The Genius of Their Age
Ibn Sina, Biruni, and the Lost Enlightenment
Synopsis of this Post
This story takes place almost exactly one thousand years ago, in Central Asia.
For readers who don’t want to engage in my lengthy description of the life and times of two polymaths (Ibn Sina and Biruni), here is a summary of the major points:
The timeframe of events here is part of what is known as the Islamic Golden Age1, a period that ran from the eighth to the thirteenth centuries and was centered on Baghdad. Ibn Sina and Biruni lived and worked in an area of Persia mostly north and east of Tehran, where the present states of Afghanistan, Iran, Uzbekistan, and Turkmenistan all come together; reaching east into the Indus Valley (parts of modern Pakistan and India).
Biruni focused his research and writing on mathematics and anthropology. His work led to many breakthroughs (firsts) or major improvements in many areas. For example:
using the concept of specific gravity to determine the genuineness and quality of gemstones and precious metals
measuring the circumference of the earth to within a few miles of the modern number
calculating longitude and accurate distances between cities
comparing and harmonizing the calendars of different cultures
anticipating the work of later scientists such as Darwin and Einstein by observing the workings of evolution and relative motion
disagreeing with Aristotle on many things; e.g. holding that there would logically be habitable continents on the other side of the globe (which were, in fact, “discovered” by Europeans five hundred years later)
Biruni’s major lasting book was one on India, where he traveled extensively. He helped to promote the use of the Hindu numbering system (later erroneously called “Arabic numbers” in Europe since they had been conveyed from India by Arabs)
Although Ibn Sina was well versed in many of the same areas as Biruni, he concentrated his writing on medicine, the law, and metaphysics.
contrary to Biruni, he was an apologist for Aristotle.
Ibn Sina’s masterpiece was his Canon of Medicine, which became the standard textbook of medical practice in Europe and elsewhere for the next several hundred years
Ibn Sina and Biruni knew each other, corresponded, and even worked together in the same court for several years. Yet neither one referenced the work of the other, suggesting that they were rivals rather than friends.
In all of their writing, both men were hiding or minimizing their religious skepticism. They both disagreed with then-current religious dogma on the important concept of God’s immanence. On this, they agreed with Plato and Aristotle that God was a Creator who then stepped aside. This strikes me as being identical with the beliefs of indigenous American cultures that I am familiar with, and consonant with the views of Spinoza and the skepticism of David Hume.
This summary (and my entire post) can only touch on the rich variety of topics studied, improved, and written about by these two men. This lengthy post has exceeded the space limits of some email clients (such as gmail), so if you wish to read it in its entirety (as I hope you will), you may need to view it in your browser or click “view entire message” in order to read it in your email app. I’ve put many lengthy quotations and comments in footnotes in order to allow the main story to flow more quickly.
And so, my story begins…
God be with you till we meet again
That may seem like a strange way to start a post, since the contraction of “God be with ye” is our word “goodbye” — the signal of the end of a conversation or even of a relationship.
The Christian hymn with that title was written in 1882, and reflects God’s immanence. In contrast, the Platonic tradition (accepted and enhanced by Aristotle) held that God could not be of this world. Early Christian theologians blended the Greek and Hebrew traditions and agreed that evil was not created by God, but was instead the absence of goodness.
The Christian God, however, was very much the God of Abraham (and Noah and Job and Jonah); a personal God who was active in the human world. The Allah of Islam followed in this tradition. Other traditions, such as Buddhism and the indigenous beliefs in the north and east of North America hold to the idea of a divine Creator who is not involved in our world.
In the sixteenth century, the Scientific Revolution created a dichotomy between those who believed in divine intervention and those who held out that the Universe is ordered by the Laws of Nature. Spinoza (1632-1637) earned the derision of both his Jewish community and the Christian Church for his proposal that God and Nature are the same thing.
My conjecture is that David Hume was heavily influenced by Spinoza. As far as I know, he never admitted this, but he spent a lot of time in France during a period when Spinoza’s writings were very popular. In any case, Hume’s writing and personal persuasion exerted much influence on our Founders, who were for the most part Deists, not Christians. Benjamin Franklin, for example, spent at least a couple of weeks visiting Hume in his home in Edinburgh.
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.
That last phrase replaced the mention of Property in earlier philosophical writings because property was deemed to be alienable (subject to changing laws). There was no suggestion here (or elsewhere in the Founding documents) that God was active in human affairs.
The roots of the European Scientific Revolution may be deeper than is commonly appreciated. Two eleventh century Central Asian individuals who espoused views that reappeared during the European Renaissance are venerated in the book under consideration here.
Both men were born around the same time (Ibn Sina lived from 980 to 1037 and Biruni from 973 to 1048) in the same part of the world, and they knew each other. For a seven-year period beginning circa 1005, they both worked in the same royal court, serving the Shah (King) of Khwarazm. It is easier to trace at least part of Ibn Sina’s legacy, since, as mentioned in my synopsis, one of his works (Canon of Medicine) was used in Europe for hundreds of years as the standard manual of medical practice.
Biruni’s influence is more diffuse and speculative. When Isaac Newton famously wrote in 1675 that, "If I have seen further, it is by standing on the shoulders of giants,", one of those giants may very well have been Biruni, who wrote of infinitesimal calculus six centuries before Leibniz and Newton. The lack of attribution was common. Until relatively recently there was no concept of intellectual property and its protection by way of patents and copyrights.2
Ibn Sina was a fierce defender of Aristotle, yet he at times parted ways with the Ancient Master in his religious beliefs, tending more to the Islamic Allah of mercy and vengeance than to the Aristotelian god of creation (removed from the world of humans).3
Many Christian theologians, such as Albertus Magnus and his student Thomas Aquinas, referred to Ibn Sina as an authority and interpreter of Aristotle [page 206], despite this apparent split and inconsistency in Ibn Sina’s beliefs.
Biruni, for his part, was open to the idea that the earth revolved around the sun, and was therefore a precursor of thinkers like Galileo and Copernicus, both of whom earned the ire of the Christian Church for their apostasies relative to Aristotle’s science, which was not heliocentric. Biruni also anticipated Einstein’s theory of relativity by declaring that it didn’t matter whether the universe was centered on the earth or the sun, since all motion was relative.4
Biruni has been credited with many firsts, among them the “first anthropologist”5 although it is not clear how or even whether his work influenced the development of that field. Lewis Henry Morgan (1818-1881) is often cited as the founder of modern comparative anthropology. Morgan’s education including readings (probably in the original Greek and Latin) of many ancient scholars, but it is doubtful he read anything by Biruni, who wrote mostly in Arabic and also in Persian.
Motivation for the development of Spherical Trigonometry
Like many (perhaps most) schoolchildren in this country when I was young, I learned the verse
In fourteen hundred ninety-two, Columbus sailed the ocean blue.
The folklore that surrounded Columbus was full of misrepresentations. The poem that begins with that verse, for example, goes on to describe Columbus as “brave” — we were taught that most people believed the earth was flat, but Columbus had somehow secretly figured out it was round. In fact, the astrolabe, a device based on the spherical properties of the earth, had been in use for at least a thousand years before Columbus. (Not a “compass” as was mentioned in the poem.6)
Columbus navigated his way to the West Indies with the aid of an astrolabe7 that had been improved by Arab astronomers, as well as by Ibn Iraq, Biruni, and their successors. [page 27]
It is also interesting to note that Biruni speculated that there might be a habitable land mass on the other side of the globe. In this, he was in direct disagreement with Aristotle, who had declared that the two-thirds of the globe west of Europe and east of Asia was all water — the World Ocean. [pages 139-140]
… five centuries before Columbus, a mathematician-astronomer who had never seen an ocean, [Biruni] correctly hypothesized the existence of what became known as North and South America as inhabited continents. [page 141]8
Columbus may have been a good navigator, but he was obviously a poor (or misinformed) mathematician, else he would have known how much farther he would have had to have gone to reach India.
Helen Pfeifer begins her essay (Flying Man) in the London Review of Books with this revelation:
In the early 11th century, at Nandana, a fort in the mountains of northern Punjab, the polymath Abu Rayhan al-Biruni realised his dream of measuring the size of the earth. Two centuries earlier, the Abbasid caliph al-Ma’mun had sent a group of astronomers into the desert for the same purpose. The advantage of Biruni’s method was that it ‘did not require walking in deserts’. He simply calculated the height of one of the mountains and the angle it formed with the horizon on the plain below. He could then construct a triangle, one of whose sides was the height of the mountain plus the earth’s radius. Trigonometry would do the rest. The circumference Biruni calculated (after some later revisions) came within just eighty miles9 of modern measurements. Only in the 17th century would Europeans improve on his figures.
It had been known since ancient times that the earth is a sphere. The first known attempt to estimate its size was made by Eratosthenes circa 240 BCE.10 Earlier, around 255 BC, Eratosthenes had invented the armillary sphere. The astrolabe was essentially a device to reduce the sphere to a flat surface for ease of use and transport, and had come into common use by the fifth century of the current era.
Both as part of his official duties and on his own, Biruni traveled to India and interviewed numerous Indian mathematicians. From these encounters, he learned their latest thinking on spherical trigonometry. This involved, among other things, taking into account the curvature of a sphere (or any circle) by contrasting the length of an arc with the length of a chord. This is perhaps what motivated Biruni to undertake his own measurement of the earth’s circumference, since some earlier attempts had probably used plane geometry in their estimates (although Eratosthenes had his own method of estimating the length of an arc).
Biruni’s knowledge of spherical trigonometry led him to propose improvements to astrolabes. One “would enable the observer to measure angles by using not only the sun but also the moon and certain stars.” [page 51] “Over the years, he was able to introduce an array of further improvements on this essential scientific and navigational tool.” [page 52] Along the way, he proposed a method for mapping a hemisphere, which was evidently lost to the world until “the Italian cartographer G. B. Nicolosi reinvented it in 1660…” [ibid]
Other Contributions by Biruni
In addition, Biruni was involved in using and promoting Indian numerals (later erroneously called Arabic numbers in Europe because they had come there by way of scholars writing in Arabic). Leonardo of Pisa (Fibonacci) popularized their use in the thirteenth century.
The book Finding Zero gives a fascinating account of the author’s search for the earliest recorded use of the concept of zero. The numbers zero to nine are descended from the Brahmi numeral system, which was used in India as early as the fourth century BCE.
Al-Khwārizmī's contributions to mathematics, geography, astronomy, and cartography established the basis for innovation in algebra and trigonometry. His systematic approach to solving linear and quadratic equations led to algebra, a word derived from the title of his book on the subject, Al-Jabr.
On the Calculation with Hindu Numerals, written circa 820-825, was principally responsible for spreading the Hindu–Arabic numeral system throughout the Middle East and Europe. It was translated into Latin as Algoritmi de numero Indorum. Al-Khwārizmī, rendered in Latin as Algoritmi, led to the term "algorithm."
Biruni was an avid follower of Al-Khwārizmī's, and wrote a (now lost) book in his defense called Disproving the Lie. [page 60]
One of Biruni’s major surviving works (with a long title that included The Determination of the Coordinates of … Cities) has to do with the measurement of longitude. Also, according to Starr
Biruni reveals himself as an evolutionist. He believed that after God created the world, it underwent profound changes… In subsequent works he would return many times to the question of geological and social evolution. [page 87]
Along the way, Biruni discovered the concept of specific gravity to address the issue of substandard gemstones and precious metals being offered in the thriving local market. Later in life, he would write a treatise on the subject. [Page 61]
Biruni also made startlingly modern-sounding comments on such topics as economics.11
Biruni's Masterpiece
This is the title Starr gives to his Chapter 12 (of 19). It refers to a book known simply as India, which, in its modern editions, contains about 700 pages. It covers diverse topics such as “mathematics, astronomy, cultural anthropology, geography, geology, and the comparative study of religions” and derives from the extensive amount of time Biruni spent in India. He became enamored of an Indian thinker named Aryabhata, who, among many other things, proposed that the earth rotates daily on its axis. Biruni never quite accepted this idea, although he admitted it was consistent with the mathematics of astronomy.
He learned from Indian travelers to the south that the subcontinent extended below the equator, and he already knew this to be true of Africa. These findings were in direct contradiction to Aristotle and Ptolomy, both of whom held that continents existed only in the northern hemisphere. His newly gained knowledge no doubt contributed to Biruni’s speculation that there might be continents on the other side of the earth.
He implies, but does not state, that the "messengers" that cause the population of animals or other organisms to plummet and thereby reestablish demographic balances are epidemics and natural disasters. Whether due to limitations of time or to fear of offending the religiously orthodox, ln India Biruni does not pursue further the question of geological cataclysm or of the destruction of species through overpopulation. But he shows beyond doubt that he was closely attuned to the kind of evidence that would later lead evolutionary geologists like Humboldt, biologists like Darwln, and demographic pioneers like Malthus to their epochal findings. In fact, Biruni directly presaged these scientists' provocative contributions to human understanding. [page 110]
Ibn Sina’s Masterpiece
Although there was much overlap in the topics about which these two scholars wrote, Biruni tended to focus on the physical sciences, and Ibn Sina on medicine, the law, and metaphysics.
Ibn Sina’s writings on, and reinterpretation of, Aristotle attracted the attention of Christian theologians, but the work he is most remembered for is his Canon of Medicine. In this huge book, he attempted to collect all that was known about medical practice, culling from all known sources on the subject. He also added his own wisdom, influenced by his own experience as a physician, and enhanced by his knowledge of his contemporary world. He wrote, for example, on “curative uses for spices that grow on the warmer shores of the Indian Ocean.“12
Starr points out that Ibn Sina drew heavily from Razi’s work13 (one of the scientists in the UN sculpture pictured earlier). However, Starr goes on to point out that Razi’s work was confined to physical matters, whereas Ibn Sina added much in the way of philosophy.
As long as is this post (and its footnotes), it can give only a sampling of the rich content of this book. Unfortunately, Starr ends his book [pages 221 to the end] on a rather sour note (to me). Pfeifer’s essay, referenced earlier, offers a sharp criticism of Starr’s views for what are perhaps some of the same reasons.
Pfeifer accuses Starr (and I agree) of demeaning Muslim culture and portraying Arabs and others as being bloodthirsty conquerors (as if European civilization could claim to be otherwise). His section on laws, governance, and rulers reveals a complete ignorance (or exclusion) of Native American and other indigenous cultures.
For all its shortcomings, however, this book is highly revelatory, and well worth (to me) the time to learn about the incredible variety of intellectual development that was underway in this part of the world during the European “Dark Ages” (usually thought of as extending from about 500 to 1500 in the Current Era).
FOOTNOTES
There is no commonly-accepted dating of the Golden Age, some scholars advocate for a shorter period, some for a longer one. In almost all cases, however, the eleventh-century events covered in this post are included in the Islamic Golden Age timeline.
See footnote 13 for more on this issue of sourcing.
[page 17] (page numbers in footnotes and quotations refer to the Oxford University Press book featured in this post; The Genius of Their Age)
Starr dedicates his Chapter 15 to a commentary on Biruni’s Canon for Masud, which, among other things, ridiculed the idea that the earth is flat and also the predictions made by astrologists. At the end of the chapter, Starr quotes George Sarton (1884-1956) as saying that Biruni was “one of the very greatest scientists of Islam and, all things considered, one of the greatest of all times.”
Ahmed, Akbar S. (1984). "Al-Beruni: The First Anthropologist". RAIN (60). Royal Anthropological Institute of Great Britain and Ireland: 9–10. doi:10.2307/3033407. JSTOR 3033407.
Columbus certainly must have had a compass, but that would have told him only his direction of travel, not his latitude. He left from a point on latitude 28, and he maintained that line as he sailed westward. being unaware, evidently, of the concept of Great Circular distance (that the shortest route between two points on the same latitude is an arc illustrated by placing a string on a globe). The first land he encountered was (probably) San Salvador in the Bahamas, at latitude 24.
The quadrant (one quarter of a circle) astrolabe used by Columbus was difficult to use on a moving ship, especially in rough waters. It was later (in the 1730s) replaced by the more accurate sextant (one-sixth of a circle).
The astrolabe caused a stir when it became known to 12th-century Western Europeans; Abelard and Heloise named their son ‘Astrolabe’ in admiration. Two centuries later, Chaucer wrote a technical treatise on the instrument for his ten-year-old son Lewis, who had a particular ‘abilite to lerne sciences touching nombres and proporciouns’. Chaucer gave him an astrolabe to practise with, set up for use at the latitude of Oxford. He took it for granted that ‘every discret persone’ would want to know how to use ‘so noble an instrument’. The device was intriguing because it allowed users to make calculations about not only the present but also the future movements of the universe. Throughout the Middle Ages there was considerable learned curiosity in the capacity of the planets to influence human behaviour. The twelve signs of the zodiac could be made to correspond to the health of different parts of the body, to the rising and falling of fortune, and held out the promise – ‘blasphemous nonsense’, according to Augustine – of revealing what was to come.
For all their technical sophistication, both sundials and astrolabes relied on a clear view of the skies: the future of the universe could be obscured by something as evanescent as a cloud.
from an article in the London Review of Books (19 October 2023) on the development of mechanical clocks. Both Biruni and Ibn Sina wrote scathing critiques of the humbuggery of astrologers, while at the same time finding useful the celestial data that astrologers collected.
Starr mentions [page 221] that “North and South America were later discovered.” The peoples who had been living there for thousands of years should probably be credited with having “discovered” those continents. ;)
[page 91] the potential error is given as 72 miles for a tiny error in the value of the cosine of the angle he was measuring. His actual error was only 21.51 miles, just .003 percent of the modern number. Starr goes on to say
His measurement of the earth opened the way to similarly precise measurements of the distance between longitudes, the size of continents, and the distances between two points too distant from one another to be measured by more conventional means. It was the single most momentous act of discovery in in the fields of geography and geodesy up to that time. [emphasis added]
Eratosthenes’s estimate was approximately 252,000 stadia (39,060 to 40,320 kilometres {24,270 to 25,050 miles} or an error of about one or two percent [190 to 590 miles] compared with the modern value of 24,860 miles). The distance values are given as a range because it is not known precisely how long a stadion was in terms of our modern metrics.
[page 176] Biruni argues that human beings are by nature unequal. … The advent of money provided a measure of wealth in general and of inequality in particular. Humans, he argues, are also highly individualistic. Differences in people's abilities brought variations in wealth. … Biruni rails against inherited wealth and privilege … the withdrawal of wealth from circulation impoverishes society, which cannot exist without the productive exchange of goods and services. To preserve themselves from dangers posed by their environment, people had to band together and collaborate. The sciences arose not just from some inborn quest for knowledge but as a means of addressing the practical needs of existence. Labor, when voluntary, gave rise to the arts and industries.
[page 86] Human beings, he writes, are social animals, and the division of labor among them is inevitable. But since labor and needs are not in balance, they are valued differently. Mankind therefore developed systems for pricing labor and goods based on the cost of rare metals and jewels. Prices are thereby set on the just basis of the labor involved," which even thieves and oppressors acknowledge. Adam Smith, David Ricardo, and Karl Marx would all have applauded this pioneering expression of the "labor theory of value."
from an essay in the London Review of Books, 7 November 2024, by Laleh Khalili on the importance of the Indian Ocean in world commerce. Using Ibn Sina’s Latinized name Avicenna, she mentioned his work while describing the spice trade.
Cargoes traded across the Indian Ocean before the 17th century include spices, aromata, precious resins, fine gems and gold, along with more mundane primary commodities such as timber and copper, and man-made products: textiles, pottery, porcelain and glass. Among all these, spices most significantly shaped the politics of trade. The Periplus of the Erythraean Sea records the Roman taste for black pepper, which led to trade with merchants on the Malabar Coast. Avicenna’s 11th-century Canon of Medicine describes many curative uses for spices that grow on the warmer shores of the Indian Ocean.
Ibn Sina's disparagement of Razi seems to have arisen from seeing him as a rival and threat. Though Razi had died half a century before Ibn Sina's birth, he looms over the Canon like a specter.
Ibn Sina labored mightily to make his own medical study an alternative to Razi's work and not a mere supplement to it. He clearly succeeded. Yet it was inevitable that Ibn Sina would draw heavily from Razi, as well as from Majusi and other authors going back to Galen. This, after all, was common practice in an era when borrowings were both common and rarely acknowledged.
Even in the West the concept of deliberate plagiarism (from the Latin plagiarius, or "kidnapper") did not elicit general condemnation until recently and even remains legal in most countries. A definitive estimation of the extent of Ibn Sina's borrowings from Razi would require thousands of close comparisons. However, it is difficult to avoid the conclusion that Ibn Sina's general failure to acknowledge the existence of Razi's Comprehensive belies his profound indebtedness to his predecessor. [page 121]
This last paragraph points the way to a rabbit hole that I hope to explore in a future post. The idea of intellectual property is a complex one; in general, I’m an advocate for open source everything, because there is seldom a case to be made for a fully original idea (cf. the earlier quote from Newton). All of this ties in with my opposition to capitalism. Enough said for now…