring physical contact they could destroy all who offer resistance…. From the force of the salt called saltpeter so horrible a sound is produced at the bursting of so small a thing, namely, a small piece of parchment, that… it exceeds the roar of sharp thunder, and the flash exceeds the greatest brilliancy of the lightning accompanying the thunder.

In a possibly interpolated passage of the Opus tertium Bacon adds that certain toys, “crackers,” are already in use, containing a mixture of saltpeter (41.2%), charcoal (29.4%), and sulphur (29.4%);117 and he suggests that the explosive power of the powder can be increased by enclosing it in solid material. He does not claim to have invented gunpowder; he was merely one of the first to study its chemistry and foresee its possibilities.

The best work of Bacon is Part V of the Opus maius, “On Perspectival Science,” and in the supplementary treatise On the Multiplication of Vision. This brilliant essay on optics stemmed from Grosseteste’s work on the rainbow, from Witelo’s adaptation of al-Haitham, and from the tradition of optical studies mounting through Avicenna, al-Kindi, and Ptolemy to Euclid (300 B.C.), who had ingeniously applied geometry to the movements of light. Is light an emanation of particles from the object seen, or is it a movement of some medium between the object and the eye? Bacon believed that every physical thing radiates force in all directions, and that these rays may penetrate solid objects:

No substance is so dense as altogether to prevent rays from passing. Matter is common to all things, and thus there is no substance on which the actions involved in the passage of a ray may not produce a change…. Rays of heat and sound penetrate through the walls of a vessel of gold or brass. It is said by Boethius that a lynx’s eye will pierce thick walls.118

We are not so sure of the lynx, but otherwise we must applaud the bold fancy of the philosopher, “of imagination all compact.” Experimenting with lenses and mirrors, Bacon sought to formulate the laws of refraction, reflection, magnification, and microscopy. Recalling the power of a convex lens to concentrate many rays of the sun at one burning point, and to spread the rays beyond that point to form a magnified image, he wrote:

We can so shape transparent bodies [lenses], and arrange them in such a way with respect to our sight and the objects of vision, that the rays will be refracted and bent in any direction we desire; and under any angle we wish we shall see the object near or at a distance. Thus from an incredible distance we might read the smallest letters, and number grains of dust or sand…. Thus a small army might appear very large and… close at hand…. So also we might cause the sun, moon, and stars in appearance to descend here below,… and many similar phenomena, so that the mind of a man ignorant of the truth could not endure them….119 The heavens might be portrayed in all their length and breadth on a corporeal figure moving with their diurnal motion; and this would be worth a whole kingdom to a wise man…. An infinite number of other marvels could be set forth.120

These are brilliant passages. Almost every element in their theory can be found before Bacon, and above all in al-Haitham; but here the material was brought together in a practical and revolutionary vision that in time transformed the world. It was these passages that led Leonard Digges (d. c. 1571) to formulate the theory on which the telescope was invented.121

But what if the progress of physical science gives man more power without improving his purposes? Perhaps the profoundest of Bacon’s insights is his anticipation of a problem that has become clear only in our time. In the concluding treatise of the Opus maiushe expresses the conviction that man cannot be saved by science alone.

All these foregoing sciences are speculative. There is, indeed, in every science a practical side…. But only of moral philosophy can it be said that it is… essentially practical, for it deals with human conduct, with virtue and vice, with happiness and misery…. All other sciences are of no account except as they help forward right action. In this sense “practical” sciences, such as experiment, chemistry (alkimia), and the rest, are seen to be speculative in reference to the operations with which moral or political science is concerned. This science of morality is the mistress of every department of philosophy.122

Bacon’s final word is not for science but for religion; only by a morality supported by religion can man save himself. But which religion should it be? He tells of the parliament of religions—Buddhist, Mohammedan, Christian—which William of Rubruquis reported to have been held at Karakorum at the suggestion and under the presidency of Mangu Khan.123 He compares the three religions, and concludes in favor of Christianity, but with no merely theological conception of its function in the world. He felt that the papacy, despite Grosseteste’s criticisms, was the moral bond of a Europe that without it would be a chaos of clashing faiths and arms; and he aspired to strengthen the Church with science, languages, and philosophy for her better spiritual government of the world.124He ended his book as he had begun it, with a warm profession of fidelity to the Church, and concluded with a glorification of the Eucharist—as if to say that unless man seeks periodical communion with his highest ideal he will be lost in the conflagration of the world.

Perhaps the failure of the popes to respond in any way to Bacon’s program and appeals darkened his spirit and embittered his pen. In 1271 he published an unfinished Compendium studii philosophiae, which contributed little to philosophy, but much to the odium theologicum that was disordering the schools. He settled summarily the subsiding debate between realism and nominalism: “a universal is nothing but the similarity of several individuals,” and “one individual has more reality than all universals put together.”125He adopted Augustine’s doctrine of rationes seminales, and arrived at a view in which the efforts of all things to better themselves engendered a long series of developments.126 He accepted the Aristotelian notion of an Active Intellect or Cosmic Intelligence “flowing into our minds and illuminating them,” and came dangerously near to Averroistic pantheism.127

But what shocked his time was not his philosophical ideas so much as his attacks upon his rivals and the morals of the age. In the Compendium philosophiae almost every phase of thirteenth-century life felt his lash: the disorder of the papal court, the degeneration of the monastic orders, the ignorance of the clergy, the dullness of sermons, the misconduct of students, the sins of the universities, the windy verbiage of the philosophers. In a Tractatus de erroribus medicorum he listed “thirty-six great and radical defects” in the medical theory and practice of his time. In 1271 he wrote a passage that may incline us to take with better grace the shortcomings of our age:

More sins reign in these days than in any past age… the Holy See is torn by the deceit and fraud of unjust men…. Pride reigns, covetousness burns, envy gnaws upon all; the whole Curia is disgraced with lechery, and gluttony is lord of all…. If this be so in the Head, what then is done among the members? Let us see the prelates, how they run after money, neglect the care of souls, promote their nephews and other carnal friends, and crafty lawyers who ruin all by their counsel…. Let us consider the Religious Orders; I exclude none from what I say; see how far they are fallen, one and all, from their right state; and the new Orders [the Friars] are already horribly decayed from their original dignity. The whole clergy is intent upon pride, lechery, and avarice; and wheresoever clerks [students] are gathered together … they scandalize the laity with their wars and quarrels and other vices. Princes and barons and knights oppress one another, and trouble their subjects with infinite wars and exactions…. The people, harassed by their princes, hate them, and keep no fealty save under compulsion; corrupted by the evil example of their betters, they oppress and circumvent and defraud one another, as we see everywhere with our eyes; and they are utterly given over to lechery and gluttony, and are more debased than tongue can tell. Of merchants and craftsmen there is no question, since fraud and deceit and guile reign beyond all measure in their words and deeds…. The ancient philosophers, though without that quickening grace which makes men worthy of eternal life, lived beyond all comparison better than we, both in decency and in contempt of the world with all its delights and riches and honors, as all men may read in the works of Aristotle, Seneca, Tully, Avicenna, al-Farabi, Plato, Socrates, and others; and so it was that they attained to the secrets of wisdom and found out all knowledge. But we Christians have discovered nothing worthy of those philosophers, nor can we even understand their wisdom; which ignorance of ours springs from this cause, that our morals are worse than theirs…. There is no doubt whatever among wise men but that the Church must be purged.128

He was not impressed by his contemporaries in philosophy; not one of them, he wrote to Clement IV, could in ten years write such a book as the Opus maius; their tomes seemed to Bacon a mass of voluminous superfluity and “ineffable falsity”;129 and the whole structure of their thought rested upon a Bible and an Aristotle mistranslated and misunderstood.130 He ridiculed Thomas’ long discussion of the habits, powers, intelligence, and movements of the angels.131

Such an exaggerated indictment of European life, morals, and thought in a brilliant century must have left Bacon alone against the world. Nevertheless there is no evidence that his Order or the Church persecuted him, or interfered with his freedom of thought or utterance, before 1277—i.e., six years after the issuance of the above Jeremiad. But in that year John of Vercelli, head of the Dominicans, and Jerome of Ascoli, head of the Franciscans, conferred to allay certain quarrels that had arisen between the two orders. They agreed that the friars of each order should abstain from criticizing the other, and that “any friar who was found by word or deed to have offended a friar of the other order should receive from his provincial such punishment as ought to satisfy the offended brother.”132Shortly thereafter Jerome, according to the fourteenth-century Franciscan Chronicle of the XXIV Generals of the Order, “acting on the advice of many friars, condemned and reprobated the teaching of Friar Roger Bacon, master of sacred theology, as containing some suspected novelties, on account of which the same Roger was condemned to prison.”133 We have no further knowledge of the matter. Whether the “novelties” were heresies, or reflected a suspicion that he dabbled in magic, or covered up a decision to silence a critic offensive to Dominicans and Franciscans alike, we cannot say. Nor do we know how severe were the conditions of Bacon’s imprisonment, nor how long it lasted. We are told that in 1292 certain prisoners condemned in 1277 were freed. Presumably Bacon was released then or before, for in 1292 he published a Compendium studii theologiae. Thereafter we have only an entry in an old chronicle: “The noble doctor Roger Bacon was buried at the Grey Friars” (the Franciscan church) “in Oxford in the year 1292.”134

He had little influence on his time. He was remembered chiefly as a man of many marvels, a magician and conjurer; it was as such that he was presented in a play by Robert Greene 300 years after his death. It is hard to say how much Francis Bacon (1561–1626) owed to him; we can only note that the second Bacon, like the first, rejected Aristotelian logic and Scholastic method, questioned authority, custom, and other “idols” of traditional thought, praised science, listed its expected inventions, charted its program, stressed its practical utility, and sought financial aid for scientific research. Slowly, from that sixteenth century, Roger Bacon’s fame grew, until he became a legend—the supposed inventor of gunpowder, the heroic freethinker, the lifelong victim of religious persecution, the great initiator of modern thought. Today the pendulum returns. Historians point out that he had only a confused idea of experiment; that he did little experimenting himself; that in theology he was more orthodox than the pope; that his pages were peppered with superstitions, magic, misquotations, false charges, and legends taken for history.

It is true. It is also true that though he made few experiments he helped to state their principle and to prepare their coming; and that his protestations of orthodoxy may have been the diplomacy of a man seeking papal support for suspected sciences. His errors were the infection of his time or the haste of a spirit too eager to take all knowledge for its province; his self-praise was the balm of genius ignored; his denunciations the wrath of a frustrated Titan helplessly witnessing the submergence of his noblest dreams in an ocean of ignorance. His attack on authority in philosophy and science opened the way to wider and freer thought; his emphasis on the mathematical basis and goal of science was half a millennium ahead of his age; his warning against subordinating morality to science is a lesson for tomorrow. With all its faults and sins, his Opus maius deserves its name as a work greater than any other in all the literature of its amazing century.

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