Insights into the Science of Logic


Al-Baṣāʼir al-Nuṣayrīyah (or Nasiriyah) fī ʻilm al-manṭiq (Insights into the science of logic) is a treatise on formal logic by the medieval Iranian scholar and jurist ʻUmar Ibn Sahlan al-Sawi (died circa 1058). The work is written in Arabic and is named after the Seljuk official Nusayr al-Din Mahmud (died 1109 or 1110). There are extensive notes on the text by the Egyptian religious leader Muhammad ʻAbduh (1849‒1905). Following a brief section on definitions, Ibn Sahlan begins his technical coverage of the elements of formal logic with a discussion of categories and the mechanics of syllogistic reasoning. Al-Baṣāʼir forms a part of the history of the influence of Greek philosophy on Islamic thought. Aristotle’s writings on logic provided ground for much debate in intellectual circles in the medieval period, with prominent scholars ranged on all sides. Ibn Sahlan’s critique aligns with the group of scholars who, in general, disagreed with the Greek philosopher. The work is said to have had a formative impact on later philosophers such as al-Suhrawardi (died 1191) and on jurists such as Ibn Taymiyah (died 1328), who discussed syllogistic reasoning in philosophy and in legal judgments. In the 19th century, Muhammad ʻAbduh, the Egyptian religious reformer and innovator, discovered Ibn Sahlan’s book during his sojourn in Beirut. He characterizes the book as lucidly written and explained, but he observes that “there are learned words, terms, and issues which might have been clear to contemporaries but need some clarification and explanation.” To meet this need he annotated the text and updated its terminology. His extensive notes situate Ibn Sahlan in the traditions of Islamic philosophy, comparing him particularly with Ibn Sina (Avicenna). Upon ʻAbduh’s return to Cairo, he argued successfully for inclusion of the work in the curriculum at al-Azhar, the foremost theological school in the Sunni world. It remained in the curriculum for many years. This edition of Al-Baṣāʼir was reviewed and prepared for publication by the editors of the Egyptian government’s Bulaq Press. A variant title, al-Baṣā’ir al-Nuṣayrīyah, calls into question the timeline of Ibn Sahlan’s life and suggests that Ibn Sahlan lived into the 12th century.

Date Created

Subject Date

Publication Information

Bulaq Press, Cairo


Title in Original Language

كتاب البصائر النصيرية في علم المنطق

Type of Item

Physical Description

191 pages ; 29 centimeters


  1. Bayard Dodge, Al-Azhar: A Millennium of Muslim Learning (Washington, DC: Middle East Institute, 1961).
  2. Hossein Ziai, “Ebn Sahlān Sāvajī, Qāżī Zayn-al-Dīn ‘Omar,” in Encyclopaedia Iranica.

Last updated: July 28, 2017