Calculation and Power: Engagement of Astronomers in Water-Management Projects in the Early Islamicate State

This paper examines the role of mathematical and scientific expertise in the socio-political and environmental context of the early Abbasid Caliphate (mid-eighth to mid-ninth century), focusing on how scientific pursuits were influenced by political interests and administrative needs. It specifically studies the work of Aḥmad al-Farghānī, a ninth-century astronomer, and his involvement in civil engineering projects, notably the Nilometer in Cairo and a water-supply canal for the city of al-Jaʿfariyya. While al-Farghānī is traditionally recognised for his theoretical contributions to mathematical astronomy, his civil engineering activities were met with disgrace, contrasting sharply with the esteem of his scholarly work. This disparity highlights differing perceptions of intellectual and practical applications of scientific skills during this period. The study contends that examining these scientific and technological endeavors within the broader socio-political framework of the Abbasid era reveals how political ideologies and administrative priorities shaped scientific initiatives and vice versa. It points to a shift in the role of scientists, who, due to their computational skills, became increasingly involved in projects related to water management, vital for the Mesopotamian economy and infrastructure. This shift, the paper suggests, began with the settlement and agricultural expansion driven by Muslim rulers, which necessitated more sophisticated water distribution systems. The paper investigates the concept of “calculator” as an administrative position, detailing al-Farghānī’s responsibilities and failures in these engineering tasks and analysing archaeological and historical evidence of his canal project. It also explores the economic incentives for such projects, linking the eventual decline in large-scale water engineering to broader urban and demographic changes. By examining the application of mathematical expertise in water engineering projects within the context of environmental challenges, the paper seeks to enhance comprehension of the political epistemology of the Abbasid Caliphate, specifically highlighting how scientific and technological efforts were closely linked to economic goals and territorial expansion.