Mathematics in Ancient Iraq

A Social History

Eleanor Robson

• Publisher: Princeton University Press
• Year: 2020
• ISBN:
  9780691201405
• Topic: Mathematik
• Subtopic: Geschichte & Philosophie der Mathematik

This monumental book traces the origins and development of mathematics in the ancient Middle East, from its earliest beginnings in the fourth millennium BCE to the end of indigenous intellectual culture in the second century BCE when cuneiform writing was gradually abandoned. Eleanor Robson offers a history like no other, examining ancient mathematics within its broader social, political, economic, and religious contexts, and showing that mathematics was not just an abstract discipline for elites but a key component in ordering society and understanding the world.
The region of modern-day Iraq is uniquely rich in evidence for ancient mathematics because its prehistoric inhabitants wrote on clay tablets, many hundreds of thousands of which have been archaeologically excavated, deciphered, and translated. Drawing from these and a wealth of other textual and archaeological evidence, Robson gives an extraordinarily detailed picture of how mathematical ideas and practices were conceived, used, and taught during this period. She challenges the prevailing view that they were merely the simplistic precursors of classical Greek mathematics, and explains how the prevailing view came to be. Robson reveals the true sophistication and beauty of ancient Middle Eastern mathematics as it evolved over three thousand years, from the earliest beginnings of recorded accounting to complex mathematical astronomy. Every chapter provides detailed information on sources, and the book includes an appendix on all mathematical cuneiform tablets published before 2007.

CHAPTER ONE

Scope, Methods, Sources

The mathematics of ancient Iraq, attested from the last three millennia BCE, was written on clay tablets in the Sumerian and Akkadian languages using the cuneiform script, often with numbers in the sexagesimal place value system (§1.2). There have been many styles of interpretation since the discovery and decipherment of that mathematics in the late nineteenth and early twentieth centuries CE (§1.1), but this book advocates a combination of close attention to textual and linguistic detail, as well as material and archaeological evidence, to situate ancient mathematics within the socio-intellectual worlds of the individuals and communities who produced and consumed it (§1.3).

1.1 THE SUBJECT: ANCIENT IRAQ AND ITS MATHEMATICS

Iraq—Sumer—Babylonia—Mesopotamia: under any or all of these names almost every general textbook on the history of mathematics assigns the origins of ‘pure’ mathematics to the distant past of the land between the Tigris and Euphrates rivers. Here, over five thousand years ago, the first systematic accounting techniques were developed, using clay counters to represent fixed quantities of traded and stored goods in the world’s earliest cities (§2.2). Here too, in the early second millennium BCE, the world’s first positional system of numerical notation—the famous sexagesimal place value system—was widely used (§4.2). The earliest widespread evidence for ‘pure’ mathematics comes from the same place and time, including a very accurate approximation to the square root of 2, an early form of abstract algebra, and the knowledge, if not proof, of ‘Pythagoras’ theorem’ defining the relationship between the sides of a right-angled triangle (§4.3). The best-known mathematical artefact from this time, the cuneiform tablet Plimpton 322, has been widely discussed and admired, and claims have been made for its function that range from number theory to trigonometry to astronomy. Most of the evidence for mathematical astronomy, however, comes from the later first millennium BCE (§8.2), from which it is clear that Babylonian astronomical observations, calculational models, and the sexagesimal place value system all had a deep impact on the later development of Old World astronomy, in particular through the person and works of Ptolemy. It is hardly surprising, then, that ever since its discovery a century ago the mathematics of ancient Iraq has claimed an important role in the history of early mathematics. Seen as the first flowering of ‘proper’ mathematics, it has been hailed as the cradle from which classical Greek mathematics, and therefore the Western tradition, grew. But, as laid out over the course of this book, the mathematical culture of ancient Iraq was much richer, more complex, more diverse, and more human than the standard narratives allow.

The mathematical culture of ancient Iraq was by no means confined to the borders of the nation state as it is constructed today. The name al-‘Iraq (Arabic ‘the river shore’) is first attested about a century after the Muslim conquests of the early seventh century CE,¹ while the lines on modern maps which delimit the territory of Iraq are the outcome of the division of the collapsing Ottoman empire amongst European powers at the end of the First World War. The mathematics of pre-Islamic Iraq, as it has been preserved, was written on small clay tablets in cuneiform writing. Because, as argued here, mathematics was an integral and powerful component of cuneiform culture, for present purposes it will be a useful first approximation to say that cuneiform culture and mathematical culture were more or less co-extensive. The core heartland of the cuneiform world was the very flat alluvial plain between Baghdad and the Gulf coast through which the Tigris and Euphrates flow (figure 1.1). It was known variously in antiquity as Sumer and Akkad, Babylonia, Karduniaš, or simply The Land. The Land’s natural resources were primarily organic: reeds, small riverine trees, and other plant matter, but most importantly the earth itself. Alluvial clay was the all-purpose raw material par excellence, from which almost anything from sickle blades to monumental buildings could be manufactured. Equally, when judiciously managed the soil was prodigiously fertile, producing an abundance of arable crops (primarily barley), as well as grazing lands for herds (sheep and goats but also cattle). Even the wildest of marshlands were home to a rich variety of birds and fish and the all-purpose reeds, second only to clay in their utility. What the south lacked, however, were the trappings of luxury: no structural timber but only date-palms and tamarisks, no stone for building or ornamentation other than small outcrops of soft, dull limestone, and no precious or semi-precious stones at all, let alone any metals, base or precious. All these had to be imported from the mountains to the north, east, and west, in exchange for arable and animal products.

The centre of power shifted north at times, to northern Iraq and Syria east of the Euphrates, known in ancient times as Assyria, Subartu, Mitanni, or the land of Aššur. Life here was very different: rainfall could be counted on for wheat-based agriculture, building stone was abundant, and mountainous sources of timber and metal ores relatively close to hand. Conversely, the dates, tamarisks, and reeds of the south were absent here, as were the marshes with their rich flora and fauna. Overland trade routes ran in all directions, linking northern Iraq with the wider world.²

The fluid peripheries over which these territories had at times direct political control or more often cultural influence expanded and contracted greatly over time. At its maximum extent cuneiform culture encompassed most of what we today call the Middle East: the modern-day states of Turkey, Lebanon, Syria, Israel and the Palestinian areas, Jordan, Egypt, and Iran. Chronologically, cuneiform spans over three thousand years, from the emergence of cities, states, and bureaucracies in the late fourth millennium BCE to the gradual decline of indigenous ways of thought under the Persian, Seleucid, and Parthian empires at around the beginning of the common era. The history of mathematics in cuneiform covers this same long stretch and a similarly wide spread (table 1.1).

The lost world of the ancient Middle East was rediscovered by Europeans in the mid-nineteenth century (table 1.2). Decades before the advent of controlled, stratigraphic archaeology, the great cities of Assyria and Babylonia, previously known only through garbled references in classical literature and the Bible, were excavated with more enthusiasm than skill, yielding vast quantities of cuneiform tablets and objets d’art for Western museums.³ The complexities of cuneiform writing were unravelled during the course of the century too, leading to the decipherment of the two main languages of ancient Iraq: Akkadian, a Semitic precursor of Hebrew and Arabic; and Sumerian, which appeared to have no surviving relatives at all.

In the years before the First World War, as scholars became more confident in their interpretational abilities, the first mathematical cuneiform texts were published.⁴ Written in highly abbreviated and technical language, and using the base 60 place value system, they were at first almost impossible to interpret. Over the succeeding decades François Thureau-Dangin and Otto Neugebauer led the race for decipherment, culminating in the publication of their rival monumental editions, Textes mathématiques babyloniens and Mathematische Keilschrifttexte, in the late 1930s.⁵ By necessity, scholarly work was at that time confined to interpreting the mathematical techniques found in the tablets, for there was very little cultural or historical context into which to place them. For the most part the tablets themselves had no archaeological context at all, or at best could be attributed to a named city and a time-span of few centuries in the early second millennium BCE. The final reports of the huge and well-documented excavations of those decades were years away from publication and nor, yet, were there any reliable dictionaries of Akkadian or Sumerian.

After the hiatus of the Second World War, it was business as usual for the historians of cuneiform mathematics. Otto Neugebauer and Abraham Sachs’s Mathematical cuneiform texts of 1945 followed the paradigm of the pre-war publications, as did Evert Bruins and Marguerite Rutten’s Textes mathématiques de Suse of 1961.⁶ Neugebauer had become such a towering figure that his methodology was followed by his successors in the discipline, though often without his linguistic abilities. Cuneiformists put mathematical tablets aside as ‘something for Neugebauer’ even though he had stopped working on Babylonian mathematics ...