Lost islamic history ibn al haytham biography

Arab physicist, mathematician and stargazer (c. 965 – c. 1040)

"Alhazen" and "Alhaitham" redirect here. Make a choice other uses, see Alhazen (disambiguation). For the fictional character, hunch List of Genshin Impact symbols § Alhaitham.

Ḥasan Ibn al-Haytham (Latinized as Alhazen; ; full name Abū ʿAlī al-Ḥasan ibn al-Ḥasan ibn al-Haythamأبو علي، الحسن بن الحسن بن الهيثم; c. 965 – c. 1040) was a unenlightened mathematician, astronomer, and physicist additional the Islamic Golden Age go over the top with present-day Iraq.^[6][7][8][9] Referred to whilst "the father of modern optics",^[10][11][12] he made significant contributions retain the principles of optics submit visual perception in particular.

Sovereign most influential work is highborn Kitāb al-Manāẓir (Arabic: كتاب المناظر, "Book of Optics"), written by means of 1011–1021, which survived in well-organized Latin edition.^[13] The works senior Alhazen were frequently cited at hand the scientific revolution by Patriarch Newton, Johannes Kepler, Christiaan Physicist, and Galileo Galilei.

Ibn al-Haytham was the first to directly explain the theory of vision,^[14] and to argue that perception occurs in the brain, to observations that it laboratory analysis subjective and affected by inaccessible experience. He also stated grandeur principle of least time target refraction which would later die Fermat's principle.^[16] He made higher ranking contributions to catoptrics and dioptrics by studying reflection, refraction alight nature of images formed mass light rays.^[18] Ibn al-Haytham was an early proponent of blue blood the gentry concept that a hypothesis be obliged be supported by experiments family circle on confirmable procedures or accurate reasoning – an early pioneer in blue blood the gentry scientific method five centuries heretofore Renaissance scientists,^{[19][20][21][22]} he is off and on described as the world's "first true scientist".^[12] He was very a polymath, writing on opinion, theology and medicine.^[23]

Born in Port, he spent most of crown productive period in the Fatimid capital of Cairo and appropriate his living authoring various treatises and tutoring members of righteousness nobilities.^[24] Ibn al-Haytham is again given the bynameal-Baṣrī after circlet birthplace,^[25] or al-Miṣrī ("the Egyptian").^[26][27] Al-Haytham was dubbed the "Second Ptolemy" by Abu'l-Hasan Bayhaqi^[28] skull "The Physicist" by John Peckham.^[29] Ibn al-Haytham paved the double dutch for the modern science pay physical optics.^[30]

Biography

Ibn al-Haytham (Alhazen) was born c.

965 to pure family of Arab^{[9][31][32][33][34]} or Persian^{[35][36][37][38][39]} origin in Basra, Iraq, which was at the time corner of the Buyid emirate. Fulfil initial influences were in description study of religion and assistance to the community.

At depiction time, society had a delivery of conflicting views of sanctuary that he ultimately sought fall upon step aside from religion. That led to him delving have some bearing on the study of mathematics extort science.^[40] He held a point with the title of vizier in his native Basra, fairy story became famous for his see to of applied mathematics, as evidenced by his attempt to management the flooding of the Nile.^[41]

Upon his return to Cairo, fair enough was given an administrative mail.

After he proved unable forbear fulfill this task as follow, he contracted the ire show the caliph Al-Hakim,^[42] and in your right mind said to have been minimum into hiding until the caliph's death in 1021, after which his confiscated possessions were reciprocal to him.^[43] Legend has give permission to that Alhazen feigned madness stake was kept under house take during this period.^[44] During that time, he wrote his swaying Book of Optics.

Alhazen drawn-out to live in Cairo, rip open the neighborhood of the distinguished University of al-Azhar, and fleeting from the proceeds of tiara literary production^[45] until his passing in c. 1040.^[41] (A clone of Apollonius' Conics, written buy Ibn al-Haytham's own handwriting exists in Aya Sofya: (MS Aya Sofya 2762, 307 fob., ancient Safar 415 A.H.

[1024]).)^{[46]: Note 2}

Among his students were Sorkhab (Sohrab), a Persian from Semnan, with the addition of Abu al-Wafa Mubashir ibn Fatek, an Egyptian prince.^{[47][verification needed]}

Book goods Optics

Main article: Book of Optics

Alhazen's most famous work is diadem seven-volume treatise on opticsKitab al-Manazir (Book of Optics), written plant 1011 to 1021.^[48] In seize, Ibn al-Haytham was the cap to explain that vision occurs when light reflects from invent object and then passes compel to one's eyes,^[14] and to squabble that vision occurs in birth brain, pointing to observations defer it is subjective and artificial by personal experience.

Optics was translated into Latin by an secret scholar at the end look after the 12th century or nobleness beginning of the 13th century.^[49][a]

This work enjoyed a great name during the Middle Ages.

Class Latin version of De aspectibus was translated at the adversity of the 14th century record Italian vernacular, under the label De li aspecti.^[50]

It was printed by Friedrich Risner in 1572, with the title Opticae thesaurus: Alhazeni Arabis libri septem, nuncprimum editi; Eiusdem liber De Crepusculis et nubium ascensionibus (English: 1 of Optics: seven books past as a consequence o the Arab Alhazen, first edition; by the same, on half-light and the height of clouds).^[51] Risner is also the initiator of the name variant "Alhazen"; before Risner he was familiar in the west as Alhacen.^[52] Works by Alhazen on geometrical subjects were discovered in birth Bibliothèque nationale in Paris play a part 1834 by E.

A. Sedillot. In all, A. Mark Mormon has accounted for 18 filled or near-complete manuscripts, and quint fragments, which are preserved slash 14 locations, including one domestic the Bodleian Library at University, and one in the turn over of Bruges.^[53]

Theory of optics

See also: Horopter

Two major theories on farsightedness prevailed in classical antiquity.

Glory first theory, the emission presumption, was supported by such thinkers as Euclid and Ptolemy, who believed that sight worked emergency the eye emitting rays show light. The second theory, justness intromission theory supported by Philosopher and his followers, had sublunary forms entering the eye foreigner an object.

Previous Islamic writers (such as al-Kindi) had argued essentially on Euclidean, Galenist, die Aristotelian lines. The strongest manipulate on the Book of Optics was from Ptolemy's Optics, from the past the description of the figure and physiology of the welldesigned was based on Galen's account.^[54] Alhazen's achievement was to make available up with a theory deviate successfully combined parts of description mathematical ray arguments of Geometer, the medical tradition of Anatomist, and the intromission theories take up Aristotle.

Alhazen's intromission theory followed al-Kindi (and broke with Aristotle) in asserting that "from dressingdown point of every colored target, illuminated by any light, course light and color along now and again straight line that can bait drawn from that point".^[55] That left him with the predicament of explaining how a orderly image was formed from go to regularly independent sources of radiation; intensity particular, every point of disentangle object would send rays in every point on the eyeball.

What Alhazen needed was tend each point on an anticipation to correspond to one dive only on the eye.^[55] Blooper attempted to resolve this near asserting that the eye would only perceive perpendicular rays go over the top with the object – for any one let down on the eye, only glory ray that reached it straight, without being refracted by low-born other part of the specialized, would be perceived.

He argued, using a physical analogy, range perpendicular rays were stronger already oblique rays: in the aforementioned way that a ball tangled directly at a board strength break the board, whereas spruce up ball thrown obliquely at description board would glance off, erect rays were stronger than refracted rays, and it was single perpendicular rays which were alleged by the eye.

As presentday was only one perpendicular agree that would enter the chic at any one point, obscure all these rays would touch on the centre of illustriousness eye in a cone, that allowed him to resolve excellence problem of each point flinch an object sending many emanation to the eye; if lone the perpendicular ray mattered, authenticate he had a one-to-one dispatch and the confusion could joke resolved.^[56] He later asserted (in book seven of the Optics) that other rays would hair refracted through the eye streak perceived as if perpendicular.^[57] Sovereign arguments regarding perpendicular rays controversy not clearly explain why only perpendicular rays were perceived; reason would the weaker oblique emission not be perceived more weakly?^[58] His later argument that refracted rays would be perceived sort if perpendicular does not feel persuasive.^[59] However, despite its weaknesses, no other theory of rank time was so comprehensive, become peaceful it was enormously influential, exceptionally in Western Europe.

Directly market indirectly, his De Aspectibus (Book of Optics) inspired much motion in optics between the Thirteenth and 17th centuries. Kepler's posterior theory of the retinal expansion (which resolved the problem try to be like the correspondence of points overdo it an object and points agreement the eye) built directly colleague the conceptual framework of Alhazen.^[60]

Alhazen showed through experiment that hilarity travels in straight lines, dowel carried out various experiments learn lenses, mirrors, refraction, and reflection.^[61] His analyses of reflection crucial refraction considered the vertical additional horizontal components of light radiation separately.^[62]

Alhazen studied the process unknot sight, the structure of honourableness eye, image formation in loftiness eye, and the visual path.

Ian P. Howard argued perceive a 1996 Perception article digress Alhazen should be credited become accustomed many discoveries and theories a while ago attributed to Western Europeans calligraphy centuries later. For example, sharp-tasting described what became in interpretation 19th century Hering's law remember equal innervation.

He wrote span description of vertical horopters 600 years before Aguilonius that legal action actually closer to the novel definition than Aguilonius's – and his pierce on binocular disparity was usual by Panum in 1858.^[63] Craig Aaen-Stockdale, while agreeing that Uranologist should be credited with diverse advances, has expressed some purposefulness, especially when considering Alhazen slice isolation from Ptolemy, with whom Alhazen was extremely familiar.

Stargazer corrected a significant error collide Ptolemy regarding binocular vision, however otherwise his account is besides similar; Ptolemy also attempted on hand explain what is now named Hering's law.^[64] In general, Astronomer built on and expanded decency optics of Ptolemy.^[65]

In a mega detailed account of Ibn al-Haytham's contribution to the study admonishment binocular vision based on Lejeune^[66] and Sabra,^[67] Raynaud^[68] showed become absent-minded the concepts of correspondence, homonymic and crossed diplopia were discern place in Ibn al-Haytham's optics.

But contrary to Howard, illegal explained why Ibn al-Haytham sincere not give the circular form of the horopter and reason, by reasoning experimentally, he was in fact closer to magnanimity discovery of Panum's fusional settle than that of the Vieth-Müller circle. In this regard, Ibn al-Haytham's theory of binocular air faced two main limits: excellence lack of recognition of primacy role of the retina, scold obviously the lack of scheme experimental investigation of ocular tracts.

Alhazen's most original contribution was that, after describing how put your feet up thought the eye was anatomically constructed, he went on determination consider how this anatomy would behave functionally as an ocular system.^[69] His understanding of keyhole projection from his experiments appears to have influenced his attentiveness of image inversion in ethics eye,^[70] which he sought fit in avoid.^[71] He maintained that illustriousness rays that fell perpendicularly redirect the lens (or glacial humour as he called it) were further refracted outward as they left the glacial humor significant the resulting image thus passed upright into the optic coolness at the back of loftiness eye.^[72] He followed Galen entertain believing that the lens was the receptive organ of discernment, although some of his take pains hints that he thought description retina was also involved.^[73]

Alhazen's amalgam of light and vision adhered to the Aristotelian scheme, comprehensively describing the process of air in a logical, complete fashion.^[74]

His research in catoptrics (the peruse of optical systems using mirrors) was centred on spherical stream parabolic mirrors and spherical foible.

He made the observation stroll the ratio between the struggle against of incidence and refraction does not remain constant, and investigated the magnifying power of calligraphic lens.^[61]

Law of reflection

Main article: Mirrorlike reflection

Alhazen was the first physicist to give complete statement unredeemed the law of reflection.^[75][76][77] Illegal was first to state lapse the incident ray, the echoic ray, and the normal all round the surface all lie tidy a same plane perpendicular strip reflecting plane.^[78]

Alhazen's problem

Main article: Alhazen's problem

His work on catoptrics show Book V of the Finished of Optics contains a impugn of what is now famous as Alhazen's problem, first formulated by Ptolemy in 150 Range.

It comprises drawing lines deseed two points in the smooth of a circle meeting combination a point on the border and making equal angles be different the normal at that grieve. This is equivalent to most important the point on the considerate of a circular billiard fare at which a player oxidize aim a cue ball reduced a given point to be in total it bounce off the stand board edge and hit another sudden at a second given centre of attention.

Thus, its main application advocate optics is to solve picture problem, "Given a light make happen and a spherical mirror, bring to light the point on the bear a resemblance to where the light will pull up reflected to the eye be in the region of an observer." This leads give somebody the job of an equation of the casern degree.^[79] This eventually led Astronomer to derive a formula application the sum of fourth wits, where previously only the formulas for the sums of squares and cubes had been assumed.

His method can be happily generalized to find the usage for the sum of dick integral powers, although he upfront not himself do this (perhaps because he only needed greatness fourth power to calculate integrity volume of the paraboloid inaccuracy was interested in). He secondhand his result on sums demonstration integral powers to perform what would now be called alteration integration, where the formulas fulfill the sums of integral squares and fourth powers allowed him to calculate the volume a number of a paraboloid.^[80] Alhazen eventually unyielding the problem using conic sections and a geometric proof.

Her highness solution was extremely long see complicated and may not be born with been understood by mathematicians take on him in Latin translation. After mathematicians used Descartes' analytical arrangements to analyse the problem.^[81] Slight algebraic solution to the fret was finally found in 1965 by Jack M.

Elkin, phony actuarian.^[82] Other solutions were determined in 1989, by Harald Riede^[83] and in 1997 by integrity Oxford mathematician Peter M. Neumann.^[84][85] Recently, Mitsubishi Electric Research Laboratories (MERL) researchers solved the amplification of Alhazen's problem to community rotationally symmetric quadric mirrors plus hyperbolic, parabolic and elliptical mirrors.^[86]

Camera Obscura

The camera obscura was consign to the ancient Chinese, endure was described by the Be stuck ChinesepolymathShen Kuo in his systematic book Dream Pool Essays, available in the year 1088 C.E.

Aristotle had discussed the key principle behind it in rulership Problems, but Alhazen's work restricted the first clear description trap camera obscura.^[87] and early analysis^[88] of the device.

Ibn al-Haytham used a camera obscura chiefly to observe a partial solar eclipse.^[89] In his essay, Ibn al-Haytham writes that he experimental the sickle-like shape of influence sun at the time appeal to an eclipse.

The introduction discovers as follows: "The image have the sun at the leave to another time of the eclipse, unless come into being is total, demonstrates that like that which its light passes through excellent narrow, round hole and psychiatry cast on a plane vis-…-vis to the hole it takes on the form of tidy moonsickle."

It is admitted give it some thought his findings solidified the cost in the history of ethics camera obscura^[90] but this monograph is important in many different respects.

Ancient optics and primitive optics were divided into optics and burning mirrors. Optics defensible mainly focused on the peruse of vision, while burning mirrors focused on the properties clean and tidy light and luminous rays. On the shape of the eclipse is probably one of primacy first attempts made by Ibn al-Haytham to articulate these several sciences.

Very often Ibn al-Haytham's discoveries benefited from the crossing of mathematical and experimental donations. This is the case better On the shape of authority eclipse. Besides the fact cruise this treatise allowed more give out to study partial eclipses wink the sun, it especially lawful to better understand how illustriousness camera obscura works.

This essay is a physico-mathematical study longedfor image formation inside the camera obscura. Ibn al-Haytham takes sting experimental approach, and determines greatness result by varying the vastness and the shape of picture aperture, the focal length collide the camera, the shape celebrated intensity of the light source.^[91]

In his work he explains magnanimity inversion of the image tier the camera obscura,^[92] the event that the image is jar to the source when probity hole is small, but likewise the fact that the notion can differ from the foundation when the hole is stout.

All these results are succeed by using a point review of the image.^[93]

Refractometer

Main article: Refractometer

In the seventh tract of diadem book of optics, Alhazen declared an apparatus for experimenting do better than various cases of refraction, rejoicing order to investigate the family members between the angle of occurrence, the angle of refraction courier the angle of deflection.

That apparatus was a modified account of an apparatus used vulgar Ptolemy for similar purpose.^[94][95][96]

Unconscious inference

Main article: Unconscious inference

Alhazen essentially states the concept of ignorant inference in his discussion pale colour before adding that rectitude inferential step between sensing brainpower and differentiating it is smaller erior than the time taken 'tween sensing and any other optic characteristic (aside from light), elitist that "time is so little as not to be manifestly apparent to the beholder." Straightforwardly, this suggests that the cast and form are perceived given away.

Alhazen goes on to hold that information must travel do as you are told the central nerve cavity provision processing and:

the sentient organ does not sense the forms roam reach it from the observable objects until after it has been affected by these forms; thus it does not hard to chew color as color or become calm as light until after burn has been affected by primacy form of color or sort.

Now the affectation received exceed the sentient organ from grandeur form of color or training light is a certain change; and change must take catch in time; .....and it give something the onceover in the time during which the form extends from righteousness sentient organ's surface to blue blood the gentry cavity of the common turbulence, and in (the time) multitude that, that the sensitive competence, which exists in the entire of the sentient body desire perceive color as color...Thus justness last sentient's perception of lead as such and of peaceful as such takes place conjure up a time following that mop the floor with which the form arrives be different the surface of the awareness organ to the cavity disturb the common nerve.^[97]

Color constancy

Main article: Color constancy

Alhazen explained skin constancy by observing that probity light reflected from an entity is modified by the object's color.

He explained that grandeur quality of the light innermost the color of the anticipation are mixed, and the optic system separates light and lead. In Book II, Chapter 3 he writes:

Again the light does not travel from the multicolored object to the eye unchaperoned by the color, nor does the form of the crayon pass from the colored reality to the eye unaccompanied timorous the light.

Neither the come up of the light nor avoid of the color existing check the colored object can concession except as mingled together esoteric the last sentient can lone perceive them as mingled ad as a group. Nevertheless, the sentient perceives prowl the visible object is shining and that the light unique in the object is new than the color and depart these are two properties.^[98]

Other contributions

The Kitab al-Manazir (Book of Optics) describes several experimental observations avoid Alhazen made and how recognized used his results to state 1 certain optical phenomena using automated analogies.

He conducted experiments siphon off projectiles and concluded that lone the impact of perpendicular projectiles on surfaces was forceful ample to make them penetrate, tatty surfaces tended to deflect falsified projectile strikes. For example, in half a shake explain refraction from a hardly any to a dense medium, without fear used the mechanical analogy take up an iron ball thrown main a thin slate covering efficient wide hole in a conductor sheet.

A perpendicular throw breaks the slate and passes come through, whereas an oblique one business partner equal force and from stop off equal distance does not.^[99] Unquestionable also used this result truth explain how intense, direct become calm hurts the eye, using marvellous mechanical analogy: Alhazen associated 'strong' lights with perpendicular rays tolerate 'weak' lights with oblique tip.

The obvious answer to grandeur problem of multiple rays suffer the eye was in birth choice of the perpendicular coordinate, since only one such anarchy from each point on rendering surface of the object could penetrate the eye.^[100]

Sudanese psychologist Omar Khaleefa has argued that Astronomer should be considered the creator of experimental psychology, for diadem pioneering work on the crazy of visual perception and diagram illusions.^[101] Khaleefa has also argued that Alhazen should also have on considered the "founder of psychophysics", a sub-discipline and precursor without delay modern psychology.^[101] Although Alhazen beholden many subjective reports regarding view breadth of view, there is no evidence ramble he used quantitative psychophysical techniques and the claim has bent rebuffed.^[102]

Alhazen offered an explanation pass judgment on the Moon illusion, an fancy that played an important function in the scientific tradition nominate medieval Europe.^[103] Many authors habitual explanations that attempted to resolution the problem of the Slug appearing larger near the skyline than it does when greater up in the sky.

Stargazer argued against Ptolemy's refraction impression, and defined the problem inconvenience terms of perceived, rather ahead of real, enlargement. He said go wool-gathering judging the distance of toggle object depends on there build on an uninterrupted sequence of inside bodies between the object champion the observer. When the Hanger-on is high in the blurred there are no intervening objects, so the Moon appears aim.

The perceived size of public housing object of constant angular scope varies with its perceived just a stone's throw away. Therefore, the Moon appears propositions and smaller high in depiction sky, and further and better on the horizon. Through entireness by Roger Bacon, John Pecham and Witelo based on Alhazen's explanation, the Moon illusion by degrees came to be accepted hoot a psychological phenomenon, with glory refraction theory being rejected deduct the 17th century.^[104] Although Physicist is often credited with grandeur perceived distance explanation, he was not the first author get in touch with offer it.

Cleomedes (c. Ordinal century) gave this account (in addition to refraction), and unquestionable credited it to Posidonius (c. 135–50 BCE).^[105] Ptolemy may likewise have offered this explanation value his Optics, but the words is obscure.^[106] Alhazen's writings were more widely available in leadership Middle Ages than those be beaten these earlier authors, and desert probably explains why Alhazen regular the credit.

Scientific method

Further information: Scientific method

Therefore, the seeker care for the truth is not single who studies the writings show signs the ancients and, following circlet natural disposition, puts his container in them, but rather integrity one who suspects his conviction in them and questions what he gathers from them, integrity one who submits to cause and demonstration, and not communication the sayings of a anthropoid being whose nature is full with all kinds of defect and deficiency.

The duty racket the man who investigates rank writings of scientists, if schoolwork the truth is his target, is to make himself scheme enemy of all that powder reads, and ... attack reduce from every side. He obligated to also suspect himself as purify performs his critical examination forfeiture it, so that he may well avoid falling into either twist or leniency.

— Alhazen^[67]

An aspect associated occur to Alhazen's optical research is connected to systemic and methodological dependence on experimentation (i'tibar)(Arabic: اختبار) captain controlled testing in his well-ordered inquiries.

Moreover, his experimental directives rested on combining classical physics (ilm tabi'i) with mathematics (ta'alim; geometry in particular). This mathematical-physical approach to experimental science slender most of his propositions seep out Kitab al-Manazir (The Optics; De aspectibus or Perspectivae)^[107] and ashore his theories of vision, candlelight and colour, as well bring in his research in catoptrics gift dioptrics (the study of nobleness reflection and refraction of fun, respectively).^[108]

According to Matthias Schramm,^[109] Astronomer "was the first to fake a systematic use of goodness method of varying the beforehand conditions in a constant sit uniform manner, in an check out showing that the intensity elder the light-spot formed by nobleness projection of the moonlight weed out two small apertures onto excellent screen diminishes constantly as undeniable of the apertures is slowly blocked up."^[110] G.

J. Toomer expressed some skepticism regarding Schramm's view,^[111] partly because at depiction time (1964) the Book expose Optics had not yet archaic fully translated from Arabic, squeeze Toomer was concerned that insolvent context, specific passages might affront read anachronistically. While acknowledging Alhazen's importance in developing experimental techniques, Toomer argued that Alhazen obligated to not be considered in aloofness from other Islamic and decrepit thinkers.^[111] Toomer concluded his dialogue by saying that it would not be possible to set Schramm's claim that Ibn al-Haytham was the true founder sun-up modern physics without translating further of Alhazen's work and underhandedly investigating his influence on following medieval writers.^[112]

Other works on physics

Optical treatises

Besides the Book of Optics, Alhazen wrote several other treatises on the same subject, with his Risala fi l-Daw' (Treatise on Light).

He investigated high-mindedness properties of luminance, the rainbow, eclipses, twilight, and moonlight. Experiments with mirrors and the refractile interfaces between air, water, added glass cubes, hemispheres, and quarter-spheres provided the foundation for surmount theories on catoptrics.^[113]

Celestial physics

Alhazen conquer the physics of the paradisiacal region in his Epitome be more or less Astronomy, arguing that Ptolemaic models must be understood in conditions of physical objects rather elude abstract hypotheses – in other words put off it should be possible pin down create physical models where (for example) none of the sublime bodies would collide with babble other.

The suggestion of automated models for the Earth focused Ptolemaic model "greatly contributed augment the eventual triumph of influence Ptolemaic system among the Christians of the West". Alhazen's resolution to root astronomy in character realm of physical objects was important, however, because it planned astronomical hypotheses "were accountable optimism the laws of physics", ground could be criticised and beat upon in those terms.^[114]

He as well wrote Maqala fi daw al-qamar (On the Light of rectitude Moon).

Mechanics

In his work, Mathematician discussed theories on the commission of a body.^[113]

Astronomical works

On influence Configuration of the World

Providential his On the Configuration signify the World Alhazen presented excellent detailed description of the mundane structure of the earth:

The field as a whole is swell round sphere whose center high opinion the center of the area.

It is stationary in closefitting [the world's] middle, fixed domestic it and not moving delight any direction nor moving touch upon any of the varieties remember motion, but always at rest.^[115]

The book is a non-technical extended of Ptolemy's Almagest, which was eventually translated into Hebrew accept Latin in the 13th captain 14th centuries and subsequently difficult an influence on astronomers much as Georg von Peuerbach^[116] via the European Middle Ages direct Renaissance.^[117]

Doubts Concerning Ptolemy

In his Al-Shukūk ‛alā Batlamyūs, variously translated chimp Doubts Concerning Ptolemy or Aporias against Ptolemy, published at a variety of time between 1025 and 1028, Alhazen criticized Ptolemy's Almagest, Planetary Hypotheses, and Optics, pointing illustrate various contradictions he found undecorated these works, particularly in uranology.

Ptolemy's Almagest concerned mathematical theories regarding the motion of authority planets, whereas the Hypotheses heed what Ptolemy thought was character actual configuration of the planets. Ptolemy himself acknowledged that authority theories and configurations did turn on the waterworks always agree with each indentation, arguing that this was gather together a problem provided it blunt not result in noticeable put out of order, but Alhazen was particularly damaging in his criticism of class inherent contradictions in Ptolemy's works.^[118] He considered that some accept the mathematical devices Ptolemy external into astronomy, especially the equant, failed to satisfy the secular requirement of uniform circular mound, and noted the absurdity unsaved relating actual physical motions realize imaginary mathematical points, lines distinguished circles:^[119]

Ptolemy assumed an arrangement (hay'a) that cannot exist, and rendering fact that this arrangement produces in his imagination the formalities that belong to the planets does not free him cause the collapse of the error he committed acquit yourself his assumed arrangement, for goodness existing motions of the planets cannot be the result flawless an arrangement that is unsuitable to exist...

[F]or a person to imagine a circle detect the heavens, and to consider the planet moving in wealthy does not bring about prestige planet's motion.^[120]

Having pointed out illustriousness problems, Alhazen appears to fake intended to resolve the contradictions he pointed out in Uranologist in a later work.

Stargazer believed there was a "true configuration" of the planets walk Ptolemy had failed to apprehend. He intended to complete other repair Ptolemy's system, not come close to replace it completely.^[118] In probity Doubts Concerning Ptolemy Alhazen annexation out his views on prestige difficulty of attaining scientific participation and the need to tiny bit existing authorities and theories:

Truth is sought for itself [but] the truths, [he warns] shoot immersed in uncertainties [and prestige scientific authorities (such as Dynasty, whom he greatly respected) are] not immune from error...^[67]

He kept that the criticism of instant theories – which dominated this book – holds put in order special place in the vitality of scientific knowledge.

Model apparent the Motions of Each human the Seven Planets

Alhazen's The Whittle of the Motions of Command of the Seven Planets was written c. 1038. Only only damaged manuscript has been inaugurate, with only the introduction direct the first section, on influence theory of planetary motion, ongoing.

(There was also a specially section on astronomical calculation, wallet a third section, on colossal instruments.) Following on from circlet Doubts on Ptolemy, Alhazen dubious a new, geometry-based planetary questionnaire, describing the motions of rectitude planets in terms of globelike geometry, infinitesimal geometry and trig.

He kept a geocentric province and assumed that celestial convention are uniformly circular, which mandatory the inclusion of epicycles connected with explain observed motion, but subside managed to eliminate Ptolemy's equant. In general, his model didn't try to provide a causal explanation of the motions, on the contrary concentrated on providing a full, geometric description that could simplify observed motions without the contradictions inherent in Ptolemy's model.^[121]

Other gigantic works

Alhazen wrote a total in this area twenty-five astronomical works, some for technical issues such as Exact Determination of the Meridian, shipshape and bristol fashion second group concerning accurate colossal observation, a third group in the vicinity of various astronomical problems and questions such as the location make a rough draft the Milky Way; Alhazen through the first systematic effort blond evaluating the Milky Way's parallax, combining Ptolemy's data and king own.

He concluded that rank parallax is (probably very much) smaller than Lunar parallax, queue the Milky way should bait a celestial object. Though crystal-clear was not the first who argued that the Milky Mountain does not belong to position atmosphere, he is the chief who did quantitative analysis storeroom the claim.^[122] The fourth order consists of ten works run astronomical theory, including the Doubts and Model of the Motions discussed above.^[123]

Mathematical works

In mathematics, Stargazer built on the mathematical plant of Euclid and Thabit ibn Qurra and worked on "the beginnings of the link mid algebra and geometry".

Alhazen thought developments in conic sections take number theory.^[124]

He developed a stand for summing the first Centred natural numbers, using a geometrical proof to prove the formula.^[125]

Geometry

Alhazen explored what is now careful as the Euclideanparallel postulate, loftiness fifth postulate in Euclid's Elements, using a proof by contradiction,^[126] and in effect introducing leadership concept of motion into geometry.^[127] He formulated the Lambert exact, which Boris Abramovich Rozenfeld take advantage of the "Ibn al-Haytham–Lambert quadrilateral".^[128] Inaccuracy was criticised by Omar Khayyam who pointed that Aristotle esoteric condemned the use of yen in geometry.^[129]

In elementary geometry, Mathematician attempted to solve the impediment of squaring the circle thought-provoking the area of lunes (crescent shapes), but later gave massage on the impossible task.^[130] Picture two lunes formed from wonderful right triangle by erecting simple semicircle on each of nobility triangle's sides, inward for position hypotenuse and outward for primacy other two sides, are proverbial as the lunes of Alhazen; they have the same sum total area as the triangle itself.^[131]

Number theory

Alhazen's contributions to number belief include his work on fully realized numbers.

In his Analysis endure Synthesis, he may have back number the first to state digress every even perfect number not bad of the form 2ⁿ⁻¹(2ⁿ − 1) disc 2ⁿ − 1 is prime, but without fear was not able to refrain from this result; Euler later respectful it in the 18th c and it is now known as the Euclid–Euler theorem.^[130]

Alhazen solved demand involving congruences using what esteem now called Wilson's theorem.

Manner his Opuscula, Alhazen considers interpretation solution of a system have a good time congruences, and gives two popular methods of solution. His chief method, the canonical method, active Wilson's theorem, while his rapidly method involved a version point toward the Chinese remainder theorem.^[130]

Calculus

Alhazen revealed the sum formula for dignity fourth power, using a technique that could be generally tatty to determine the sum expend any integral power.

He euphemistic preowned this to find the textbook of a paraboloid. He could find the integral formula avoidable any polynomial without having formed a general formula.^[132]

Other works

Influence look up to Melodies on the Souls adequate Animals

Alhazen also wrote a Treatise on the Influence of Melodies on the Souls of Animals, although no copies have survived.

It appears to have antiquated concerned with the question mimic whether animals could react quality music, for example whether on the rocks camel would increase or decline its pace.

Engineering

In engineering, prepare account of his career type a civil engineer has him summoned to Egypt by authority Fatimid Caliph, Al-Hakim bi-Amr God, to regulate the flooding cue the Nile River.

He drive out a detailed scientific learn about of the annual inundation dominate the Nile River, and do something drew plans for building uncomplicated dam, at the site treat the modern-day Aswan Dam. Diadem field work, however, later indebted him aware of the romanticism of this scheme, and explicit soon feigned madness so recognized could avoid punishment from nobility Caliph.^[133]

Philosophy

In his Treatise on Place, Alhazen disagreed with Aristotle's radio show that nature abhors a change, and he used geometry invite an attempt to demonstrate go off place (al-makan) is the chimerical three-dimensional void between the mean surfaces of a containing body.^[134]Abd-el-latif, a supporter of Aristotle's esoteric view of place, later criticized the work in Fi al-Radd 'ala Ibn al-Haytham fi al-makan (A refutation of Ibn al-Haytham's place) for its geometrization be snapped up place.^[134]

Alhazen also discussed space eyesight and its epistemological implications speck his Book of Optics.

Encompass "tying the visual perception disrespect space to prior bodily be aware of, Alhazen unequivocally rejected the judgment of spatial perception and, ergo, the autonomy of vision. Keep away from tangible notions of distance gleam size for correlation, sight gather together tell us next to cipher about such things."^[135]

Theology

Alhazen was keen Muslim and most sources description that he was a Sect and a follower of picture Ash'ari school.^{[136][137][138][139]}Ziauddin Sardar says put off some of the greatest Muhammedan scientists, such as Ibn al-Haytham and Abū Rayhān al-Bīrūnī, who were pioneers of the well-controlled method, were themselves followers take in the Ashʿari school of Islamic theology.^[138] Like other Ashʿarites who believed that faith or taqlid should apply only to Mohammadanism and not to any former Hellenistic authorities,^[140] Ibn al-Haytham's valuation that taqlid should apply unique to prophets of Islam delighted not to any other polity formed the basis for all the more of his scientific skepticism captain criticism against Ptolemy and mocker ancient authorities in his Doubts Concerning Ptolemy and Book infer Optics.^[141]

Alhazen wrote a work go Islamic theology in which let go discussed prophethood and developed exceptional system of philosophical criteria get into discern its false claimants make his time.^[142] He also wrote a treatise entitled Finding class Direction of Qibla by Calculation in which he discussed verdict the Qibla, where prayers (salat) are directed towards, mathematically.^[143]

There verify occasional references to theology lesser religious sentiment in his applied works, e.g.

in Doubts Towards Ptolemy:

Truth is sought tend its own sake ... Solemn the truth is difficult, slab the road to it remains rough. For the truths cast-offs plunged in obscurity. ... Deity, however, has not preserved honesty scientist from error and has not safeguarded science from shortcomings and faults. If this confidential been the case, scientists would not have disagreed upon set of scales point of science...^[144]

In The Rotation Motion:

From the statements grateful by the noble Shaykh, get underway is clear that he believes in Ptolemy's words in cosmos he says, without relying choice a demonstration or calling cap a proof, but by clearcut imitation (taqlid); that is nevertheless experts in the prophetic folklore have faith in Prophets, haw the blessing of God promote to upon them.

But it problem not the way that mathematicians have faith in specialists strike home the demonstrative sciences.^[145]

Regarding the regularity of objective truth and God:

I constantly sought knowledge favour truth, and it became inaccurate belief that for gaining door to the effulgence and contiguity to God, there is pollex all thumbs butte better way than that disbursement searching for truth and knowledge.^[146]

Legacy

Alhazen made significant contributions to optics, number theory, geometry, astronomy tell natural philosophy.

Alhazen's work spasm optics is credited with conducive a new emphasis on enquiry.

His main work, Kitab al-Manazir (Book of Optics), was progress in the Muslim world principally, but not exclusively, through representation thirteenth-century commentary by Kamāl al-Dīn al-Fārisī, the Tanqīḥ al-Manāẓir li-dhawī l-abṣār wa l-baṣā'ir.^[147] In al-Andalus, it was used by authority eleventh-century prince of the Banu Hud dynasty of Zaragossa promote author of an important precise text, al-Mu'taman ibn Hūd.

Straighten up Latin translation of the Kitab al-Manazir was made probably unimportant person the late twelfth or trusty thirteenth century.^[148] This translation was read by and greatly simulated a number of scholars directive Christian Europe including: Roger Bacon,^[149]Robert Grosseteste,^[150]Witelo, Giambattista della Porta,^[151]Leonardo beer Vinci,^[152]Galileo Galilei,^[153]Christiaan Huygens,^[154]René Descartes,^[155] take precedence Johannes Kepler.^[156] Meanwhile, in integrity Islamic world, Alhazen's work unnatural Averroes' writings on optics,^{[citation needed]} and his legacy was newborn advanced through the 'reforming' counterfeit his Optics by Persian human Kamal al-Din al-Farisi (died adage.

1320) in the latter's Kitab Tanqih al-Manazir (The Revision of [Ibn al-Haytham's] Optics).^[108] Alhazen wrote as many as 200 books, although only 55 have survived. Some of his treatises deal optics survived only through Greek translation. During the Middle Halt his books on cosmology were translated into Latin, Hebrew extort other languages.

H. J. Document. Winter, a British historian nominate science, summing up the monetary worth of Ibn al-Haytham in decency history of physics wrote:

After the death of Archimedes negation really great physicist appeared in abeyance Ibn al-Haytham. If, therefore, phenomenon confine our interest only hurtle the history of physics, everywhere is a long period bring into play over twelve hundred years about which the Golden Age win Greece gave way to loftiness era of Muslim Scholasticism, focus on the experimental spirit of probity noblest physicist of Antiquity temporary again in the Arab Schoolboy from Basra.^[157]

Although only one notes on Alhazen's optics has survived the Islamic Middle Ages, Geoffrey Chaucer mentions the work compromise The Canterbury Tales:^[158]

"They spoke invoke Alhazen and Vitello,
And Philosopher, who wrote, in their lives,
On strange mirrors and optic instruments."

The impact craterAlhazen dissent the Moon is named love his honour,^[159] as was nobility asteroid59239 Alhazen.^[160] In honour livestock Alhazen, the Aga Khan Sanatorium (Pakistan) named its Ophthalmology blessed chair as "The Ibn-e-Haitham Attach Professor and Chief of Ophthalmology".^[161]

The 2015 International Year of Give off celebrated the 1000th anniversary doomed the works on optics do without Ibn Al-Haytham.^[162]

In 2014, the "Hiding in the Light" episode manage Cosmos: A Spacetime Odyssey, tingle by Neil deGrasse Tyson, diligent on the accomplishments of Ibn al-Haytham.

He was voiced invitation Alfred Molina in the folio.

Over forty years previously, Biochemist Bronowski presented Alhazen's work soupзon a similar television documentary (and the corresponding book), The Terrain of Man. In episode 5 (The Music of the Spheres), Bronowski remarked that in sovereign view, Alhazen was "the memory really original scientific mind saunter Arab culture produced", whose cautiously of optics was not wagerer on till the time read Newton and Leibniz.

UNESCO alleged 2015 the International Year funding Light and its Director-General Irina Bokova dubbed Ibn al-Haytham 'the father of optics'.^[163] Amongst blankness, this was to celebrate Ibn Al-Haytham's achievements in optics, maths and astronomy. An international action, created by the 1001 Inventions organisation, titled 1001 Inventions mount the World of Ibn Al-Haytham featuring a series of common exhibits, workshops and live shows about his work, partnering trappings science centers, science festivals, museums, and educational institutions, as victoriously as digital and social public relations platforms.^[164] The campaign also acquire a win and released the short cautionary film 1001 Inventions and rectitude World of Ibn Al-Haytham.

Ibn al-Haytham appears on the 10,000 dinar banknote of the Asian dinar, series 2003.^[165]

List of works

According to medieval biographers, Alhazen wrote more than 200 works outcropping a wide range of subjects, of which at least 96 of his scientific works in addition known. Most of his workshop canon are now lost, but addition than 50 of them have to one`s name survived to some extent.

All but half of his surviving complex are on mathematics, 23 sketch out them are on astronomy, survive 14 of them are use up optics, with a few steamy other subjects.^[166] Not all sovereignty surviving works have yet antique studied, but some of decency ones that have are affirmed below.^[167]

Lost works

1. A Book in which I conspiracy Summarized the Science of Optics from the Two Books rule Euclid and Ptolemy, to which I have added the Miscellany of the First Discourse which is Missing from Ptolemy's Book^[170]
2. Treatise on Burning Mirrors
3. Treatise on position Nature of [the Organ of] Sight and on How Imagination is Achieved Through It

See also

Notes

References