Science in Christian Perspective



The Guide for the Perplexed
An Unforeseen Overture to Science in Twelfth-Century Cairo 

Richard P. Aulie*

3117 W. Sunnyside #1
Chicago, IL 60625

From: Perspectives on Science and Christian Faith 50 (June 1998): 122-134.

Without the Judaeo-Christian-Islamic doctrine of creation, there could have been no modern science; without creatio ex nihilo, no theory of biological evolution. Aristotle taught that the world was eternal and had no beginning. The ancient Greeks did notˇand could notˇconceive the idea that species had an origin. It was the achievement of the Middle Ages to settle the question of whether the world was eternal or had a beginning. This article is an account of Maimonides' contribution to that achievement.

It was a Spanish emigr╚, dwelling safely in Cairo and far from his Andalusian heritage, who in the last decade of the twelfth century expressed the great issue of the age:

According to Aristotle everything besides that Being is the necessary result of the latter; whilst, according to our opinion, that Being created the whole Universe with design and will, so that the Universe which had not been in existence before has by His will come into existence.2

Thus did the celebrated Jewish thinker, Moses Maimonides, set before people of all faiths the fundamental distinction between monotheism and Aristotelianism. The tranquil and disinterested reasoning of his works belies the shocks and turmoil that came his way to mold his character. Abu-'Imran Musa ibn Maymun rose above the storms of life to be sought out in Arab society throughout the Mediterranean world for his erudition in law, medicine, philosophy, and theology; and to be acclaimed by the affectionate title of "Rambam," Rabbi Moses ben Maimon. Christian philosophy of the Latin West became a commentary on his pioneering ruminations on faith and reason; his writings were a bridge between Christianity and Islam. To this day he remains one of the most influential sages Judaism has ever produced.

Among the treasures of thought that Maimonides bequeathed to the West, not least, surely, are his magisterial commentaries on Aristotelian cosmology and the will of God. Modern science, of course, could never have arisen if, as Aristotle had said, the world were eternal. In the Rambam's denial of eternality and affirmation of creation, we find a twelfth-century step toward the origin of modern science.

A Time of Wandering

Moses Maimonides was born on March 30, 1135 in the brilliant city of Cordova, in the Andalusian region of Spain.3 For eight generations his forebears had served as rabbis in the thriving Jewish community which shared with Christians and Muslims in the self-confidence and prosperity produced by the Spanish Umayyads.4 His family was accustomed to culture, learning, the practice of law, and success; the elder Maimon was an esteemed rabbinical judge.

As a boy, Moses probably wandered about the jasper halls and the forest of stately columns that can be admired today in the sanctuary of the Great Mosque in Cordoba, built in 787 by the Caliph Abd-al-Rahman I, who founded the Umayyad Caliphate in the West.5 Following the reign of the tolerant Umayyads, the incoming Almoravid dynasty was short-lived, but brought the first of the persecutions that presaged the decline of western Islam and the inevitable eclipse of Spain.6

Scholarship Amidst Persecution

Maimonides was thirteen years old when the fanatical Almohades conquered the Almoravids and captured Cordova. Christians and Jews were given the choice of conversion to Islam, exile, or death. For some eight to ten years, the Maimon family wandered across the Spanish countryside. But the locusts did not eat those years. Young Moses wrote two essays that displayed his growing prowess in scholarship: an essay on logic, written when he was the ripe age of sixteen, meant that he was studying Aristotle; and an essay on the Jewish calendar, showing his grasp of Ptolemaic and Arab astronomy, which he finished at age twenty-three.7

Fearing forced apostasy, the elder Maimon emigrated with his family to the city of Fez, which nestles today in a narrow valley in the Atlas Mountains of northern Morocco. For several centuries, a Jewish community had flourished in Fez.8 There the young Maimon continued the study of medicine.9

In 1165 the Maimon family took ship, joining the migration of Jews from the Muslim West along the Atlantic seaboard to the more tolerant Muslim East.10 Landing at Accre, they visited Jerusalem and Hebron to give thanks, and to seek a new home. But the Latin Kingdom of Jerusalem was not a promising haven; Jews were few in number, and still vivid was the collective memory of the horrible massacre of Jews and Muslims by the Crusaders in 1099.11 After a sojourn in Alexandria, the family joined the vigorous Jewish community residing in al-Fustat, which was the old city of Cairo, and where dwelt some one thousand Jewish families.12

Sanctuary at Cairo

The Maimons arrived during the final days of the brilliant Fatimid dynasty, which for two centuries had ruled Palestine, Egypt, and North Africa, and which pointed Egypt to her present ascendancy.13 Exhausted by calamities and uprootings, the elder Maimon died soon after arriving in Egypt. He had kept his family together when his Andalusian world was collapsing in ruins about him.

At age thirty-three, and only three years after departing Fez, Maimon finished the ten-year project of writing his Commentary on the Mishnah in Arabic, on Jewish laws and traditions.14 Jewish prospects brightened considerably in 1171 when Salah-al-Din ibn Ayyub, known as Saladin, the Lion of Islam, overthrew the Fatimids and brought 'Abassid supremacy to Egypt.15 The next year Maimonides wrote his Epistle to Yemen in which he reassured the Jews of Yemen in the faith of Judaism.16

Moses continued to practice medicine for his livelihood. Further medical duties quite likely came his way during the construction of the Citadel, commenced by Saladin in 1176, which stands today on the Mokattam heights overlooking Cairo.17 In the same year, Moses completed another ten-year project, the writing of Mishneh Torah in Hebrew, or the Code of Maimonides. This is his complete code of oral and written Jewish law, which he based on the whole of rabbinical literature, and which embellished the growing fame and legal authority of the sage of Fustat.18

All these accomplishments were only the prologue, as it were, for his final masterpiece which he began in about the year 1185 at the age of fifty.

Religion Versus Culture

 In Kroch and Brentano's bookstore in Chicago in 1984, I purchased my copy of The Guide For The Perplexed, a Dover 1956 reprint of the Friedlönder edition of 1881. The Guide is found in bookstores today because Maimonides wrote this work not for specialists, but for the person "whose studies have brought him into collision with religion."19 In his day the collision was occurring between Aristotelianism and monotheism. For the learned Jew, this meant that the religious values of Judaism were being challenged by the worldview emanating from Greek philosophy and science, and by the Islamic interpretation of that worldview. He wished therefore to enlighten those who, while seeking to harmonize the principles of their own religion with the cultural values of society, had become lost in perplexity and anxiety. Hence the sense of immediacy for our dayˇhe was addressing secularism and the life of faith.

Style of the Guide

The Guide is written in a direct, personal, and almost conversational styleˇanother reason for its accessibility today. In fact, Maimonides wrote it for a student of his, Joseph ibn Aknin, who was born in Morocco in about 1160 and who was possessed of a commodity rare in any epoch, "a thirst for knowledge."20 Perplexed as he was about philosophy and theology, ibn Aknin came to Cairo in order to study under the Rambam's direction.

Ibn Aknin's teacher, having guided him through a curriculum of biblical studies, Greek and Arab science and mathematics, and Islamic theology, and in order to assuage his perplexity, composed the Guide for him and others like him.21 When ibn Aknin left Cairo to settle in Aleppo, Maimonides continued to teach him by means of a kind of correspondence course. As each chapter was finished, he explained, he mailed it to his student.22 This meant that in the next five years or so ibn Aknin received a total of some one hundred eighty-three chapters in letter form, all written in Maimon's spare time.

The Meaning of "God" and "Nature"

Ibn Aknin was perplexed about passages in the Bible (the Old Testament) that seemed to conflict with Aristotelian thought concerning the doctrine of creation and the nature and attributes of God. What sharpened his perplexity were the answers given to his questions by the Islamic theologians and philosophers.

Maimonides was happy to oblige. Although he remained a staunch Aristotelian, he developed a strong case for creatio ex nihilo, not because he thought the Bible explicitly taught this doctrine, for on the contrary, he maintained that various biblical passages were entirely consistent with Aristotelian eternality as well, but simply because the reasons for creatio ex nihilo were, in his view, far better.23 Islamic theology, called the "Kalam," meaning speech or scholastic theology, might seem to have been congenial to Judaism with respect to the doctrine of creation, and to the attributes, existence, and incorporeality of God. After all, Islam was monotheistic, was based on revelation, and had strong historical roots in Judaism. Nevertheless he opposed the Kalam, and left no doubt among his Muslim readers that he stood for Judaism.24

A belief in the incorporeality of God was required by a belief in the absolute oneness of God, which Maimonides took care to distinguish from the "unity" of God.25 Incorporeality implied creation and providence, and also God's will, perception, and knowledge; all of which, he readily acknowledged, were difficult problems.26 Step by step he showed that, in forming a mature understanding of the incorporeal nature of God, the seeker need not choose between faith and reason, and indeed a choice was not possible.27 The twentieth-century Christian student of the Bible can reap nothing but profit from consulting his myriad interpretations of Old Testament passages.

Attributes and Essence

 It was actually the doctrine of transcendence, not incorporeality per se, to which Maimonides gently led his readers through his discussions. Anyone who wished to "rise to a higher state" of knowledge concerning the transcendent and incorporeal God he worshipped first had to understand that God has no attributes.28 Neither qualities nor characteristics; no, not even existence, nor even unity, are part of the divine essence. Anyone who wished to be serious about his religion, it would appear from the Guide, had to strive for the rigor of thought which Maimonides possessed to an awesome degree.

In ordinary speech, he said, an attribute of an object is "superadded to its essence, and is consequently an accident"; that is, the attribute is a quality, or property, such as the white color of a white piece of cloth. Thus, when we say that "man is a speaking animal," we mean that the subject, man, has the attributes of life and speech.29 Maimonides insisted that this manner of describing God is completely inappropriate, inasmuch as God is immaterial, has no relationhsip to space and time, and is completely other than human experience.

Maimonides observed that when "our Teacher Moses" prayed: "Show me thy way, that I may know thee, that I may find grace in thy sight" (Exod. 33:13), he was asking that God should let him know God's attributes and God's essence. God answered both petitions. The utterance, "show me thy glory" (Exod. 33:18), meant that Moses prayed in particular for a knowledge of God's attributes. God replied: "'I will make all my goodness to pass before thee'" (verse 19).30 From time to time, Maimonides expressed ideas that were picked up and developed in later centuries. His recondite ruminations on the attributes and essence of God were the occasion of two prescient insights into the way the natural world is organized.

First, "all my goodness" meant that God would show Moses the entire creation, of which it was written: "And God saw everything that he had made, and, behold, it was very good" (Gen. 1:31). And second, this definition of "goodness" implied that God would give Moses the ability to understand how the parts of the natural world work together; that is, Moses would have the ability to "comprehend the nature of all things, their relation to each other, and the way they are governed by God both in reference to the universe as a whole and to each creature in particular."31 In other words, Moses could know his actionsˇas distinguished from his attributesˇbut not his essence.32 There was, the Rambam was convinced, "no possibility of obtaining a knowledge of the true essence of God."33

Maimonides, who had seen his share of calamities, persecutions, and sufferings, filled his pages with biblical instances where God guided those who had no claim on his guidance, and where his actions were therefore typically called, "merciful and gracious, long-suffering and abundant in goodness" (Exod. 34:6).34 The formula that he devised was that "all attributes ascribed to God are attributes of His acts, and do not imply that God has any qualities."35 For that reason, he declared that we should say "the Lord liveth" (Ruth 3:13), rather than "the life of the Lord."36

The Origin of Science

His discussion is pertinent to understanding the rise of modern science because, in one of his breaks with the Aristotelian view of the cosmos, he recognized a clear distinction between the Creator and the creation. This he did in explaining what he meant by the absolute otherness of God.

There cannot be any belief in the unity of God except by admitting that He is one simple substance, without any composition, or plurality of elements; one from whatever side you view it, and by whatever test you examine it; not divisible into two parts in any way and by any cause, nor capable of any form of plurality either objectively or subjectively.37

Nor was this all. Maimonides saw that this complete distinction between the Creator and the creation meant that the creation existed in a state of contingent dependence on the Creator. He wrote:

All we understand is the fact that He exists, that He is a Being to whom none of His creatures is similar, who has nothing in common with them, who does not include plurality, who is never too feeble to produce other beings, and whose relation to the universe is that of a steersman to a boat; and even this is not a real relation, a real simile, but serves only to convey to us the idea that God rules the universe; that is, that He gives it duration, and preserves its necessary arrangement.38

Creation Versus Eternality

That the Guide could have been written and rapidly distributed in the latter part of the twelfth century speaks much for the freedom of expression found in Saladin's Egypt. Maimonides was a Jewish believer, writing primarily for a Jewish audience, and he agreed with Christians and Muslims on the fundamental tenets of monotheismˇthe existence, oneness, transcendence, and the incorporeality of God. But he was questioning the particular arguments for creation put forward by the orthodox Muslim theologians, known as the Mutakallimunˇarguments by which they sought to uphold their own Islamic faith.

Critique of the Theologians

The Guide (I, chaps. 73˝76) reveals that one school of Muslim theology, the Kalam, had a unique and rather strange picture of nature.39 The Mutakallimun (the theologians) began with creation, and went on from there to their belief in the existence, unity, and incorporeality of God. To establish the logic of creation was, therefore, a principal objective. But to do that, they interpreted nature according to their own theological preconceptions of revelation. In so doing they did not hesitate to give out radical views concerning geometry, time, and the structure of matter and space.

The creation of the world did not occur just at the beginning, these theologians announced, but was occurring all the time. Nature was subdivided and fragmented into individual instants and bits of time and matter, each bit of which God was repeatedly creating. The Mutakallimun were willing to rewrite the science and mathematics of the day. No particle of time or matter survived more than an instant, but was immediately recreated by God in a continuous process. God kept on creating atoms, time, "accidents" (qualities or properties), and therefore even knowledge in the mind. Maimonides simply could not believe that nature was organized in such a way.40

The Mutakallimun were willing  to rewrite the science and mathematics of the day. 
No particle of time or matter survived more than an instant, but was immediately 
recreated by God in a continuous process...Maimonides simply
 could not believe that nature was organized in such a way.

He had a question for the Aristotelian theologians: How could either creation with a beginning, or continuous and repeated creation with no beginning, be advanced as a basis for faith?41 He asked the Mutakallimun this question because philosophers themselves had disagreed for the previous thousand years on whether the universe was eternal or had a beginning. In either case, the existence of God would be an open question. His chapters on the Kalam (I, 73˝76) are the most outspoken in the book, and were directed to Muslim theologians who were his contemporaries.

Qualities and Accidents

Causation came under particular scrutiny. Qualities were not properties of the whole, according to the Kalam, but each atom had its own accidents of color, smell, motion, and even life; absence of an accident was itself an accident. When a piece of cloth was treated with indigo, he said, by way of opposing this view, the "accident" of black color did not last, but God kept on creating the blackness of each atom. Knowledge we have today, we did not have yesterday.

If the Muslim theologians were correct, he continued, God repeatedly created the properties of an object "without the intervention of a natural force or of any other agency." In fact, most of the theologians held that "it must never be said that one thing is the cause of another."42 Since death was also an "accident," this meant that death was constantly being replaced by death.43 The repeated creation of every particle and accident meant a denial of Aristotelian causation, which he could never abide.

A couple of times the theologians were reasonably correct. For one thing, they posited the existence of a vacuum; otherwise, they said, how could atoms move?44 In view of the venerable Aristotelian horror vacui, an idea that would be cherished for centuries to come, it is curious to find the idea of the vacuum in the twelfth century; Maimonides objected. They also said that the individual atoms of different objects were all the same; the atoms of iron were like those of cream, the differences residing in their "accidents."45 This belief, that the basic particles of nature were fundamentally alike, would last well into the nineteenth century.46

As often as not the atomism of the Mutakallimun led to absurdities. Anything conceived by the imagination was possible: an elephant as small as an insect, a man as tall as a mountain; this was so because of the equality of atoms and accidents. "They do not ask whether the reality confirms their assumption," sighed Maimonides.47 According to their atomism, they believed that time could be divided indefinitely. But, he wanted to know, how could time consist of instants that had no duration? or objects and space consist of particles that had no magnitude or extension?

The probing criticism of Maimonides notwithstanding, the Muslim theologians with their bizarre talk of instants of time, space, and matter may have been on to something, at least in one area of knowledge. In the seventeenth century the concept of divisibility would be taken up anew and developed into the calculus.48

If we apply the time-honoured metaphor of the so-called two books, God's Word and God's Works, to this twelfth century debate, it might be useful to say that Maimonides's method was opposite from that of the Mutakallimun. He was interpreting revelation according to his own Aristotelian conception of nature. On the other hand, the theologians were interpreting nature according to their own views of the Qur'an. "Their sole object is to fashion the Universe according to their peculiar opinions and beliefs," which were derived from the Kalamˇtheir brand of theology.49

However laudable their efforts in the defence of creation, those theologians had abandoned the regularity of nature and the possibility of scientific prediction, and in so doing had left no basis for theism:

They denied the nature of the existing things, misrepresented the properties of heaven and earth, and thought that they were able, by their propositions, to prove the creation of the world, but in fact they were far from proving the creatio ex nihilo, and have weakened the arguments for the existence, unity, and the incorporeality of God. The proofs of all these doctrines must be based on the well-known nature of existing things, as perceived by the senses and the intellect.50

Critique of the Philosophers

"We do not reject the Eternity of the Universe, because certain passages in Scripture confirm the Creation; for such passages are not more numerous than those in which God is represented as a corporeal being." Ibn Aknin was still puzzled. He had just learned that Muslim theology did not have sound arguments for creation; and that sense experience was a basis for theism. His mentor was now writing to tell him that in fact it was as easy to harmonize certain passages of Scripture with Aristotelian eternality.51 Moreover, in letter after letter from Cairo, he was being informed that an absolute "proof does not exist in Nature" for creation. For Maimonides, the job therefore still remained to establish a sound basis for creation; otherwise someone would come along and shake ibn Aknin's faith, whereupon he would take up Aristotelian eternality, which, Maimonides warned him by mail, "is contrary to the fundamental principles of our religion."52 What was poor ibn Aknin to do?

Whereas the Muslim theologians were arguing from the creation to their belief in theism, the Muslim philosophers, who of course were Aristotelian, looked at the night sky and declared that the heavens were eternal. At any rate, the world certainly was either eternal or had a beginning. That much was plain. It was also plain that in either case the existence, unity, and incorporeality of God could be assumed. That meant that faith in the eternality of the world was as religious as faith in the creation, possibly more so, since for the Greek mind nature was deified. At least with respect to the existence of God, it would seem that the philosophers and theologians were in agreement. But that is essentially why ibn Aknin was perplexed.

The Bible and Aristotle's Spheres

When Maimonides the puzzle-solver gazed at the night sky, he saw every reason to suppose that "the well-known nature of existing things" had been amply explained.53 Indeed, for fifteen hundred years Aristotelian cosmology had held sway. On only one point did Maimonides disagree with the twenty-six proofs put forward by the philosophers for the existence of God: the eternity of the universe.54 In the next stage of this twelfth-century debate, he examined what they had to say about the eternity of the world.

While disagreeing with the contention of the Muslim philosophers that the world was eternal, Maimonides agreed with them that the prevailing cosmology was perfectly consonant with Scripture, whether the Bible or the Qur'an. According to Aristotle's thought, all the celestial bodies, that is, the sun, moon, planets, and stars, rode on the crystalline, transparent, and corporeal spheres which revolved eternally in perfect, Aristotelian circles around the Earth.55 The outer sphere, which was composed of the quintessence and had no stars, was kept in motion by God, who was the "Prime Motor," he explained, and from this sphere emanated the influences to control all events on Earth, such as the Aristotelian cycles of "genesis and destruction."56 Maimonides was obviously well read in the astronomy of his day.

While disagreeing with the contention of the Muslim philosophers that 
the world was eternal, Maimonides agreed with them that the 
prevailing cosmology was perfectly consonant with Scripture...

The Bible gave abundant evidence that those spheres were animate, intellectual, and capable of comprehension. For example, when the Psalmist wrote, "The heavens declare the glory of God" (Ps. 19:2), the verb he used always applied to intellectual beings.57 This and other passages were said to be fully in accord with the opinion of Aristotle. When Aristotle had further investigated the subject, he found that the spheres had different velocities and directions, and their action was transmitted by spiritual and incorporeal "Intelligences," which moreover did not reside in the spheres and whose number probably agreed with the number of the spheres. Maimonides thought the number of these Intelligences might be ten. Of these, nine corresponded to the spheresˇthe outer, the spheres of the stars, and the seven planetsˇand the innermost "Active Intellect," which controlled the transitions on Earth from potentiality to actuality and transmitted Aristotelian form to matter.58 He was apparently adopting the ninth sphere, just outside the fixed stars, that had been added by Arab astronomers.59

In the biblical passage, "And to rule over the day and over the night" (Gen. 1:18), the verb referred "to the power which the spheres possess of governing the earth." Since the biblical term "angel" was a synonym for "Intelligences," or "intellectual beings," Aristotle's Intelligences were therefore angels, and the said power of the spheres was undoubtedly transmitted actually by angels, although the cosmos probably had more than ten of them. Because these spheres acted collectively as one, it was clear that "we can prove the Unity of God from the fact that this Universe is one whole."60 It was a rational and biblical view of nature that Maimonides was presenting, one that was sublime and coherent: the crystalline spheres revolving around the Earth, and God superintending the sublunar regions through the mediation of ministering angels. "It may be that by Nature the Divine Will is meant."61

Faith, Reason, and Sense Experience

But the more that Maimonides gazed at the night sky the more he was convinced that the philosophers' arguments, however venerable and weighty, were not conclusive. Even Aristotle himself was "well aware that he had not proved the Eternity of the Universe." In his book, The Heavens and the World, Aristotle had represented his theory as an "opinion" and his proofs as "arguments."62 Was Aristotle ignorant of the difference between opinion and demonstration? between argument and proof? Certainly not; he was only intending to show his preference. In fact, continued Maimonides, Aristotle said: "'There are things concerning which we are unable to reason, or which we find too high for us; to say why these things have a certain property is as difficult as to decide whether the Universe is eternal or not.'"63 Maimonides could do worse than to agree with Aristotle.

Moreover, the present state of an object, "perceived with our senses," gives no clue whatsoever as to its past condition. "Take, e.g., the human ovum as contained in the female's blood."64 Just by looking at the adult body we cannot tell how it grew as a fetus:

We therefore do not reject as impossible the opinion of those who say that the heavens were produced before the earth, or that certain species of animals have been in existence, and others not. For the state of the whole Universe when it came into existence may be compared with that of animals when their existence began.65

Strange words, these are, appearing as they did in the twelfth century. It was monotheism, was it not, that was prompting Maimonides to say that irreversible changes could occur in the universe? Where else did he get this idea? From Aristotle? In sum, he was affirming that the philosophers' arguments for eternality were as faulty as those of the theologians for creation. Yet he still wanted to show the possibility and even probability of creatio ex nihilo in which he firmly believed. And whatever was he to do about ibn Aknin's perplexity? He turned again to the night sky.

Critique of the Astronomers

Although Maimonides took obvious delight in contemplating the revolutions of the celestial spheres, he was not so much of an Aristotelian that he was unable to subject Aristotelian cosmology to critical scrutiny. Nor, as an orthodox Jew, was he unable to see the fundamental difference between Aristotle's Prime Mover and the God of Abraham, Isaac, and Jacob. There, in his monotheism, of course, was the crux of the debate. He took another look at the night sky and came up with insights and questions that would be of consequence in the history of science.

Why did one sphere move from east to west and another from west to east? Why did they move with different velocities? His monotheism had conditioned the operation of his mind so that he was able to look at nature in a new way. He was able to raise questions that could not be answered by Aristotelian thought. It would not have occurred to the strict Aristotelians of the day even to ask such questions as these, or at least not in the bold manner in which he posed them; for the differences in direction and velocity were said to be a necessary part of the heavens, and these variations were to be explained by the Aristotelian "forms" that had been imparted to the spheres.66

Maimonides saw a difficulty with Aristotle's two kinds of motion, which were rectilinear and circular. In the case of rectilinear motion, which occurred only in the sublunar regions, the motion was basically of two kindsˇupward and downward. The inference could therefore be made safely that these two directions were caused by two different "forms" that were imparted to the elements. But the motion of the spheres was all of one kindˇcircularˇand hence their "forms" should be the same.67 The spheres ought really to move in one direction and at the same speed. Why, then, had the spheres, while displaying circular motion only, received these obviously different forms? Even Aristotle had not been able to give a satisfactory answer. To Maimonides, the explanation was easily given by the creation: God had chosen the direction and velocity of each sphere, and these variations were therefore not a "necessary" part of the heavens.68

Causation and Design

According to Aristotle, explained Maimonides to ibn Aknin, "the Universe is inseparable from God; He is the cause, and the universe the effect; and this effect is a necessary one." Therefore in the Aristotelian conception, the question about why the universe exists in one way and not in another did not even arise. "The nature of everything remains constant, that nothing changes its nature in any way, and that such a change is impossible in any existing thing." But according to theism, "all things in the Universe are the result of design, and not merely of necessity; He who designed them may change them when He changes His design."69

An even more striking mark of this "voluntary determination" could be found in the concentration and distribution of the stars themselves. Some were large, others small; here we notice two stars, over there ten close together; elsewhere we find a place empty of stars. Why should the stars be distributed as they are? How could this be explained by Aristotle's "laws of Nature" by which everything emanated from the Prime Mover by necessity?70

Of course, Aristotle did believe in design. The Prime Mover, as the most perfect Intellect and First Cause, was eternally pleased and delighted with everything that derived its external existence from itself. But this had nothing to do with design in the biblical sense, said Maimonides, for design and choice applied only to things not yet in existence. According to Aristotle, he continued, God's relationship to the universe was such that he could not change anything even if he tried.71 Indeed, if he could make a change, it would only diminish his perfection.

The thought did cross Maimonides's mind that with all the doubts he was raising, he might be setting in motion the overthrow of the entire Aristotelian system. He quickly dismissed that eventuality for it was clear to him, he wrote, that everything Aristotle had said about the region between the sphere of the moon and the center of the Earth was entirely correct. The more he thought about these matters, however, the more he was convinced that whatever Aristotle said about the regions above the moon were for the most part "mere imagination and opinion," and this included even parts of the Metaphysics. Still, he admitted, Aristotle might be excused for not fully explaining those stellar variations.72

Epicycles and Eccentrics

Ibn Aknin, meanwhile, had been studying the Almagest, in which Ptolemy had described a system of epicycles and eccentrics in order to explain the observed variations in direction, luminosity, and velocity of the planets. Maimonides devoted an entire chapter (Part II, 24) to this celestial machineryˇa quite wonderful chapter it isˇand as he warmed to this subject he waxed unhappy and showed some perplexity of his own. Those two explanatory devices, it appeared, were also unsatisfactory.

Take epicycles. Basic to physics was the principle that the universe had only three kinds of motionˇ"from the center, towards the center, and round the center"ˇand the reason why the Earth remained stationary was to provide a center round which the heavens could move.73 But an epicycle moved neither away from, toward, nor round this center; it moved round an imaginary point which itself revolved.

The eccentrics did not help either, because an eccentric sphere moved round an imaginary point that was at some distance from the center of the universe, that is, from the center of the Earth. Thus the center of the sun's sphere was not the center of the Earth, but it was located undoubtedly between the moon and the sphere of Mercury.74

"Now, consider how improbable all this appears according to the laws of Natural Science," by which Maimonides meant Aristotelian cosmology. Why should the paths of Venus and Mercury be inclined at an angle? "It is impossible to imagine material beings under such conditions."75 On the other hand, astronomy had no alternative to the Aristotelian-Ptolemaic explanation. How could the variations in direction and velocity of the planets be described without recourse to epicycles and eccentrics, which produced results that in the case of the Moon were "perfectly correct, within one minute"?76

Maimonides' reasoning makes Chapter 24, Part II of the Guide an instructive lesson in what constitutes a useful scientific theory. Arab astronomers probably did not really think that a planet revolved on a circle which itself revolved on a larger circle (rather like a Ferris wheel), whose center was some distance from the center of the Earth. For them, as for present-day astronomers, the question was: what theory best explained the phenomena?

Quite likely during weeks of watching the night sky, Maimonides often wondered why certain luminous points, that is, the planets, in moving east through the constellations, would stop, move westward, and then east again. For example, Mercury requires 116 days for retrogression; Venus 584 days.77 The intricate mathematics of epicycles did explain the retrograde motions of the planetsˇthe wandering stars, as they were calledˇand to increase the match between observation and theory various Arab astronomers heaped epicycles on epicycles.

By invoking the will of God, [Maimonides] was able to identify weaknesses 
in the physical principles of Aristotelian cosmology. In so doing, 
he inadvertently set the agenda of astronomy for the next half millennium.

The Arab astronomers had settled on a theory that would explain what they saw; a "true" theory was not required. Maimonides agreed: "The theory of Aristotle, in explaining the phenomena in the sublunar world, is in accordance with logical inference." He was perfectly aware that astronomy did not "profess to tell us the existing properties of the spheres" but was rather a theory that was "in agreement with our observations." He was struggling with a second feature of an acceptable scientific theory; in addition to saving the phenomena, the theory must do so with the least possible complications. Astronomy was not quite ready for that. We really know nothing about the heavens, he admitted, "except for a few mathematical calculations, and you see how far these go."78

By critically examining the prevailing views of astronomy, Maimonides was able to argue to the admissibility and probability of creation. Because of the numerous inconsistencies he found in the cosmology of his day, he believed it was utterly impossible to reconcile Aristotelian eternality and monotheistic creationˇ"that of necessary existence by causality, and that of Creation by the desire and will of a Creator." In his view, it was absurd to say that the relationship of the universe to God was a permanent and necessary connection of effect with efficient cause, and to turn around and say at the same time that the universe resulted from the will of God.79 The better explanation for the observed variations in the heavens was therefore creatio ex nihilo by the will of God.

For Maimonides in the twelfth century, it was only when he applied the theological concept of the will of God that he was able to question the prevailing views of astronomy. In Chapters 19˝24, Part II of the Guide, he raised thirty-three separate questions concerning planetary and stellar phenomena.80 By invoking the will of God, he was able to identify weaknesses in the physical principles of Aristotelian cosmology. In so doing, he inadvertently set the agenda of astronomy for the next half millennium.


The Dalalat al-HairinˇMaimonides wrote the Guide for the Perplexed in Arabicˇrecalls the writings of Augustine in the fourth century. A statement of a mighty and sublime faith, the Dalalat also presents a vision of a City of God in which the divine will that called forth the world is expressed with justice and mercy in the affairs of humankind. As for creation and eternality, the reader can usefully begin with Books 11, 12, and 13 of the Confessions and Books 11 and 12 of the City of God, which were written without the benefit of Aristotle's works; and go on from there to Chapters 68˝76, Part I and the Introduction and Chapters 1˝26, Part II of the Guide for the Perplexed, which were written with the benefit of Aristotle's works. Or one can begin with Maimonides and go back to Augustine, because their works complement each other.

Before the Dalalat was finished, meanwhile, the presence of the Jewish sage was brought to the notice of Saladin's vizier, al-Qadi al Fadil, who in about 1187 appointed him as a physician to the court in Cairo.81 With his name on Saladin's payroll and his days becoming busier than ever, he assumed the medical post he would hold for the rest of his life.82 Whenever Saladin was in town, Maimonides had to wait on him every day. The Jew from Cordova advised the Sultan of Egypt to get his rest, take exercise, eat right, and bathe regularly.83

Besides his official duties, Maimonides wrote at least ten treatises on medicine; he carried forward these projects even while he was working on the Dalalat al-Hairin.84 He also provided leadership to the Jewish community and on the sabbath participated in the synagogue. Apparently he married twice; his only son, Abraham, was born in 1187 and became a leader in the Jewish community in Egypt.85

As soon as the Dalalat was finished, in about 1190, the Arabic text was quickly copied and distributed far and wide. Before long learned Jews were teaching the work in mosques and learned Muslims were explaining what he meant to Jewish congregations.

In his arguments for creatio ex nihilo, 
in the numerous critical references to Aristotle, and in the emphasis on the will of God,
 the Guide may be construed as a pivotal commentary on Aristotle. 
By thus questioning the authority of Aristotle, 
the Guide played an unheralded and unforeseen role 
in making possible the rise of modern science.

The sage of Fustat was at the zenith of his fame and prestige. From Jerusalem came an invitation from Richard the Lion-hearted to serve as his physician, an honor he respectfully declined.86 His Dalalat aroused delight and perplexity; in due course, consternation and controversy; and inevitably, learned commentaries. In all cases, it aroused further respect for its author. In 1205 his friend Rabbi ibn Tibbon brought out a Hebrew translation, entitled Moreh Nebuchim.87 This edition was rapidly copied and distributed to far-flung Jewish communities. Many copies, made in succeeding centuries, are extant, some with brilliant, multi-color illuminations that turn up today in elaborate library exhibits and are reproduced in expensive greeting cards.

The first Latin translation, the Doctor Perplexorum, came out in 1232. Shortly thereafter, theologians in Paris were eagerly comparing Arabic, Hebrew, and Latin editions. Thus the Guide passed into western thought, most prominently into the work of Thomas Aquinas.88

The Friedlönder edition, the first in English, in 1881, lists forty commentaries that were written, mostly by Jewish scholars, before the introduction of printing. One awe-struck writer declared that "there is no searching to his understanding," but that all the same a new commentary written by himself would undoubtedly help the young. Another wrote a commentary for his edification so that in his old age he might refresh his memory. A nineteenth century rabbi, perplexed by the Guide, gave it as his opinion that Maimonides was not the author after all, since he could not have written such heresy.89 Today, scholars contentedly devote goodly portions of their lives to the sage of Fustat, and count the time well spent.90

When Maimonides denied Aristotelian eternality, he inelectably lodged a fundamental doubt at the heart of Aristotelian cosmology. The question that he was astute enough to perceive was this: if Aristotle were mistaken about eternality, might not his other assertions about nature be mistaken as well?91 In his arguments for creatio ex nihilo, in the numerous critical references to Aristotle, and in the emphasis on the will of God, the Guide may be construed as a pivotal commentary on Aristotle. By thus questioning the authority of Aristotle, the Guide played an unheralded and unforeseen role in making possible the rise of modern science.

Having finished his work and having become the friend of Christians, Jews, and Muslims of all the ages, Moses Maimonides died on December 13, 1204 at the age of sixty-nine. A day of mourning was announced in Alexandria and Cairo.

The Rambam had expressed the wish to be buried in Tiberias. It is said that as the funeral cortege was slowly wending its way across the desert, a pack of thieves suddenly descended on the mourners. When the bandits learned who was in the casket, they fell back in shame and remorse, and begged that they might be allowed to accompany the procession as a guard of honor.92


I am obliged to George T. Scanlon, Professor of Islamic Art and Architecture at the American University at Cairo, for his informative letter to me in November 1984. Under his leadership, the excavation of Fustat in recent years has revealed a good deal of what life was like in that medieval town.

I also very much appreciate the cordial assistance given me in locating Maimonides references by Dan Sharon, of the Asher Library, Spertus Institute of Jewish Studies, in Chicago.

And I also received prompt assistance in other Chicago libraries: the Harold Washington, the Newberry, and the Regenstein.



1No one knows what Maimonides looked like. Here an unknown artist has given him a wise mien, though one thinks the famous sage is rather melancholy and sad in this pose, as though he were thinking of all the writing he was not getting done. The autograph, though, likely is authentic. From "Moses ben Maimon," Jewish Encyclopedia, vol. 9 (1905): 73.

2Moses Maimonides, The Guide For The Perplexed (New York: Dover Publications, 1956 [1804, 1881, ca. 1190]), 192. Translation by Michael Friedlönder, in 1881. This is the second English edition, hereafter referred to as Guide. For an excellent introduction to the thought of Maimonides, I suggest Lenn E. Goodman, Rambam: Readings in the Philosophy of Moses Maimonides, with commentaries and translation (New York: Viking Press [Jewish Heritage Classics, Series], 1976); and Oliver Leaman, Moses Maimonides (New York: Routledge, 1990).

3Solo W. Baron, "Maimonides," in Simon Noveck, ed., Great Jewish Personalities in Ancient and Medieval Times (B'Nai B'rith Department of Adult Education, Clinton, MD: Colonial Press, 1965), 204˝31; Goodman, Rambam, 1˝15; Guide, xv˝xxv; Abraham J. Heschel, Maimonides (New York: Farrar, Straus, Giroux, 1982); "Moses ben Maimon," The Jewish Encyclopedia vol. 9 (New York: Funk and Wagnalls, 1905), 73˝86. Much seems to be known about the life of Maimonides, due in large measure to the work of the thirteenth century Arab historian and physician, Ibn Abi Usaibia (IAU), whom Hitti called "the most distinguished historian of medicine the Arab world produced" (Philip K. Hitti, History of the Arabs [New York: Macmillan and Co., 1956], 686). IAU wrote biographies of some 400 Arab and Greek medical figures. Nineteenth-century studies of Maimonides relied on IAU and those biographies are frequently cited by present-day writers, whom I cite here. Also, see August MŞller, đber Ibn Abi Oceibia und seine Geschichte der Arzte, Studies on Ibn Abi Usaibia (d. 1270) and his Uyun al-anba fitabaqat al-atibba, Pt 2 (Frankfurt an Main: Institute for the History of Arabic-Islamic Science at Johann Wolfgang Goethe University, 1996 [1885, 1883]); and Hitti, History of the Arabs, 525˝7.

4The Umayyads are named for Mu'awiyah who, in A.D 661˝750, founded in Damascus the line of 13 caliphs that formed the first dynasty in Islam. Stanley Lane-Poole, The Story of the Moors in Spain (Baltimore: Black Classic Press, 1990) and Hitti, History of the Arabs, passim.

5Hitti, History of the Arabs, chap. 37, "The Umayyad Caliphate of Cordova" and chap. 40, "Intellectual Contributions." Philip K. Hitti,"Abd-al-Rahman I: Maker of History on European Soil" in Makers of Arab History (New York: Harper, 1971), passim. On the mosque of Cordoba, see Keppel Creswell and Archibald Cameron, A Short Account of Early Muslim Architecture (Baltimore, MD: Penguin Books, 1958), 213˝28; John D. Hoag, Islamic Architecture (New York: Harry N. Abrams, 1978), 77˝83; Don A. Halperin, The Ancient Synagogues of the Iberian Peninsula (Gainesville, FL: University of Florida Press, 1969). On the Jewish section of Cordova, see Eliyahu Ashtor, The Jews of Moslem Spain, 2 vols. (Philadelphia: Jewish Publication Society, 1973), I (1973): 291˝300.

6The Almoravids are named for the Murabits who were a religious and military brotherhood (ribat: a fortified monastery; Rabatˇthe capital of Morocco); the dynasty flourished from A.D. 1090 to 1147. See also Hitti, History of the Arabs, passim.

7The two essays, "Treatise on Logical Terminology," and "Essay on the Calendar," are in Isadore Twersky, ed., A Maimonides Reader (New York: Behrman Press, 1972).

8Fez was founded under Idris II who allowed the settlement of many Jews and Christians. Haim Zeev Hirschberg, A History of Jews in North Africa, vol. I: From Antiquity to the Sixteenth Century (Leiden: E. J. Brill, 1974), 99. See also Didier Madras and Boris Maslow, Fes, Capitale Artistique de l'Islam (Casablanca, Morocco: P. Bory, 1948).

9Sami K. Hamarneh and Glenn Sonnadecker, A Pharmaceutical View of Abulcasis al-Zahrawi in Moorish Spain (Leiden: E. J. Brill, 1963), 110, 127 and Geoffrey L. Lewis and Martin S. Spink, Abulcasis (936?˝1013?) on Surgery and Instruments; Arabic text and English translation of the Kitab al-Tasrif, also known as Kitab al-Zahrawi (Berkeley, CA: University of California Press, 1973).

10On the relationships between Jews and Muslims during the Middle Ages, I suggest: Merlin Swartz, "The Position of Jews in Arab Lands Following the Rise of Islam," The Muslim World, 60 (1970): 6˝24; Solomon Dob Goitein, Jews and Arabs: Their Contacts Through the Ages (New York: Schocken Books, 1964), especially chaps. 3˝7; Abba Eban, Heritage: Civilization and the Jews (New York: Praeger, 1983) and Bernard Lewis, The Jews of Islam (Princeton: Princeton University Press, 1984).

11On the massacre during the First Crusade, see Hitti, History of the Arabs, 638.

12Some 1,500 Jews lived in Cairo during the Middle Ages; see Eliyahu Ashtor, "The Number of Jews in Medieval Egypt," Journal of Jewish Studies, vol. 18 (1967): 9˝42; vol. 19 (1968): 1˝22. See George T. Scanlon, et al., "Preliminary Report: Excavations at Fustat," Journal of the American Research Center in Egypt (1964).

13On Fatimid life and times (named for Muhammad's daughter, Fatima), see Hitti, History of the Arabs, chap. 44, "Life in Fatimid Egypt." On Fatimid architecture, see Creswell, A Short Account of Early Muslim Architecture, 30, 215; Hitti, History of the Arabs, 630; and Hoag, Islamic Architecture, 136˝51.

14Fred Rosner and SŞsseman Muntner, The Medical Aphorisms of Maimonides (New York: Yeshiva University Press, 1970˝1971); Arthur David, trans., Commentary to the Mishnah Aboth (New York: Bloch Publishing House, 1968).

15Stanley Lane-Poole, Cairo: Sketches of its History, Monuments, and Social Life, with Illustrations (London: J.S. Virtue & Co., 1906), 95 and passim. Also Heschel, Maimonides, 66˝79. "Mishnah" means instruction, as developed chiefly before A.D 200.

16The "Epistle to Yemen" is in Twersky, A Maimonides Reader, 443˝62.

17On the Citadel, see Hoag, Islamic Architecture, 152˝3.

18Code of Maimonides, or Mishneh Torah, in 14 Books, in English translation, Books I and II: The Commandments, (Soncino Press, 1967); Books III˝XIV, (New Haven, CT: Yale University Press, 1956˝1963 [variously]). For an informative analysis of the Mishneh Torah see, Isadore Twersky, ed., Introduction to the Code of Maimonides (Mishneh Torah), vol. 23 (New Haven: Yale University Press [Yale Judaica Series], 1980).

19Guide, 9. Leo Strauss, "The Literary Character of the Guide for the Perplexed," in Joseph A. Buijs, ed., Maimonides, A Collection of Critical Essays (Notre Dame: University of Notre Dame Press, 1988), 30˝58; and Joseph A. Buijs, "The Philosophical Character of Maimonides' GuideˇA Critique of Strauss' Interpretation," in Joseph A. Buijs, ed., Maimonides, 59˝70.

20 Guide, 1.

21On Omar Khayyam, see Carl B. Boyer, "The Arabic Hegemony," chap. 13 in A History of Mathematics (Princeton University Press, 1985); Louis Charles Karpinki, Robert of Chester's Latin Translation of the Algebra of al-Khowarizmi (New York: Macmillan, 1915); Daoud Kasir, Ed., The Algebra of Omar Khayyam (New York: Columbia Teachers College, 1932).

22From the letter of Maimonides to ibn Aknin, Guide, Introduction, 1.

23Some devout Christians and Muslims, who were influenced by neo-Platonism as put forward by Plotinus, thought of creation as a kind of allegory, as a continuous emanation of the world by the will of God from his own inexhaustible essence. See Harry Austryn Wolfson, "The Meaning of Ex nihilo in the Church Fathers, Arabic and Hebrew Philosophy, and St. Thomas," in Studies in the History of Philosophy and Religion, vol. I (Cambridge: Harvard University Press, 1973), 209 . On Muslim chronology, creatio ex nihilo not present in the Qur'an, and views of Averro╬s, see Harry Austryn Wolfson, "The Meaning of Ex nihilo in the Church Fathers, Arabic and Hebrew Philosophy, and St. Thomas," 207˝21; "The Platonic, Aristotelian and Stoic Theories of Creation in Hallevi and Maimonides," 234˝49; and "The Twice-Revealed Averroes," 371˝401 in Studies in the History of Philosophy and Religion vol. I (Cambridge: Harvard University Press, 1973).

24Harry Austryn Wolfson, "The Kalam According to Maimonides," chap. 3 in The Philosophy of the Kalam (Cambridge: Harvard University Press, 1976).

25Guide, 13˝14. Wolfson, observing that neither the Bible nor the Qur'an describe God as "incorporeal," traced this designation to the first century Jewish philosopher, Philo Judaeus, in a very full discussion of this question, in Philo: Foundations of Religious Philosophy in Judaism, Christianity, and Islam, vol. 2 (Cambridge: Harvard University Press [Series: Structure and Growth of Philosophic Systems from Philo to Spinoza], 1947), 94˝101, 149˝64. Wolfson is a sine qua non for studies of this sort.

26Ibid., e.g., 28, and Part I, chap. 35.

27Ibid., I, chaps. 1˝70, 1˝107.

28Guide, 67; from Part I, chap. 5.

29Ibid., 68. On a discussion of Aristotelian "accidents," see E. J. Dijksterhuis, The Mechanization of the World Picture (Princeton: Princeton University Press, 1986), 19˝20.

30Ibid., 75.

31Loc. cit.

32Loc. cit.

33Ibid., 83.

34Ibid., 75.

35Ibid., 78.

36Ibid., 100, in chap. 68 of Part I.

37Ibid., 69.

38Ibid., 83.

39Ibid., 120˝44.

40Ibid., 123˝6.

41Ibid., 111.

42Ibid., 124, 125. Maimon was finding that the Aristotelian explanation of "secondary qualities"ˇcolor, magnitude, extension, and the likeˇwould not do. See Robert Boyle, Origin of Forms and Qualities (Oxford: H. Hall, 1966); and discussions by Dijksterhuis, The Mechanization of the World Picture, 434˝41; Edwin A. Burtt, The Metaphysical Foundations of Modern Physical Science (Garden City, NY: Doubleday Anchor Books, 1954), 180ff.

43Ibid., 126˝7.

44Ibid., 120, "Proposition II"; 121.

45Ibid., 129.

46On the concept of the atom through the ages, see Herbert Butterfield, "The Postponed Revolution in Chemistry," chap. 11 in The Origins of Modern Science (New York: Free Press, 1960).

47Guide, 128.

48Ibid., 81, 87. For the calculus, see E.T. Bell, Men of Mathematics (New York: Simon and Schuster, 1965 [1937]), on Isaac Newton, passim. On the interesting "minima naturalia," see Dijksterhuis, The Mechanization of the World Picture, 277˝9.

49Ibid., 127.

50Ibid., 144.

51Ibid., Part II, chap. 25, 199; see also 111.

52Ibid., p. 195.

53Ibid., p. 144.

54Ibid., Part II, Introduction, the proofs: pp. 145˝9. On the medieval view of the universe, I suggest C.S. Lewis, The Discarded Image (Cambridge University Press, 1964).

55Ibid., pp. 163˝4.

56Guide, Part II, Chapters 10˝12; quotes: pp. 151, 159.

57Ibid., 159.

 58Ibid. On "Intelligences," see 100˝2, 155˝8.

59Thabit ibn Qurra, a ninth-century astronomer in Baghdad, invented the ninth sphere; see George Sarton, Introduction to the History of Science, vol. I: From Homer to Omar Khayyam (Baltimore: Carnegie Institution of Washington, 1927), 599.

60Guide, 159, 160, 162.

61Ibid., II, chaps. 4˝10; 154, 166.

62Ibid., 176. Maimonides was referring to Aristotle's De Coelo, 1.10, 279b˝280a35.

 63Guide, 177. He was referring to Aristotle's Topics, 104b15.


Guide, Part II, chap. 17, 178˝80.

65Guide, 180˝1.

66Ibid., Part II, chap. 19; especially 185˝6 on forms. From Aristotle's many references to the "forms," as part of his theory of causation, I suggest: Posterior Analytics, 79a7; from the Physics, 198a30˝35; Parts of Animals, 640a15˝30; and the famous passage from the Generation of Animals, 729 a11.

67Ibid., 186.

 68Ibid., 187. By "necessary," he meant the Aristotelian concept of something that could not be other than it was.

69Ibid., 184. Maimonides' affirmation of "design" does not, of course, make him a twelfth-century "scientific creationist," as that term is used today.

70Ibid., 188, quotes: 187, 186.

71Ibid., 194.

72Ibid., 187, 194, 198.

 73Ibid., 196. For Aristotle on rectilinar motion: Physics, 263a2˝5, passim; for circular motion: Heavens, 269a25˝270a13, passim.

74Loc. cit.

75Ibid., 196, 197.

76Ibid., 198. I do not know how Maimonides arrived at this margin of error of only "one minute," or if it is correct. I suspect it was by a mathematical calculation rather than by a visual observation. Would a reader have an idea?

77Laurence W. Frederick and Robert H. Baker, An Introduction to Astronomy (New York: D. Van Nostrand, 1974), 120, 131˝2.

78Guide, 198.

79Ibid., 190, 211.

80I counted the questions; 186˝200.

81Bernard Lewis, The Jews of Islam, 100, 208; giving credence to this report and citing Arabic sources. Further to this question, see also Richard W. Bulliet, Conversion to Islam in the Medieval Period (Cambridge: Harvard University Press, 1979) and Nehemia Levitzion, ed., Conversion to Islam (New York: Holmes and Meier, 1979).

82On the famous and revered Saladin, see Hitti, History of the Arabs, 645˝53; Philip K. Hitti, "Salah-al-Din: Hero of the Anti-Crusades" in Makers of Arab History. Not to be overlooked: Hamilton Alexander Rosskeen Gibb, chap. 5, "The Armies of Saladin" and chap. 6, "The Achievement of Saladin" in Studies in the Civilization of Islam, (Boston: Beacon Press, 1962), and ˇˇˇ, The Life of Saladin (Oxford: Clarendon Press, 1973); Stanley Lane-Poole, Saladin and the Fall of the Kingdom of Jerusalem (New York: G. P. Putnam's Sons, Ltd., 1926.

83Heschel, Maimonides, 221.

84Meyerhof, "The Medical Work of Maimonides," in Salo Wittmayer Baron, ed., Essays on Maimonides, an Octocentennial Volume; 800th Anniversary of the Birth of Maimonides (New York: Columbia University Press, 1941), 265˝97. Fred Rosner, "Maimonides the Physician: a Bibliography," Bulletin of the History of Medicine, 43 (1969): 221˝235; Fred Rosner and SŞesseman Muntner, trans., Treatise on Hemorrhoids (Philadelphia: Lippincott, 1969); A still useful survey is: Harry Friedenwold, The Jews in Medicine, 2 vols., Introduction by Henry E. Sigerest; Vol. 1, chap. 12, "Moses Maimonides the Physician" (Baltimore, MD: Johns Hopkins University Press, 1944); Levy, in Charles Singer, ed. Studies in the History and Method of Science (New York: Arno Press [History, Philosophy, and Sociology of Science Series], 1917).

85On Abraham, Maimonides's son, see Heschel, Maimonides, 219.

 86"Moses ben Maimon," 80. Heschel, Maimonides, 218˝21. Bernard Lewis, "Maimonides, Lionheart, and Saladin," Eretz-Israel, I (1964): 70˝75.

87Guide, xxxii-xxxvii; Goodman, Rambam, 34, 35, 40. "Letter to Samuel ibn Tibbon" (in 1199), in Leon D. Stitskin, trans. and ed., Letters of Maimonides (New York: Yeshiva University Press, 1977). 130˝6.

88A mine of thoughtful information: Jacob Haberman, Maimonides and Aquinas: A Contemporary Appraisal (New York: KTAV Publishing House, 1979); Also, Isaac Franck, "Maimonides and Aquinas on Man's Knowledge of God: A Twentieth Century Perspective," in Buijs, ed., Maimonides, 284˝305; Etienne Gilson, "Homage to Maimonides," in Baron, ed., Essays on Maimonides, 19˝35. Also, see Jacob I. Dienstag, Studies in Maimonides and St. Thomas Aquinas (New York: KTAB Publishing House [Bibliotheca Maimonidica], 1975). Aquinas.

89Guide, xxxiii, xxxv, xxxii.

90Leaman, Moses Maimonides.

91Ibid., 194: "It may perhaps be asked why I have enumerated all the doubts which can be raised against the theory of Aristotle." But then he hurried on to explain why "This is certainly not the case."

92Heschel, Maimonides, 246˝7.

Additional References

 Bar-Sela, Ariel, Hebbel E. Hoff, and Elias Paris. "Moses Maimonides' Two Treatisses on the Regimen of Health." Transactions of the American Philosophical Society. Vol. 54 (4): 1˝50.

 Burrell, David B. Knowing the Unknowable God, Ibn-Sina, Maimonides, Aquinas. University of Notre Dame Press, 1986.

 Burrell, David B. and Bernard McGinn, Eds. God and Creation, An Ecumenical Symposium (on Christianity, Judaism, and Islam). University of Notre Dame Press, 1990.

 De Sacy, Antoine Isaac Silvestre. Relation de l'Őgypte, par Abd-Allatif, M╚decin Arabe de Bagdad. Paris: Treuttel et WŞrtz, 1890.

 Dreyer, John Louis Emil. A History of Astronomy from Thales to Kepler. New York: Dover Publications, 1953 (1905).

 Goitein, Solomon Dob. A Mediterranean Society: The Jewish Communities of the Arab World as Portrayed in the Documents of the Cairo Geniza. 5 vols. Berkeley: University of California Press, 1967˝1988.

 Le Porrier, Herbert. The Doctor from Cordova, a Biographical Novel about the Great Philosopher Maimonides. Garden City, NY: Doubleday, 1979.

 Maimonides, Moses (partial list):

 a. Treatise on Logic. New York: American Academy for Jewish Studies, 1938 (ca. A.D. 1151).

 b. Moreh Nevukhim, Hebrew translation (of Arabic version of the Guide) by Samuel ibn Tibbon. New York, Om Publishing, 1946 (ca. A.D. 1185).

 c.The Guide of the Perplexed, translation by Shlomo Pines. University of Chicago Press, 1969 (1963).

 d. Commentary on the Mishnah, translation by Fred Rosner. New York: Sepher-Hermon Press, 1975 (ca, 1180).

 e. "Letter to Samuel ibn Tibbon," in Stitskin, Leon D., translator. 1977 (ca. A.D. 1199).

 Mason, Stephen F. "Chemistry and the Atomic Theory of Matter." Chap. 36 in A History of the Sciences. New York: Collier Books, 1962.

 Multhauf, Robert P. The Origins of Chemistry, New York: Franklin Watts, Inc., 1967.

 Pines, Shlomo, translator. The Guide of the Perplexed, with introduction and notes. University of Chicago Press, 1969 (1963).

 Rosner, Fred (selected items):

 a. "Moses Maimonides' Contribution to Medicine" (Maimonides Award for 1969). Chicago: College of Jewish Studies, 1969.

 b. Moses Maimonides' Commentary on the Mishnah (translation). New York: Sepher-Hermon Press, 1981.

 c. Medicine in the Mishneh Torah of Maimonides. University of Denver, Maimonidin Society Center for Judaic Studies, New York: KTAV Publishing House, 1984.

 d. The Existence and Unity of God: Three Treatises Attributed to Maimonides (translation). Northvale, New Jersey: J. Aronson, 1990.

 Schneer, Cecil J."The Composition of Things." Chap. 9 in The Evolution of Science. Lanham, MD: University Press of America, 1960.