Ibn al-Haytham

Father of modern optics and pioneer of the scientific method

He is sometimes described as the world's "first true scientist" for his early advocacy of hypothesis testing through experiments and mathematical reasoning.^[1] This figure is called "the father of modern optics" and notably advanced understanding of optics and how people see.^[2]

Last updated 2026-09-30 from the source article.

Quick Facts

Born

0965, 965 (c. 354 AH)

Birthplace

Basra, Buyid Emirate

Died

1040, 1040 (c. 430 AH) (aged around 75)

Place of death

Cairo, Fatimid Caliphate

Field

Physics
mathematics
astronomy

Facts from the source article.

Life and work

After failing to fulfill a task for Caliph Al-Hakim, he was forced into hiding until the caliph's death in 1021, during which he wrote his influential Book of Optics.^[3] His early background involved religious study and community service, but he later chose to move away from religious involvement.^[4] In Basra, he served as a vizier and gained renown for his applied mathematics, demonstrated by his project to control Nile flooding.^[4] His seven-volume Book of Optics, composed between 1011 and 1021, is his most significant work and has come down to us in a Latin version.^[5][6]

He was the first to demonstrate correctly that vision involves light entering the eye (intromission) rather than rays leaving it, and that sight is processed in the brain.^[7] During the Scientific Revolution, his writings were often referenced by Galileo, Descartes, Kepler, and Huygens.^[5]

What the cited sources add

Al-Khalili also notes that while still in Basra, Ibn al-Haytham claimed the Nile's flood waters could be held by dykes and canals to preserve them for summer droughts.^[8] Al-Khalili reports that an expert in Alexandria showed him recently discovered work by Ibn al-Haytham on astronomy.^[8]

References

Wikipedia, "Ibn al-Haytham" (CC BY-SA 4.0), which cites: Haq, Syed (2009). "Science in Islam". Oxford Dictionary of the Middle Ages. . Retrieved 22 October 2014.; Toomer 1964, p. 464; "International Year of Light – Ibn Al-Haytham and the Legacy of Arabic Optics"; Gorini, "Al-Haytham the man of experience. First steps in the science of vision", Journal of the International Society for the History of Islamic Medicine, October 2003, p. 53–55; Al-Khalili, Jim, "The 'first true scientist'", BBC News, 4 January 2009; Roshdi Rashed, Ibn al-Haytham's Geometrical Methods and the Philosophy of Mathemati en.wikipedia.org
Wikipedia, "Ibn al-Haytham" (CC BY-SA 4.0), which cites: Also Alhacen, Avennathan, Avenetan, etc.; the identity of "Alhazen" with Ibn al-Haytham al-Basri "was identified towards the end of the 19th century". ( ); ; Esposito, "The Oxford History of Islam", Oxford University Press, 2000, p. 192; For the description of his main fields, see e.g. ("He is one of the principal Arab mathematicians and, without any doubt, the best physicist.") , ("Ibn al-Ḥayta; Masic, "Ibn al-Haitham--father of optics and describer of vision theory.", Medicinski Arhiv, 2008, p. 183–188; "International Year of Light: Ib en.wikipedia.org
Wikipedia, "Ibn al-Haytham" (CC BY-SA 4.0), which cites: The Prisoner of Al-Hakim. Clifton, NJ: Blue Dome Press, 2017.; Carl Brockelmann, Geschichte der arabischen Litteratur, vol. 1 (1898), p. 469.; "the Great Islamic Encyclopedia", Cgie.org.ir, February 2016 (original not read by us) en.wikipedia.org
Wikipedia, "Ibn al-Haytham" (CC BY-SA 4.0), which cites: Tbakhi, "Ibn Al-Haytham: Father of Modern Optics", Annals of Saudi Medicine, 2007, p. 464–467; . (original not read by us) en.wikipedia.org
Wikipedia, "Ibn al-Haytham" (CC BY-SA 4.0), which cites: Adamson, "Philosophy in the Islamic World: A History of Philosophy Without Any Gaps", UNESCO, 2016, p. 77 (original not read by us) en.wikipedia.org
Wikipedia, "Ibn al-Haytham" (CC BY-SA 4.0), which cites: .; Adamson, "Philosophy in the Islamic World: A History of Philosophy Without Any Gaps", Oxford University Press, 2016, p. 77; Baker 2012, p. 445 (we also read that source) en.wikipedia.org
Wikipedia, "Ibn al-Haytham" (CC BY-SA 4.0), which cites: Adamson, "Philosophy in the Islamic World: A History of Philosophy Without Any Gaps", Oxford University Press, 2016, p. 77; Baker 2012, p. 445; Rashed, "Fermat et le principe du moindre temps", Comptes Rendus Mécanique, 1 April 2019, p. 357–364; Selin 2008, p. 1817; Boudrioua, "Light-Based Science: Technology and Sustainable Development, The Legacy of Ibn al-Haytham", CRC Press, 2017 (we also read that source) en.wikipedia.org
Al-Khalili, Jim, "The 'first true scientist'", BBC News, 4 January 2009. facts only, no text reused. news.bbc.co.uk

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Ibn al-Haytham (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.