The Nature of Things & the Display of Information: Alhazen and Optics, 1572

JF Ptak Science Books LLC
Alhazen, (pseudonym of Abu Ali Hasan Ibn al-Haitham), born in Basra, Iraq, and who lived from 965-1039, was perhaps the greatest of all the great Muslim physicists, and was also one of the greatest physicists with an interest in optics of all time. Considered to be “the father of modern optics”, he was an original thinker and an historian, an overall scientist,  preserving the ancient, accentuating the modern and creative in his own right.

The woodcut illustration—deceptively complex but rather simple once you focus-- from his book Opticae thesavrvs. Alhazeni Arabis libri septem, nuncprimum editi. Eivsdem liber De crepvscvlis & nubium ascensionibus… demonstrates a number of optical principles--if you look hard enough. (The Opticae by the way was about the only one of his 200 or so books to have survived the destructive powers of time and neglect.)  In the foreground we see tow examples in the field of optics of keen interest to Alhazen. The man standing in the puddle up to his knees in water shows the distortion that occurs due to refraction (an area in which he greatly improved upon Ptolemy’s understanding) The guy to the right of naked knee-distorted man is probably using his mirror to keep an eye out on what was happening behind him (it looks as though the person he’s spying is not him but someone hiding behind the hillock). This small defensive use of the mirror pales in comparison to what was happening as a cause of mirrors directly behind him: the galleons are definitely being set ablaze by the Archimedean-like use of mirrors in the city on the far side of the harbor (like Syracuse), and we can see that one of the ships is already nearly sunken.

 The bridge (with the loitering elephants ?) is set to exhibit the knowledge of perspective, even though this is not the best example of receding background-- it was through Alhazen that a very considerable part of that science found its way into Medieval and Renaissance culture, particularly in the artwork of  Ghiberti, Alberti, Leonardo, and later, Poussin.  Roger Bacon (13^th c), Pole Witelo (Vitellio) and most of the other Medieval Western writers on optics based their optical work primarily on Alhazen’s work. ' (The use and choice of the elephant on the bridge is a mystery to me, particularly since we don’t see one on the other side of the bridge, which would’ve been helpful to illuminate the perspective bit.)  The rainbow in the background is there simply to remind us of the already well-known association of its formation and light. The setting sun might also hint at Alhazen’s discussion of the density of the atmosphere and the relation between it and  height—he would go on to discover that origin and breadth of twilight, the height of the atmosphere, and many other things back there one thousand years ago. This woodcut hints at only a few of his great achievements.

 

 

Comments

[Bradley Steffens]

Great post about Alhazen! I especially enjoyed your analysis of the woodcut. If your readers would like to know more about Alhazen, I would like to recommend my new book, Ibn al-Haytham: First Scientist. Written for young adults, it is the world's first full biography of the eleventh-century Muslim scholar known in the West as Alhazen or Alhacen.