The Age of Faith

by Will Durant

  His interest extended to nearly all the sciences. He gave the best medieval account of the Hindu numerals. He wrote treatises on the astrolabe, the planisphere, the armillary sphere; and formulated astronomical tables for Sultan Masud. He took it for granted that the earth is round, noted “the attraction of all things towards the center of the earth,” and remarked that astronomic data can be explained as well by supposing that the earth turns daily on its axis and annually around the sun, as by the reverse hypothesis.30 He speculated on the possibility that the Indus valley had been once the bottom of a sea.31 He composed an extensive lapidary, describing a great number of stones and metals from the natural, commercial, and medical points of view. He determined the specific gravity of eighteen precious stones, and laid down the principle that the specific gravity of an object corresponds to the volume of water its displaces.32 He found a method of calculating, without laborious additions, the result of the repeated doubling of a number, as in the Hindu story of the chessboard squares and the grains of sand. He contributed to geometry the solution of theorems that thereafter bore his name. He composed an encyclopedia of astronomy, a treatise on geography, and an epitome of astronomy, astrology, and mathematics. He explained the workings of natural springs and artesian wells by the hydrostatic principle of communicating vessels.33 He wrote histories of Mahmud’s reign, of Subuktigin, and of Khwarizm. Oriental historians call him “the Sheik”—as if to mean “the master of those who know.” His multifarious production in the same generation with Ibn Sina, Ibn al-Haitham, and Firdausi, marks the turn of the tenth century into the eleventh as the zenith of Islamic culture, and the climax of medieval thought.34

  Chemistry as a science was almost created by the Moslems; for in this field, where the Greeks (so far as we know) were confined to industrial experience and vague hypothesis, the Saracens introduced precise observation, controlled experiment, and careful records. They invented and named the alembic (al-anbiq), chemically analyzed innumerable substances, composed lapidaries, distinguished alkalis and acids, investigated their affinities, studied and manufactured hundreds of drugs.* Alchemy, which the Moslems inherited from Egypt, contributed to chemistry by a thousand incidental discoveries, and by its method, which was the most scientific of all medieval operations. Practically all Moslem scientists believed that all metals were ultimately of the same species, and could therefore be transmuted one into another. The aim of the alchemists was to change “base” metals like iron, copper, lead, or tin into silver or gold; the “philosopher’s stone” was a substance—ever sought, never found—which when properly treated would effect this transmutation. Blood, hair, excrement, and other materials were treated with various reagents, and were subjected to calcination, sublimation, sunlight, and fire, to see if they contained this magic al-iksir or essence.36 He who should possess this elixir would be able at will to prolong his life. The most famous of the alchemists was Jabir ibn Hayyan (702–65), known to Europe as Gebir. Son of a Kufa druggist, he practiced as a physician, but spent most of his time with alembic and crucible. The hundred or more works attributed to him were produced by unknown authors, chiefly in the tenth century; many of these anonymous works were translated into Latin, and strongly stimulated the development of European chemistry. After the tenth century the science of chemistry, like other sciences, gave ground to occultism, and did not lift its head again for almost three hundred years.

  The remains of Moslem biology in this period are scant. Abu Hanifa al-Dinawari (815–95) wrote a Book of Plants based on Dioscorides, but adding many plants to pharmacology. Mohammedan botanists knew how to produce new fruits by grafting; they combined the rose bush and the almond tree to generate rare and lovely flowers.37 Othman Amr al-Jahiz (d. 869) propounded a theory of evolution like al-Masudi’s: life had climbed “from mineral to plant, from plant to animal, from animal to man.”38 The mystic poet Jalal ud-din accepted the theory, and merely added that if this has been achieved in the past, then in the next stage men will become angels, and finally God.39

  III. MEDICINE

  Meanwhile men loved life while maligning it, and spent great sums to stave off death. The Arabs had entered Syria with only primitive medical knowledge and equipment. As wealth came, physicians of better caliber were developed in Syria and Persia, or were brought in from Greece and India. Forbidden by their religion to practice vivisection, or the dissection of human cadavers, Moslem anatomy had to content itself with Galen and the study of wounded men. Arabic medicine was weakest in surgery, strongest in medicaments and therapy. To the ancient pharmacopeia the Saracens added ambergris, camphor, cassia, cloves, mercury, senna, myrrh; and they introduced new pharmaceutical preparations—sirups (Arabic sharab), juleps (golab), rose water, etc. One of the main features of Italian trade with the Near East was the importation of Arabic drugs. The Moslems established the first apothecary shops and dispensaries, founded the first medieval school of pharmacy, and wrote great treatises on pharmacology. Moslem physicians were enthusiastic advocates of the bath, especially in fevers40 and in the form of the steam bath. Their directions for the treatment of smallpox and measles could scarcely be bettered today.41 Anesthesia by inhalation was practiced in some surgical operations;42 hashish and other drugs were used to induce deep sleep.43 We know of thirty-four hospitals established in Islam in this period,44 apparently on the model of the Persian academy and hospital at Jund-i-Shapur; in Baghdad the earliest known to us was set up under Harun al-Rashid, and five others were opened there in the tenth century; in 918 we hear of a director of hospitals in Baghdad.45 The most famous hospital in Islam was the bimaristan founded in Damascus in 706; in 978 it had a staff of twenty-four physicians. Medical instruction was given chiefly at the hospitals. No man could legally practice medicine without passing an examination and receiving a state diploma; druggists, barbers, and orthopedists were likewise subject to state regulation and inspection. The physician-vizier Ali ibn Isa organized a staff of doctors to go from place to place to tend the sick (931); certain physicians made daily visits to jails; there was an especially humane treatment of the insane. But public sanitation was in most places poorly developed; and in four centuries forty epidemics ravaged one or another country of the Moslem East.

  In 931 there were 860 licensed physicians in Baghdad.46 Fees rose with proximity to the court. Jibril ibn Bakhtisha, physician to Harun, al-Mamun, and the Barmakids, amassed a fortune of 88,800,000 dirhems ($7,104,000); we are told that he received 100,000 dirhems for bleeding the caliph twice a year, and a like sum for giving him a semiannual purgative.47 He successfully treated hysterical paralysis in a slave girl by pretending to disrobe her in public. From Jibril onward there is a succession of famous physicians in Eastern Islam: Yuhanna ibn Masawayh (777–857), who studied anatomy by dissecting apes; Hunain ibn Ishaq, the translator, author of Ten Treatises on the Eye—the oldest systematic textbook of ophthalmology; and Ali ibn Isa, greatest of Moslem oculists, whose Manual for Oculists was used as a text in Europe till the eighteenth century.

  The outstanding figure in this humane dynasty of healers was Abu Bekr Muhammad al-Razi (844–926), famous in Europe as Rhazes. Like most of the leading scientists and poets of his time, he was a Persian writing in Arabic. Born at Rayy near Tehran, he studied chemistry, alchemy, and medicine at Baghdad, and wrote some 131 books, half of them on medicine, most of them lost. His Kitab al-Hawi (Comprehensive Book) covered in twenty volumes every branch of medicine. Translated into Latin as Liber continens, it was probably the most highly respected and frequently used medical textbook in the white world for several centuries; it was one of the nine books that composed the whole library of the medical faculty at the University of Paris in 1395.48 His Treatise on Smallpox and Measles was a masterpiece of direct observation and clinical analysis; it was the first accurate study of infectious diseases, the first effort to distinguish the two ailments. We may judge its influence and repute by the forty English editions printed between 1498 and 1866. The most famous of al-Razi’s wor
ks was a ten-volume survey of medicine, the Kitab al-Mansuri (Book for al-Mansur), dedicated to a prince of Khurasan. Gerard of Cremona translated it into Latin; the ninth volume of this translation, the Nonus Almansoris, was a popular text in Europe till the sixteenth century. Al-Razi introduced new remedies like mercurial ointment, and the use of animal gut in sutures. He checked the enthusiasm for urinalysis in an age when physicians were prone to diagnose any disease by examining the urine, sometimes without seeing the patient. Some of his shorter works showed a genial side; one was “On the Fact That Even Skillful Physicians Cannot Cure All Diseases”; another was entitled, “Why Ignorant Physicians, Laymen, and Women Have More Success than Learned Medical Men.” Al-Razi was by common consent the greatest of Moslem physicians, and the greatest clinician of the Middle Ages.49 He died in poverty at the age of eighty-two.

  In the school of medicine at the University of Paris hang two portraits of Moslem physicians—“Rhazes” and “Avicenna.” Islam knew its greatest philosopher and most famous physician as Abu Ali al-Husein ibn Sina (980–1037). His autobiography—one of the few in Arabic literature—shows us how mobile might be, in medieval days, the life of a scholar or sage. Son of a money-changer of Bokhara, Avicenna was educated by private tutors, who gave a Sufi mystic turn to an otherwise scientific mind. “At the age of ten,” says Ibn Khallikan, with customary Oriental hyperbole, “he was a perfect master of the Koran and general literature, and had obtained a certain degree of information in theology, arithmetic, and algebra.”50 He studied medicine without a teacher, and while still young began to give gratis treatment. At seventeen he brought back to health the ailing ruler of Bokhara, Nuh ibn Mansur, became an official of the court, and spent eager hours in the Sultan’s voluminous library. The breakup of the Samanid power towards the end of the tenth century led Avicenna to take service under al-Mamun, prince of Khwarizm. When Mahmud of Ghazni sent for Avicenna, al-Biruni, and other intellectual lights of al-Mamun’s court, Avicenna refused to go. With a fellow scholar, Masihi, he escaped into the desert. There in a dust storm Masihi died; but Avicenna, after many hardships, reached Gurgan, and took service at the court of Qabus. Mahmud circulated throughout Persia a picture of Avicenna, and offered a reward for his capture, but Qabus protected him. When Qabus was murdered, Avicenna was called to treat the emir of Hamadan; he succeeded so well that he was made vizier. But the army did not like his rule; it seized him, pillaged his home, and proposed his death. He escaped, hid himself in the rooms of a druggist, and began in his confinement to write the books that were to make his fame. As he was planning a secret departure from Hamadan he was arrested by the emir’s son, and spent several months in jail, where he continued his writing. He again escaped, disguised himself as a Sufi mystic, and after adventures too numerous for our space found refuge and honors at the court of Ala ad-Dawla, the Buwayhid Emir of Isfahan. A circle of scientists and philosophers gathered about him, and held learned conferences over which the emir liked to preside. Some stories suggest that the philosopher enjoyed the pleasures of love as well as of scholarship; on the other hand we get reports of him as absorbed day and night in study, teaching, and public affairs; and Ibn Khallikan quotes from him some unhackneyed counsel: “Take one meal a day…. Preserve the seminal fluid with care; it is the water of life, to be poured into the womb.”51 Worn out too soon, he died at fifty-seven on a journey to Hamadan, where to this day pious veneration guards his grave.

  Amid these vicissitudes he found time, in office or in jail, in Persian or in Arabic, to write a hundred books, covering nearly every field of science and philosophy. For good measure he composed excellent poems, of which fifteen survive; one of them slipped into the Rubaiyat of Omar Khayyam; another, “The Descent of the Soul” (into the body from a higher sphere), is still memorized by young students in the Moslem East. He translated Euclid, made astronomical observations, and devised an instrument like our vernier. He made original studies of motion, force, vacuum, light, heat, and specific gravity. His treatise on minerals was a main source of European geology until the thirteenth century. His remarks on the formation of mountains is a model of clarity:

  Mountains may be due to two different causes. Either they result from upheavals of the earth’s crust, such as might occur in violent earthquake; or they are the effect of water, which, cutting for itself a new route, has denuded the valleys. The strata are of different kinds, some soft, some hard; the winds and waters disintegrate the first kind, but leave the other intact. It would require a long period of time for all such changes to be accomplished … but that water has been the main cause of these effects is proved by the existence of fossil remains of aquatic animals on many mountains.52

  Two gigantic productions contain Avicenna’s teaching: the Kitab al-Shifa, or Book of Healing (of the soul), an eighteen-volume encyclopedia of mathematics, physics, metaphysics, theology, economics, politics, and music; and the Qanun-fi-l-Tibb, or Canon of Medicine, a gigantic survey of physiology, hygiene, therapy, and pharmacology, with sundry excursions into philosophy. The Qanun is well organized, and has moments of eloquence; but its scholastic passion for classification and distinction becomes the one disease for which the author has no prescription. He begins with a discouraging admonition: “Every follower of my teachings who wishes to use them profitably should memorize most of this work,”52a which contains a million words. He conceives medicine as the art of removing an impediment to the normal functioning of nature. He deals first with the major diseases—their symptoms, diagnosis, and treatment; he has chapters on general and individual prophylaxis and hygiene, and on therapy through enemas, bleeding, cautery, baths, and massage. He recommends deep breathing, even occasional shouting, to develop the lungs, chest—and uvula. Book II summarizes Greek and Arabic knowledge of medicinal plants. Book III, on special pathology, contains excellent discussions of pleurisy, empyema, intestinal disorders, sexual diseases, perversions, and nervous ailments, including love. Book IV discusses fevers, surgery, and cosmetics, the care of the hair and the skin. Book V—materia medica—gives detailed directions for concocting 760 drugs. The Qanun, translated into Latin in the twelfth century, dethroned al-Razi, and even Galen, as the chief text in European medical schools; it held its place as required reading in the universities of Montpellier and Louvain till the middle of the seventeenth century.

  Avicenna was the greatest writer on medicine, al-Razi the greatest physician, al-Biruni the greatest geographer, al-Haitham the greatest optician, Jabir probably the greatest chemist, of the Middle Ages; these five names, so little known in present-day Christendom, are one measure of our provincialism in viewing medieval history. Arabic, like all medieval science, was often sullied with occultism; except in optics it excelled rather in the synthesis of accumulated results than in original findings or systematic research; at the same time, however haltingly, it developed in alchemy that experimental method which is the greatest pride and tool of the modern mind. When Roger Bacon proclaimed that method to Europe, five hundred years after Jabir, he owed his illumination to the Moors of Spain, whose light had come from the Moslem East.

  IV. PHILOSOPHY

  In philosophy, as in science, Islam borrowed from Christian Syria the legacy of pagan Greece, and returned it through Moslem Spain to Christian Europe. Many influences, of course, ran together to produce the intellectual rebellion of the Mutazilites, and the philosophies of al-Kindi, al-Farabi, Avicenna, and Averroës. Hindu speculations came in through Ghazni and Persia; Zoroastrian and Jewish eschatology played some minor role; and Christian heretics had stirred the air of the Near East with debate on the attributes of God, the nature of Christ and the Logos, predestination and free will, revelation and reason. But the yeast that caused the ferment of thought in Moslem Asia—as in Renaissance Italy—was the rediscovery of Greece. Here, through however imperfect translations of apocryphal texts, a new world appeared: one in which men had reasoned fearlessly about everything, unchecked by sacred scriptures, and had conceived a cosmos not o
f divine whimsy and incalculable miracle, but of majestic and omnipresent law. Greek logic, fully conveyed through Aristotle’s Organon, came like an intoxication to Moslems now gifted with leisure to think; here were the terms and implements they needed for thought; now for three centuries Islam played the new game of logic, drunk like the Athenian youth of Plato’s time with the “dear delight” of philosophy. Soon the whole edifice of Mohammedan dogma began to tremble and crack, as Greek orthodoxy had melted under the Sophists’ eloquence, as Christian orthodoxy would wince and wilt under the blows of the Encyclopedists and the whips of Voltaire’s wit.