al-Bīrūnī
Abū Rayḥān Muḥammad ibn Aḥmad al-Bīrūnī worked in Khwārazm and then, after Maḥmūd of Ghazna’s conquest of it, at the Ghaznavid court, where he travelled in India and wrote on astronomy, mathematics, geography, mineralogy, chronology and the sciences and religions of India. He belongs to the same broader Arabic scientific culture the The Graeco-Arabic Translation Movement built, two and a half centuries after it began and at its eastern edge rather than in Baghdad itself.
The Tafhīm: astrology as the end of a mathematical curriculum
In 1029, in Ghazna, he wrote the Kitāb al-Tafhīm li-Awāʾil Ṣināʿat al-Tanjīm, the Book of Instruction in the Elements of the Art of Astrology, for a named dedicatee, Rayḥāna bint al-Ḥasan, in catechism form: a numbered sequence of questions and answers. Astrology is not the whole of it. The numbered sequence runs through arithmetic and geometry and a substantial treatment of astronomy before it reaches the astrological material, which begins only at paragraph 347 of the work 1. Astrology is presented as resting on, and answerable to, the same mathematical competence used to fix the positions of the stars.
Whether he believed it
The question of al-Bīrūnī’s own view of astrology’s causal claims does not have a settled answer, and the uncertainty is itself instructive: he is neither the credulous popularizer nor the outright rejecter that a shorter story would prefer.
Contested
At issueDid al-Bīrūnī believe the planets act causally on the sublunary world?
R. Ramsay Wright’s edition of the Tafhīm carries a translator’s note quoting Eduard Sachau, from Sachau’s own preface to his edition of al-Bīrūnī’s India: that al-Bīrūnī’s belief in the action of the planets on the world “may be taken for certain, though he nowhere says so,” on the reasoning that the time and labour he spent studying Greek and Indian astrology would otherwise be hard to account for. Wright sets this beside a direct contrast: al-Bīrūnī’s contemporary Avicenna wrote an explicit treatise refuting astrologers, the Risāla fī Radd al-Munajjimīn, and al-Bīrūnī wrote no equivalent refutation, but also no equivalent defence 1 p. 3, translator's note.
That silence deserves to stand. Writing a technically exhaustive, mathematically serious manual of a discipline is not the same act as declaring it true, and al-Bīrūnī had the vocabulary and the occasion to make such a declaration if he had wanted to. His own terminology elsewhere is reported to distinguish the mathematical science of the stars from the practice of astrological judgment more carefully than most of his contemporaries, a distinction studied in the secondary literature 2; the specialist study of that distinction is listed here as further reading, since it has not been read in full for this entry.
Gap in the evidence
Whether al-Bīrūnī privately accepted astrology’s causal claims, accepted only its predictive utility while doubting its physical rationale, or withheld judgment as a matter of intellectual discipline is argued rather than settled in the scholarship this entry draws on, and no position is asserted here.
Why this belongs beside Abū Maʿshar
Abū Maʿshar a century and a half earlier wrote to expound and extend astrological doctrine. Al-Bīrūnī wrote a manual comprehensive enough to train a reader in the same doctrine while keeping his own verdict on it private. Both postures exist inside the same tradition and the same broader scientific culture, and reporting only one of them would misrepresent the range of stances the The Graeco-Arabic Translation Movement made possible.
References
- al-Bīrūnī, trans. R. Ramsay Wright. The Book of Instruction in the Elements of the Art of Astrology. London: Luzac & Co., 1934 (composed 1029), xviii + 333 pp.. p. 3, translator's note. https://www.skyscript.co.uk/pdf/pubs/texts/albiruni/docs/albiruni.pdf recordprimary source
Reproduces British Museum MS Or. 8349, al-Bīrūnī's own catechism-form textbook of arithmetic, geometry, astronomy and astrology, written in 1029 for Rayḥāna bint al-Ḥasan. Read from this scan, including Wright's translator's note on p. 3 quoting Eduard Sachau's judgment, from Sachau's preface to his edition of al-Bīrūnī's "India", that al-Bīrūnī nowhere states outright whether he believed the planets act on the sublunary world, against which Wright sets the contrast of al-Bīrūnī's contemporary Avicenna, who wrote an explicit refutation of astrologers. Record confirmed against the contemporary review in the Journal of the Royal Asiatic Society, which gives the same pagination.
- Dimitri Gutas. Greek Thought, Arabic Culture: The Graeco-Arabic Translation Movement in Baghdad and Early ʿAbbāsid Society (2nd-4th/8th-10th centuries). Arabic Thought and Culture. London and New York: Routledge, 1998. ISBN 9780415061339 recordscholarly
The standard account of why the translation movement happened, not only that it did: patronage, the Abbasid ideology of universal empire, and the demand for astrology and astronomy as an early driver alongside medicine and philosophy. Paperback ISBN and pagination (xvii + 230 pp.) confirmed against the Cambridge Core review of the 1998 printing; a hardback impression carries ISBN 9780415061322.
Further reading
- Shlomo Pines. The Semantic Distinction between the Terms Astronomy and Astrology according to al-Bīrūnī, 1964.