Michael H. Brill, Datacolor
We’re not quite at the millennium mark for Alhazen’s Book of Optics. It brings to mind a story of how Alhazen got started in his “second career” that should inspire us all…
A recent Scientific American article  prefaced the results of a photo contest by noting that we are approaching the millennial anniversary (2011) of Persian scientist Ibn al-Haytham’s (Alhazen’s) starting to write his Book of Optics. The article used Alhazen’s discovery of the properties of a magnifying glass as a segue to the wonders of photography through microscopes---and hence to the contest.
Quite apart from the science, one story of that beginning [2, 3, but not 4] has a message to us today. As a civil servant at age 45, Alhazen was called to Egypt by Al-Hakim bi-Amr Allah, the sixth ruler of the Fatimid caliphate, to regulate the flood waters of the Nile. At first Alhazen envisioned a dam where the Aswan now stands, but upon reconnoitering on the south border of Egypt, saw no way to bring that plan to fruition. Quickly realizing his inability, he retired from engineering. In that regime a “severance package” likely would mean your head cut off in a basket. To save his life, Alhazen feigned insanity, and was forthwith held in house arrest from 1011 until al-Hakim died in 1021. Under house arrest, he immediately began his Book of Optics, and thereafter generated many scientific works for the rest of his life (i.e., through 1039).
In the Book of Optics one finds the first modern scientific treatment of optics and vision. Alhazen methodically investigated the magnifying properties of a lens, and also its property as a “burning glass” when focusing the sun’s radiation. He also was the first to project an entire image from outdoors onto a screen indoors through a small hole, and thereby to demonstrate and explain the action of a camera obscura. He had a theory of the Moon illusion (one of many such theories that still mark our landscape). He might have attributed the focusing aspect of a glass lens to the function of the lens of the eye, but the lens’s inversion of the image (which is not evident in vision) was a stumbling block in those days.
One could go on: In the remaining decades of his life, Alhazen contributed to many more areas of science. A geometry problem named after him has stimulated recent publications, and his challenge to Ptolemy’s cosmology was a fitting precursor of the Copernican revolution. Alhazen also described the modern scientific method (usually credited to Francis Bacon). He even noted that a prism splits light into colored components that have different refrangibility---a creditable forerunner of Newton’s work more than 600 years later.
So what encouragement can we take from the example of Alhazen? When confronted by mid-life requirements to reinvent ourselves, we can remember Alhazen’s “retirement” from engineering. Even after a good career goes awry, even after ten years of putative insanity, it is possible to propagate 1000 years of heritage in one’s chosen field.
1. G. Stix, “Illuminating the Lilliputian: 10 Bioscapes Photo Contest winners revealed,” Scientific American, Dec. 2009.
2. Alhazen, Wikipedia.
3. Lorch, Richard (2008), "Ibn al-Haytham", Encyclopædia Britannica.
4. Roshdi Rashed, “A polymath in the 10th century”, Science 297, p. 773 (2002).