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Science in medieval Islam, also known as Islamic or Arabic science, is a term used in the history of science to refer to the science developed in the Islamic world prior to the modern era, particularly during what is known as the Islamic Golden Age (dated variously between the 7th and 15th centuries). In the course of the expansion of the Islamic world, Muslim scholars encountered the science, mathematics, and medicine of antiquity through the works of Aristotle, Archimedes, Galen, Ptolemy, Euclid, and others. These works and the important commentaries on them were the wellspring of science during the Medieval period. They were translated into Arabic, the lingua franca of this period; scientists within the Islamic civilization were of diverse ethnicity (a great portion were Persians^[1][2] and Arabs,^[2] in addition to Berbers, Moors and Turks) and diverse religious backgrounds (mostly Muslims,^[3][4][5] in addition to many Christians and Jews,^[6][7] as well as Sabians, Zoroastrians and the irreligious).^[8][9]

Overview

Views of historians and scholars

There are several different views on Islamic science among historians of science. The traditionalist view, as exemplified by Bertrand Russell,^[10] holds that Islamic science, while admirable in many technical ways, lacked the intellectual energy required for innovation and was chiefly important as a preserver of ancient knowledge and transmitter to medieval Europe. The revisionist view, as exemplified by Abdus Salam,^[11] George Saliba^[12] and John M. Hobson^[13] holds that a Muslim scientific revolution occurred during the Middle Ages,^[14][15] an expression with which scholars such as Donald Routledge Hill and Ahmad Y Hassan express the view that Islam was the driving force behind the Muslim achievements,^[16] while Robert Briffault even sees Islamic science as the foundation of modern science.^[17] The most prominent view in recent scholarship, however, as exemplified by Toby E. Huff,^[18][19] Will Durant,^[20] Fielding H. Garrison,^[21] Muhammad Iqbal,^[22] Hossein Nasr and Bernard Lewis,^[23] holds that Muslim scientists did help in laying the foundations for an experimental science with their contributions to the scientific method and their empirical, experimental and quantitative approach to scientific inquiry, but that their work cannot be considered a Scientific Revolution,^[18] like that which occurred in early modern Europe and led to the emergence of modern science,^[24][25] with the exception of Ibn al-Haytham's Book of Optics which is widely considered a revolution in the fields of optics and visual perception.^{[26][27][28][29][30][31]}

Rise

During the early Muslim conquests, the Muslim Rashidun army, led primarily by Khalid ibn al-Walid, conquered the Sassanid Persian Empire and more than half of the Byzantine Roman Empire, establishing the caliphate across the Middle East, Central Asia, and North Africa, followed by further expansions across the northwestern Indian subcontinent, southern Italy and the Iberian Peninsula. As a result, the Islamic governments inherited the knowledge and skills of the ancient Middle East, of Greece, of Persia and of India.^[32]

The art of papermaking was obtained from two Chinese prisoners at the Battle of Talas (751), from where it was taken to Samarkand and Baghdad. The Arabs improved upon the Chinese techniques using linen rags instead of mulberry bark.

Most notable Arab scientists and Iranian scientists lived and practiced during the Islamic Golden Age, though not all scientists in Islamic civilization were Arab or Muslim. Some argue that the term "Arab-Islamic" does not appreciate the rich diversity of eastern scholars who have contributed to science in that era.^[33]

During the Islamic Golden Age, Muslim scholars made significant advances in science, mathematics, medicine, astronomy, engineering, and many other fields. During this time, early Islamic philosophy developed and was often pivotal in scientific debates — key figures were usually scientists and philosophers.

The number of important and original Arabic works written on the mathematical sciences is much larger than the combined total of Latin and Greek works on the mathematical sciences.^[34]

Scientific institutions

A number of important institutions previously unknown in the ancient world have their origins in the medieval Islamic world, with the most notable examples being: the public hospital (which replaced healing temples and sleep temples)^[35] and psychiatric hospital,^[36] the public library, the academic degree-granting university, the astronomical observatory as a research institute^[35] (as opposed to a private observation post as was the case in ancient times),^[37] and the trust (Waqf).^[38][39]

The first universities which issued diplomas were the Bimaristan medical university-hospitals of the medieval Islamic world, where medical diplomas were issued to students of Islamic medicine who were qualified to be practicing doctors of medicine from the 9th century. Sir John Bagot Glubb wrote:^[40]

"By Mamun's time medical schools were extremely active in Baghdad. The first free public hospital was opened in Baghdad during the Caliphate of Haroon-ar-Rashid. As the system developed, physicians and surgeons were appointed who gave lectures to medical students and issued diplomas to those who were considered qualified to practice. The first hospital in Egypt was opened in 872 AD and thereafter public hospitals sprang up all over the empire from Spain and the Maghrib to Persia."

The Guinness Book of World Records recognizes the University of Al Karaouine in Fez, Morocco as the oldest university in the world with its founding in 859.^[41] Al-Azhar University, founded in Cairo, Egypt in the 10th century, offered a variety of academic degrees, including postgraduate degrees, and is often considered the first full-fledged university.

A number of distinct features of the modern library were introduced in the Islamic world, where libraries not only served as a collection of manuscripts as was the case in ancient libraries, but also as a public library, a centre for the instruction and spread of sciences and ideas, a place for meetings and discussions, and sometimes as a lodging for scholars or boarding school for pupils.^{[citation needed]} The concept of the library catalog was also introduced in medieval Islamic libraries, where books were organized into specific genres and categories.^[42]

A large number of Muslim polymaths or "universal geniuses", scholars who contributed to many different fields of knowledge were active during the Islamic Golden Age. Muslim polymaths were known as "Hakeems" and they had a wide breadth of knowledge in many different fields of religious and secular learning, comparable to the later "Renaissance Men", such as Leonardo da Vinci, of the European Renaissance period. Polymath scholars were so common during the Islamic Golden Age that it was rare to find a scholar who specialized in any single field at the time.^[43] Notable Muslim polymaths included al-Biruni, al-Jahiz, al-Kindi, Abu Bakr Muhammad al-Razi, Ibn Sina, al-Idrisi, Ibn Bajja, Ibn Zuhr, Ibn Tufayl, Ibn Rushd, al-Suyuti^[44] Jābir ibn Hayyān, al-Khwarizmi, the Banū Mūsā, Abbas Ibn Firnas, al-Farabi, al-Masudi, al-Muqaddasi, Alhacen, Omar Khayyám, al-Ghazali, al-Khazini, Avempace, al-Jazari, Ibn al-Nafis, Nasīr al-Dīn al-Tūsī, Ibn al-Shatir, Ibn Khaldun, and Taqi al-Din, among many others.^[43]

Decline

Islamic science and the numbers of Islamic scientists were traditionally believed to have begun declining from the 12th or 13th centuries. It was believed that, though the Islamic civilization would still produce scientists, that they became the exception, rather than the rule (see List of Islamic scholars). Recent scholarship, however, has come to question this traditional picture of decline, pointing to continued astronomical activity as a sign of a continuing and creative scientific tradition through to the 16th century, of which the work of Ibn al-Shatir (1304–1375) in Damascus is considered the most noteworthy example.^[45][46] This was also the case for other areas of Islamic science, such as medicine, exemplified by the works of Ibn al-Nafis and Şerafeddin Sabuncuoğlu, and the social sciences, exemplified by Ibn Khaldun's Muqaddimah (1370), which itself points out that science was declining in Iraq, Al-Andalus and Maghreb, but continuing to flourish in Persia, Syria and Egypt.^[47]

One reason given for the scientific decline was when the orthodox Ash'ari school of theology challenged the more rational Mu'tazili school of theology, with al-Ghazali's The Incoherence of the Philosophers (Tahafut al-falasifa) being the most notable example. This interpretation was introduced by the Hungarian Orientalist Ignaz Goldziher, who believed that there was an intrinsic antagonism between Islamic orthodoxy and the Greek-influenced traditions of science.^[48] Recent scholarship has questioned this traditional view, however, with a number of scholars pointing out that the Ash'ari school supported science but were only opposed to speculative philosophy and that some of the greatest Muslim scientists such as Alhazen, Biruni, Ibn al-Nafis and Ibn Khaldun were themselves followers of the Ash'ari school.^[44][47] Emilie Savage-Smith also pointed out that Al-Ghazali's positive views towards medicine, particularly anatomy, were a source of encouragement for the increased use of dissection by Muslim physicians (such as Avenzoar and Ibn al-Nafis) in the 12th and 13th centuries.^[49]

Other reasons for the decline of Islamic science include conflicts between the Sunni and Shia Muslims, and invasions by Crusaders and Mongols on Islamic lands between the 11th and 13th centuries, especially the Mongol invasions of the 13th century. The Mongols destroyed Muslim libraries, observatories, hospitals, and universities, culminating in the destruction of Baghdad, the Abbasid capital and intellectual centre, in 1258, which is traditionally understood to have marked an end to the Islamic Golden Age.^[50]

From the 13th century, some traditionalist Muslims believed that the Crusades and Mongol invasions may have been a divine punishment from God against Muslims deviating from the Sunnah, a view that was held even by the famous polymath Ibn al-Nafis.^[51] Such traditionalist views as well as numerous wars and conflicts at the time are believed to have created a climate which made Islamic science less successful than before. However, Y. Ziedan has pointed out that the sack of Baghdad in 1258 was followed by intense scientific activity across Damascus and Cairo, as many Muslim scholars wrote huge encyclopedias (including an 80-volume medical encyclopedia by Ibn al-Nafis) in an attempt to preserve the scientific heritage of the Islamic world and cope with the loss of Baghdad.^[52]

Another reason given for the decline of Islamic science is the disruption to the cycle of equity based on Ibn Khaldun's famous model of Asabiyyah (the rise and fall of civilizations), which points to the decline being mainly due to political and economic factors rather than religious factors.^[47] With the fall of Islamic Spain in 1492, the scientific and technological initiative had long been assumed by the Europeans who laid the foundations for Europe's Renaissance and Scientific Revolution.^[53]

Influence on European science

Medieval European scholars who were active in advancing scientific understanding in Europe often borrowed from or relied upon Muslim works, especially in Islamic Spain and Sicily. These scholars translated scientific and philosophical texts from Arabic into Latin.

In Spain, numerous works were translated by Gerard of Cremona. His translations of Avicenna and works of other Arab physicians introduced Arabic medical and metaphysical texts into Ireland by the 14th century.^[54] He translated Muhammad ibn Mūsā al-Khwārizmī's On Algebra and Almucabala, Jabir ibn Aflah's Elementa astronomica,^[55] al-Kindi's On Optics, Ahmad ibn Muhammad ibn Kathīr al-Farghānī's On Elements of Astronomy on the Celestial Motions, al-Farabi's On the Classification of the Sciences,^[56] the chemical and medical works of Razi,^[57] the works of Thabit ibn Qurra and Hunayn ibn Ishaq,^[58] His translation of Ibn al-Haytham Book of Optics, though it lacked al-Haytham's chapters on radiation and color, became the single most important foundation of the optics of the Latin West.^[59]

Other Arabic works translated into Latin during the 12th century include the works of Muhammad ibn Jābir al-Harrānī al-Battānī and Muhammad ibn Mūsā al-Khwārizmī (including The Compendious Book on Calculation by Completion and Balancing),^[55] the works of Abu al-Qasim (including the al-Tasrif),^[60] Muhammad al-Fazari's Great Sindhind (based on the Surya Siddhanta and the works of Brahmagupta),^[61] the works of Razi and Avicenna (including The Book of Healing and The Canon of Medicine),^[62] the works of Averroes,^[60] the works of Thabit ibn Qurra, al-Farabi, Ahmad ibn Muhammad ibn Kathīr al-Farghānī, Hunayn ibn Ishaq, and his nephew Hubaysh ibn al-Hasan,^[63] the works of al-Kindi, Abraham bar Hiyya's Liber embadorum, Ibn Sarabi's (Serapion Junior) De Simplicibus,^[60] the works of Qusta ibn Luqa,^[64]

the works of Nur Ed-Din Al Betrugi, including On the Motions of the Heavens,^[57][65] Ali ibn Abbas al-Majusi's medical encyclopedia, The Complete Book of the Medical Art,^[57] Abu Mashar's Introduction to Astrology,^[66] the works of Maimonides, Ibn Zezla (Byngezla), Masawaiyh, Serapion, al-Qifti, and Albe'thar.^[67] Abū Kāmil Shujā ibn Aslam's Algebra,^[55] the chemical works of Jābir ibn Hayyān, and the De Proprietatibus Elementorum, an Arabic work on geology written by a pseudo-Aristotle.^[57] By the beginning of the 13th century, Mark of Toledo translated the Qur'an and various medical works.^[68]

Starting in 1210, Arabic texts came to be translated into Hebrew, consisting of scientific works of ancient Greek and medieval Muslim thinkers. By the 14h century, these texts enabled Jews who only read Hebrew to study Aristotelian science. Averroes' commentaries on the Aristotelian corpus was the main source of learning in Hebrew at that time.^[69]

Fibonacci presented the first complete European account of the Hindu-Arabic numeral system from Arabic sources in his Liber Abaci (1202).^[57] Al-Khazini's Zij as-Sanjari was translated into Greek by Gregory Choniades in the 13th century and was studied in the Byzantine Empire.^[70] The astronomical corrections to the Ptolemaic model made by al-Battani and Averroes and the non-Ptolemaic models produced by Mo'ayyeduddin Urdi (Urdi lemma), Nasīr al-Dīn al-Tūsī (Tusi-couple) and Ibn al-Shatir were later adapted into the Copernican heliocentric model. Al-Kindi's (Alkindus) law of terrestrial gravity influenced Robert Hooke's law of celestial gravity, which in turn inspired Newton's law of universal gravitation. Abū al-Rayhān al-Bīrūnī's Ta'rikh al-Hind and Kitab al-qanun al-Mas’udi were translated into Latin as Indica and Canon Mas’udicus respectively. Ibn al-Nafis' Commentary on Compound Drugs was translated into Latin by Andrea Alpago (died 1522), who may have also translated Ibn al-Nafis' Commentary on Anatomy in the Canon of Avicenna, which first described pulmonary circulation and coronary circulation, and which may have had an influence on Michael Servetus, Realdo Colombo and William Harvey.^[71] Translations of the algebraic and geometrical works of Ibn al-Haytham, Omar Khayyám and Nasīr al-Dīn al-Tūsī were later influential in the development of non-Euclidean geometry in Europe from the 17th century.^[72][73] Ibn Tufail's Hayy ibn Yaqdhan was translated into Latin by Edward Pococke in 1671 and into English by Simon Ockley in 1708 and became "one of the most important books that heralded the Scientific Revolution."^[74] Ibn al-Baitar's Kitab al-Jami fi al-Adwiya al-Mufrada also had an influence on European botany after it was translated into Latin in 1758.^[75]

Scientific method

Muslim scientists placed a greater emphasis on experimentation than previous ancient civilizations (for example, Greek philosophy placed a greater emphasis on rationality rather than empiricism),^[17][20] which partly arose from the emphasis on empirical observation found in the Qur'an and Sunnah,^{[76][77][78][79]} and the rigorous historical methods established in the science of hadith.^[76] In addition, there was greater emphasis on combining theory with practice in the Islamic world, where it was common for those studying the sciences to be artisans as well, something that was "considered an aberration in the ancient world",^[80] thus Islamic experts in the sciences were usually expert makers of instruments that would enhance their powers of observation and calculation.^[80] Muslim scientists thus combined precise observation, controlled experiment and careful records^[20] with a new^[17] approach to scientific inquiry which led to the development of the scientific method.^[81] In particular, the empirical observations and experiments of Ibn al-Haytham (Alhacen) in his Book of Optics (1021) is seen as the beginning of the modern scientific method, which he first introduced to optics and psychology. Rosanna Gorini writes:

"According to the majority of the historians al-Haytham was the pioneer of the modern scientific method. With his book he changed the meaning of the term optics and established experiments as the norm of proof in the field. His investigations are based not on abstract theories, but on experimental evidences and his experiments were systematic and repeatable."^{[81][page needed]}

Other early experimental methods were developed by Jābir ibn Hayyān (for chemistry), Muhammad al-Bukhari (for history and the science of hadith),^[76] Al-Kindi (for the Earth sciences),^[82] Avicenna (for medicine), Abū Rayhān al-Bīrūnī (for astronomy and mechanics),^[83] Ibn Zuhr (for surgery)^[84] and Ibn Khaldun (for the social sciences).^[2] The most important development of the scientific method, the use of experimentation and quantification to distinguish between competing scientific theories set within a generally empirical orientation, was introduced by Muslim scientists.

Ibn al-Haytham, a pioneer of modern optics,^[85] used the scientific method to obtain the results in his Book of Optics. In particular, he combined observations, experiments and rational arguments to show that his modern intromission theory of vision, where rays of light are emitted from objects rather than from the eyes, is scientifically correct, and that the ancient emission theory of vision supported by Ptolemy and Euclid (where the eyes emit rays of light), and the ancient intromission theory supported by Aristotle (where objects emit physical particles to the eyes), were both wrong.^[86][87] It is known that Roger Bacon was familiar with Ibn al-Haytham's work and built his optical theories on it; the same with Witelo. Ibn al-Haytham is featured on the 10,000 Iraqi dinar note.

Ibn al-Haytham developed rigorous experimental methods of controlled scientific testing in order to verify theoretical hypotheses and substantiate inductive conjectures.^[88] Ibn al-Haytham's scientific method was similar to the modern scientific method in that it consisted of the following procedures:^[89]

1. Observation
2. Statement of problem
3. Formulation of hypothesis
4. Testing of hypothesis using experimentation
5. Analysis of experimental results
6. Interpretation of data and formulation of conclusion
7. Publication of findings

The development of the scientific method is considered^{[by whom?]} to be fundamental to modern science and some — especially philosophers of science and practicing scientists — consider earlier inquiries into nature to be pre-scientific. Some consider Ibn al-Haytham to be the "first scientist" for this reason.^[90]

In The Model of the Motions, Ibn al-Haytham also describes an early version of Occam's razor, where he employs only minimal hypotheses regarding the properties that characterize astronomical motions, as he attempts to eliminate from his planetary model the cosmological hypotheses that cannot be observed from Earth.^[91]

Robert Briffault wrote in The Making of Humanity:

"The debt of our science to that of the Arabs does not consist in startling discoveries or revolutionary theories; science owes a great deal more to Arab culture, it owes its existence. The ancient world was, as we saw, pre- scientific. The astronomy and mathematics of the Greeks were a foreign importation never thoroughly acclimatized in Greek culture. The Greeks systematized, generalized and theorized, but the patient ways of investigation, the accumulation of positive knowledge, the minute methods of science, detailed and prolonged observation, experimental inquiry, were altogether alien to the Greek temperament. [...] What we call science arose in Europe as a result of a new spirit of inquiry, of new methods of investigation, of the method of experiment, observation, measurement, of the development of mathematics in a form unknown to the Greeks. That spirit and those methods were introduced into the European world by the Arabs."^{[17][page needed]}

Science is the most momentous contribution of Arab civilization to the modern world, but its fruits were slow in ripening. Not until long after Moorish culture had sunk back into darkness did the giant to which it had given birth, rise in his might. It was not science only which brought Europe back to life. Other and manifold influences from the civilization of Islam communicated its first glow to European life."^[92]

George Sarton wrote in the Introduction to the History of Science:

"The main, as well as the least obvious, achievement of the Middle Ages was the creation of the experimental spirit and this was primarily due to the Muslims down to the 12th century."^[93]

Oliver Joseph Lodge wrote in the Pioneers of Science:

"The only effective link between the old and the new science is afforded by the Arabs. The dark ages come as an utter gap in the scientific history of Europe, and for more than a thousand years there was not a scientific man of note except in Arabia."^[94]

Muhammad Iqbal wrote in The Reconstruction of Religious Thought in Islam:

"Thus the experimental method, reason and observation introduced by the Arabs were responsible for the rapid advancement of science during the medieval times."^{[22][page needed]}

Peer review

The first documented description of a peer review process is found in the Ethics of the Physician written by Ishaq bin Ali al-Rahwi (854–931) of al-Raha, Syria, who describes the first medical peer review process. His work, as well as later Arabic medical manuals, states that a visiting physician must always make duplicate notes of a patient's condition on every visit. When the patient was cured or had died, the notes of the physician were examined by a local medical council of other physicians, who would review the practising physician's notes to decide whether his or her performance met the required standards of medical care. If their reviews were negative, the practicing physician could face a lawsuit from a maltreated patient.^[95]

Applied sciences

Fielding H. Garrison wrote in the History of Medicine:

"The Saracens themselves were the originators not only of algebra, chemistry, and geology, but of many of the so-called improvements or refinements of civilization, such as street lamps, window-panes, firework, stringed instruments, cultivated fruits, perfumes, spices, etc..."^[21]

In the applied sciences, a significant number of inventions and technologies were produced by medieval Muslim scientists and engineers such as Abbas Ibn Firnas, Taqi al-Din, and particularly al-Jazari, who is considered a pioneer in modern engineering.^[96] Some of the inventions believed to have come from the medieval Islamic world include the programmable automaton,^[97] coffee, the soap bar, shampoo, liquefaction, crystallisation, purification, oxidisation, evaporation, filtration, distilled alcohol, uric acid, nitric acid, alembic, the crankshaft, the valve, quilting, the scalpel, surgical catgut, the windmill, inoculation, the fountain pen, cryptanalysis, frequency analysis, the three-course meal, stained glass and quartz glass, Persian carpet, explosive rockets and incendiary devices^[98]

Agricultural sciences

During the Arab Agricultural Revolution, Muslim scientists made significant advances in botany and laid the foundations of agricultural science. Muslim botanists and agriculturists demonstrated advanced agronomical, agrotechnical and economic knowledge in areas such as meteorology, climatology, hydrology, and soil occupation. They also demonstrated agricultural knowledge in areas such as pedology, agricultural ecology, irrigation, preparation of soil, planting, spreading of manure, sowing, cutting trees, grafting, pruning, prophylaxis, phytotherapy, the care and improvement of cultures and plants, and the harvest and storage of crops.^[99]

Al-Dinawari (828-896) is considered the founder of Arabic botany for his Book of Plants, in which he described at least 637 plants and discussed plant evolution from its birth to its death, describing the phases of plant growth and the production of flowers and fruit.^[100]

In the 13th century, the Andalusian-Arabian biologist Abu al-Abbas al-Nabati developed an early scientific method for botany, introducing empirical and experimental techniques in the testing, description and identification of numerous materia medica, and separating unverified reports from those supported by actual tests and observations.^[101] His student Ibn al-Baitar published the Kitab al-Jami fi al-Adwiya al-Mufrada, which is considered one of the greatest botanical compilations in history, and was a botanical authority for centuries. It contains details on at least 1,400 different plants, foods, and drugs, 300 of which were original discoveries. His work was also influential in Europe after it was translated into Latin in 1758.^[75][102]

Medicine

Muslim physicians made many significant advances and contributions to medicine, including anatomy, ophthalmology, pathology, the pharmaceutical sciences (including pharmacy and pharmacology), physiology, and surgery. Muslim physicians set up dedicated hospitals, which later spread to Europe during the Crusades, inspired by the hospitals in the Middle East.^[103]

Al-Kindi wrote De Gradibus, in which he first demonstrated the application of quantification and mathematics to medicine, particularly in the field of pharmacology. This includes the development of a mathematical scale to quantify the strength of drugs, and a system that would allow a doctor to determine in advance the most critical days of a patient's illness.^[104] Razi (Rhazes) (865-925), a pioneer of pediatrics,^[105] recorded clinical cases of his own experience and provided very useful recordings of various diseases. His Comprehensive Book of Medicine, which introduced measles and smallpox, was very influential in Europe. He also introduced urinalysis and stool tests.^[106]

Abu al-Qasim (Abulcasis), considered a pioneer of modern surgery,^[107] wrote the Al-Tasrif (1000), a 30-volume medical encyclopedia which was taught at Muslim and European medical schools until the 17th century. He invented numerous surgical instruments, including the first instruments unique to women,^[108] as well as the surgical uses of catgut and forceps, the ligature, surgical needle, scalpel, curette, retractor, surgical spoon, sound, surgical hook, surgical rod, and specula,^{[citation needed]} bone saw,^{[98][dubious – discuss]} and plaster.^[109] In 1021, Ibn al-Haytham (Alhacen) made important advances in eye surgery, as he studied and correctly explained the process of sight and visual perception for the first time in his Book of Optics (1021).^[108]

Avicenna, who was a pioneer of experimental medicine and was also an influential thinker and medical scholar,^[103] wrote The Canon of Medicine (1025) and The Book of Healing (1027), which remained standard textbooks in both Muslim and European universities until at least the 17th century. Avicenna's contributions include the discovery of the contagious nature of infectious diseases, the introduction of quarantine to limit the spread of contagious diseases, the introduction of experimental medicine,^[110] evidence-based medicine, clinical trials,^[111] randomized controlled trials,^[112][113] efficacy tests,^[114][115] and clinical pharmacology,^[116] the importance of dietetics and the influence of climate and environment on health,^[117] the distinction of mediastinitis from pleurisy, the contagious nature of phthisis and tuberculosis, the distribution of diseases by water and soil, and the first careful descriptions of skin troubles, sexually transmitted diseases, perversions, and nervous ailments,^[103] as well the use of ice to treat fevers, and the separation of medicine from pharmacology, which was important to the development of the pharmaceutical sciences.^[108]

Ibn Zuhr (Avenzoar) is considered a pioneer of experimental surgery,^[118] for introducing the experimental method into surgery in the 12th century, as he was the first to employ animal testing in order to experiment with surgical procedures before applying them to human patients.^[84] He also performed the first dissections and postmortem autopsies on both humans as well as animals.^[119]

In 1242, Ibn al-Nafis, considered the Arab Father of Circulation,^[120] was the first to describe pulmonary circulation which form the basis of the circulatory system. His discovery, however, was based only on scientific speculation (and not experimentation, which would later be conducted by William Harvey), since medieval Islamic law forbade dissection (considered "mutilation") of the human body.^[121] He developed new systems of physiology and psychology to replace the Avicennian and Galenic systems, while discrediting many of their erroneous theories on the four humours, pulsation,^[122] bones, muscles, intestines, sensory organs, bilious canals, esophagus, stomach, etc.^[123] Ibn al-Lubudi (1210–1267) rejected the theory of four humours supported by Galen and Hippocrates, discovered that the body and its preservation depend exclusively upon blood, rejected Galen's idea that women can produce sperm, stated that the movement of arteries is becaues of the movement of the heart, that the heart is the first organ to form in a fetus' body (rather than the brain as claimed by Hippocrates), and that the bones forming the brain can grow into tumors.^[124]

The Tashrih al-badan (Anatomy of the body) of Mansur ibn Ilyas (c. 1390) contained comprehensive diagrams of the body's structural, nervous and circulatory systems.^[125] During the Black Death bubonic plague in 14th century al-Andalus, Ibn Khatima and Ibn al-Khatib hypothesized that infectious diseases are caused by "contagious entities" which enter the human body.^[126] Other medical innovations first introduced by Muslim physicians include the discovery of the immune system, the use of animal testing, and the combination of medicine with other sciences (including agriculture, botany, chemistry, and pharmacology),^[108] as well as the invention of the injection syringe by Ammar ibn Ali al-Mawsili in 9th century Iraq, the first drugstores in Baghdad (754), the distinction between medicine and pharmacy by the 12th century, and the discovery of at least 2,000 medicinal and chemical substances.^[127]

Formal sciences

Logic

Islamic logic not only included the study of formal patterns of inference and their validity but also elements of the philosophy of language and elements of epistemology and metaphysics. Due to disputes with Arabic grammarians, Islamic philosophers were very interested in working out the relationship between logic and language, and they devoted much discussion to the question of the subject matter and aims of logic in relation to reasoning and speech. In the area of formal logical analysis, they elaborated upon the theory of terms, propositions and syllogisms. They considered the syllogism to be the form to which all rational argumentation could be reduced, and they regarded syllogistic theory as the focal point of logic. Even poetics was considered as a syllogistic art in some fashion by many major Islamic logicians.

Important developments made by Muslim logicians included the development of "Avicennian logic" as a replacement of Aristotelian logic. Avicenna's system of logic was responsible for the introduction of hypothetical syllogism,^[128] temporal modal logic,^[129][130] and inductive logic.^[131][132] Other important developments in Islamic philosophy include the development of a strict science of citation, the isnad or "backing", and the development of a scientific method of open inquiry to disprove claims, the ijtihad, which could be generally applied to many types of questions. From the 12th century, despite the logical sophistication of al-Ghazali, the rise of the Asharite school in the late Middle Ages slowly limited original work on logic in the Islamic world, though it did continue into the 15th century.

Mathematics

John J. O'Connor and Edmund F. Robertson wrote in the MacTutor History of Mathematics archive:

"Recent research paints a new picture of the debt that we owe to Islamic mathematics. Certainly many of the ideas which were previously thought to have been brilliant new conceptions due to European mathematicians of the sixteenth, seventeenth and eighteenth centuries are now known to have been developed by Persian/Islamic mathematicians around four centuries earlier."^[133]

Al-Khwarizmi (780-850) (born in Iran) , from whose name the word algorithm derives, contributed significantly to algebra, which is named after his book, Kitab al-Jabr, the first book on elementary algebra.^[134] He also introduced what is now known as Arabic numerals, which originally came from India, though Muslim mathematicians did make several refinements to the number system, such as the introduction of decimal point notation. Al-Kindi (801-873) was a pioneer in cryptanalysis and cryptology. He gave the first known recorded explanations of cryptanalysis and frequency analysis in A Manuscript on Deciphering Cryptographic Messages.^[135]

The first known proof by mathematical induction appears in a book written by Al-Karaji around 1000 AD, who used it to prove the binomial theorem, Pascal's triangle, and the sum of integral cubes.^[136] The historian of mathematics, F. Woepcke,^[137] praised Al-Karaji for being "the first who introduced the theory of algebraic calculus." Ibn al-Haytham was the first mathematician to derive the formula for the sum of the fourth powers, and using the method of induction, he developed a method for determining the general formula for the sum of any integral powers, which was fundamental to the development of integral calculus.^[138] The 11th century poet-mathematician Omar Khayyám was the first to find general geometric solutions of cubic equations and laid the foundations for the development of analytic geometry, algebraic geometry and non-Euclidean geometry. Sharaf al-Din al-Tusi (1135–1213) found algebraic and numerical solutions to cubic equations and was the first to discover the derivative of cubic polynomials, an important result in differential calculus.^[139]

Other achievements of Muslim mathematicians include the invention of spherical trigonometry,^[140] the discovery of all the trigonometric functions besides sine and cosine, early inquiry which aided the development of analytic geometry by Ibn al-Haytham, the first refutations of Euclidean geometry and the parallel postulate by Nasīr al-Dīn al-Tūsī, the first attempt at a non-Euclidean geometry by Sadr al-Din, the development of symbolic algebra by Abū al-Hasan ibn Alī al-Qalasādī,^[141] and numerous other advances in algebra, arithmetic, calculus, cryptography, geometry, number theory and trigonometry.

Natural sciences

Astrology

Islamic astrology, in Arabic ilm al-nujum is the study of the heavens by early Muslims. In early Arabic sources, ilm al-nujum was used to refer to both astronomy and astrology. In medieval sources, however, a clear distinction was made between ilm al-nujum (science of the stars) or ilm al-falak (science of the celestial orbs), referring to astrology, and ilm al-haya (science of the figure of the heavens), referring to astronomy. Both fields were rooted in Greek, Persian, and Indian traditions. Despite consistent critiques of astrology by scientists and religious scholars, astrological prognostications required a fair amount of exact scientific knowledge and thus gave partial incentive for the study and development of astronomy.

The study of astrology was also refuted by several Muslim writers, including al-Farabi, Ibn al-Haytham, Avicenna, al-Biruni and Averroes. Their reasons for refuting astrology were both due to the methods used by astrologers being conjectural rather than empirical and also due to the views of astrologers conflicting with orthodox Islam.^[142]

Astronomy

In astronomy, the works of Egyptian/Greek astronomer Ptolemy, particularly the Almagest, and the Indian work of Brahmagupta, were significantly refined over the years by Muslim astronomers. The astronomical tables of Al-Khwarizmi and of Maslamah Ibn Ahmad al-Majriti served as important sources of information for Latin European thinkers rediscovering the works of astronomy, where extensive interest in astrology was discouraged.

An important contribution by Islamic astronomers was their much greater emphasis on observational science and observational astronomy. Their work was based largely on actual observations of the heavens, far more so than the earlier Greek tradition which relied heavily upon abstract calculation.^[143] This led to the emergence of the first astronomical observatories, in the sense of modern scientific research institutes, in the Muslim world by the early 9th century.^{[144][145][146]} Accurate Zij catalogues were at the Islamic observatories, which were the first specialized astronomical institutions with their own scientific staff,^[144] director, astronomical program,^[145] large astronomical instruments, and building where astronomical research and observations are carried out. These Islamic observatories were also the first to employ enormously large astronomical instruments in order to greatly improve the accuracy of observations.^[144]

In the 10th century, Abd al-Rahman al-Sufi (Azophi) carried out observations on the stars and described their positions, magnitudes, brightness, and colour, and drawings for each constellation in his Book of Fixed Stars. He also gave the first descriptions and pictures of "A Little Cloud" now known as the Andromeda Galaxy. He mentions it as lying before the mouth of a Big Fish, an Arabic constellation. This "cloud" was apparently commonly known to the Isfahan astronomers, very probably before 905 AD.^[147] The first recorded mention of the Large Magellanic Cloud was also given by al-Sufi.^[148][149]

In the 11th century, Muslim astronomers began questioning the Ptolemaic system, beginning with Ibn al-Haytham, and they were the first to conduct elaborate experiments related to astronomical phenomena, beginning with the introduction of the experimental method into astronomy by Abu Rayhan Biruni and Ibn al-Haytham.^[150] Many of them made changes and corrections to the Ptolemaic model and proposed alternative non-Ptolemaic models within a geocentric framework. In particular, the corrections and critiques of al-Battani, Ibn al-Haytham, and Averroes, and the non-Ptolemaic models of the Maragha astronomers, Nasir al-Din al-Tusi (Tusi-couple), Mo'ayyeduddin Urdi (Urdi lemma), and Ibn al-Shatir, were later adapted into the heliocentric Copernican model,^{[151][152][unreliable source?]} and that Copernicus' arguments for the Earth's rotation were similar to those of al-Tusi and Ali Qushji.^[153] Some have referred to the achievements of the Maragha school as a "Maragha Revolution", "Maragha School Revolution", or "Scientific Revolution before the Renaissance".^[12]

Other contributions from Muslim astronomers include Biruni speculating that the Milky Way galaxy is a collection of numerous nebulous stars, the development of a planetary model without any epicycles by Ibn Bajjah (Avempace),^[154] the development of universal astrolabes,^[155] the invention of numerous other astronomical instruments, continuation of inquiry into the motion of the planets, Ja'far Muhammad ibn Mūsā ibn Shākir's discovery that the heavenly bodies and celestial spheres are subject to the same physical laws as Earth,^[156] the first elaborate experiments related to astronomical phenomena, the use of exacting empirical observations and experimental techniques,^[157] the discovery that the celestial spheres are not solid and that the heavens are less dense than the air by Ibn al-Haytham,^[158] the separation of natural philosophy from astronomy by Ibn al-Haytham^[159] and Qushji,^[153] the rejection of the Ptolemaic model on empirical rather than philosophical grounds by Ibn al-Shatir,^[12] and the first empirical observational evidence of the Earth's rotation by al-Tusi and al-Qushji.^[153] Several Muslim astronomers also discussed the possibility of a heliocentric model with elliptical orbits,^[160] such as Ja'far ibn Muhammad Abu Ma'shar al-Balkhi, Ibn al-Haytham, Abū al-Rayhān al-Bīrūnī, al-Sijzi, Najm al-Dīn al-Qazwīnī al-Kātibī, and Qutb al-Din al-Shirazi.^[161]

In the 12th century, Fakhr al-Din al-Razi criticized the idea of the Earth's centrality within the universe, and instead argued that there are more than "a thousand thousand worlds (alfa alfi 'awalim) beyond this world such that each one of those worlds be bigger and more massive than this world as well as having the like of what this world has."^[162] The first empirical observational evidence of the Earth's rotation was given by Nasīr al-Dīn al-Tūsī in the 13th century and by Ali Qushji in the 15th century, followed by Al-Birjandi who developed an early hypothesis on "circular inertia" by the early 16th century.^[153] Natural philosophy (particularly Aristotelian physics) was separated from astronomy by Ibn al-Haytham (Alhazen) in the 11th century, by Ibn al-Shatir in the 14th century,^[159] and Qushji in the 15th century, leading to the development of an independent astronomical physics.^[153]

Chemistry

The 9th century chemist, Jābir ibn Hayyān (Geber), is considered a pioneer of chemistry,^{[98][163][164]} for introducing an early experimental method for chemistry, as well as the alembic, still, retort, pure distillation, liquefaction, crystallisation, purification, oxidisation, evaporation, and filtration.^[98]

Al-Kindi was the first to refute the study of traditional alchemy and the theory of the transmutation of metals,^[165] followed by Abū Rayhān al-Bīrūnī,^[166] Avicenna,^[167] and Ibn Khaldun. Avicenna also invented steam distillation and produced the first essential oils, which led to the development of aromatherapy. Razi first distilled petroleum, invented kerosene and kerosene lamps, soap bars and modern recipes for soap, and antiseptics. In his Doubts about Galen, al-Razi was also the first to prove both Aristotle's theory of classical elements and Galen's theory of humorism wrong using an experimental method.^{[citation needed]} In the 13th century, Nasīr al-Dīn al-Tūsī stated a version of the law of conservation of mass, noting that a body of matter is able to change, but is not able to disappear.^[168]

Will Durant wrote in The Story of Civilization IV: The Age of Faith:

"Chemistry as a science was almost created by the Moslems; for in this field, where the Greeks (so far as we know) were confined to industrial experience and vague hypothesis, the Saracens introduced precise observation, controlled experiment, and careful records. They invented and named the alembic (al-anbiq), chemically analyzed innumerable substances, composed lapidaries, distinguished alkalis and acids, investigated their affinities, studied and manufactured hundreds of drugs. Alchemy, which the Moslems inherited from Egypt, contributed to chemistry by a thousand incidental discoveries, and by its method, which was the most scientific of all medieval operations."^[20]

George Sarton wrote in the Introduction to the History of Science:

"We find in his (Jabir, Geber) writings remarkably sound views on methods of chemical research, a theory on the geologic formation of metals (the six metals differ essentially because of different proportions of sulphur and mercury in them); preparation of various substances (e.g., basic lead carbonatic, arsenic and antimony from their sulphides)."

Earth sciences

Muslim scientists made a number of contributions to the Earth sciences. Alkindus was the first to introduce experimentation into the Earth sciences.^[82] Biruni is considered a pioneer of geodesy for his important contributions to the field,^[169][170] along with his significant contributions to geography and geology.

Among his writings on geology, Biruni wrote the following on the geology of India:

"But if you see the soil of India with your own eyes and meditate on its nature, if you consider the rounded stones found in earth however deeply you dig, stones that are huge near the mountains and where the rivers have a violent current: stones that are of smaller size at a greater distance from the mountains and where the streams flow more slowly: stones that appear pulverised in the shape of sand where the streams begin to stagnate near their mouths and near the sea - if you consider all this you can scarcely help thinking that India was once a sea, which by degrees has been filled up by the alluvium of the streams."^[171]

John J. O'Connor and Edmund F. Robertson write in the MacTutor History of Mathematics archive:

"Important contributions to geodesy and geography were also made by al-Biruni. He introduced techniques to measure the earth and distances on it using triangulation. He found the radius of the earth to be 6339.6 km, a value not obtained in the West until the 16th century. His Masudic canon contains a table giving the coordinates of six hundred places, almost all of which he had direct knowledge."^[83]

George Sarton wrote in the Introduction to the History of Science:

"We find in his (Jabir, Geber) writings remarkably sound views on methods of chemical research, a theory on the geologic formation of metals (the six metals differ essentially because of different proportions of sulphur and mercury in them)..."^{[page needed]}

In geology, Avicenna hypothesized on two causes of mountains in The Book of Healing (1027) and developed the law of superposition and concept of uniformitarianism.^[172][173] In cartography, the Piri Reis map drawn by the Ottoman cartographer Piri Reis in 1513, was one of the earliest world maps to include the Americas, and perhaps the first to include Antarctica. His map of the world was considered the most accurate in the 16th century.

The earliest known treatises dealing with environmentalism and environmental science, especially pollution, were Arabic treatises written by al-Kindi, al-Razi, Ibn Al-Jazzar, al-Tamimi, al-Masihi, Avicenna, Ali ibn Ridwan, Abd-el-latif, and Ibn al-Nafis. Their works covered a number of subjects related to pollution such as air pollution, water pollution, soil contamination, municipal solid waste mishandling, and environmental impact assessments of certain localities.^[174] Cordoba, al-Andalus also had the first waste containers and waste disposal facilities for litter collection.^[175]

Physics

In the optics field of physics, Ibn Sahl (c. 940-1000), a mathematician and physicist connected with the court of Baghdad, wrote a treatise On Burning Mirrors and Lenses in 984 in which he set out his understanding of how curved mirrors and lenses bend and focus light. Ibn Sahl is now credited with first discovering the law of refraction, usually called Snell's law.^[176][177] He used this law to work out the shapes of lenses that focus light with no geometric aberrations, known as anaclastic lenses.

Ibn al-Haytham (Alhazen) (965-1039), who is considered a pioneer of optics and the scientific method, developed a broad theory of light and optics in his Book of Optics which explained vision, using geometry and anatomy, and stated that each point on an illuminated area or object radiates light rays in every direction, but that only one ray from each point, which strikes the eye perpendicularly, can be seen. The other rays strike at different angles and are not seen. He used the example of the camera obscura and pinhole camera, which produces an inverted image, to support his argument. This contradicted Ptolemy's theory of vision that objects are seen by rays of light emanating from the eyes. Alhacen held light rays to be streams of minute particles that travelled at a finite speed. He improved accurately described the refraction of light, and discovered the laws of refraction. He dealt at length with the theory of various physical phenomena like shadows, eclipses, and the rainbow. He also attempted to explain binocular vision and the moon illusion. Through these extensive researches on optics, he is considered a pioneer of modern optics. His Book of Optics was later translated into Latin, and has been ranked as one of the most influential books in the history of physics,^[178] for initiating a revolution in optics^[26] and visual perception.^[27]

Avicenna (980-1037) agreed that the speed of light is finite, as he "observed that if the perception of light is due to the emission of some sort of particles by a luminous source, the speed of light must be finite."^[179] Abū Rayhān al-Bīrūnī (973-1048) also agreed that light has a finite speed, and he was the first to discover that the speed of light is much faster than the speed of sound.^[83] Qutb al-Din al-Shirazi (1236–1311) and Kamāl al-Dīn al-Fārisī (1260–1320) gave the first correct explanations for the rainbow phenomenon.^[180]

In mechanics, Ja'far Muhammad ibn Mūsā ibn Shākir (800-873) of the Banū Mūsā hypothesized that heavenly bodies and celestial spheres were subject to the same laws of physics as Earth.^[156] Abū Rayhān al-Bīrūnī (973-1048), and later al-Khazini, developed experimental scientific methods for mechanics, especially the fields of statics and dynamics, particularly for determining specific weights, such as those based on the theory of balances and weighing. Muslim physicists were influential in the process of combined the fields of hydrostatics with dynamics to give birth to hydrodynamics. They applied the mathematical theories of ratios and infinitesimal techniques, and introduced algebraic and fine calculation techniques into the field of statics. They also generalized the concept of the centre of gravity and applied it to three-dimensional bodies and founded the theory of the ponderable lever.^[181] Al-Biruni also theorized that acceleration is connected with non-uniform motion.^[83]

In mechanics, Ibn al-Haytham discussed the theory of attraction between masses, and he stated that the heavenly bodies "were accountable to the laws of physics".^[182] Ibn al-Haytham also enunciated the law of inertia when he stated that a body moves perpetually unless an external force stops it or changes its direction of motion.^[88] He also developed the concept of momentum,^[183] though he did not quantify this concept mathematically. Avicenna (980-1037) developed the concept of momentum, when attempting to provide a quantitive relation between the weight and velocity of a moving body.^[184] His theory of motion also resembled the concept of inertia in classical mechanics.^[185]

In 1121, al-Khazini, in The Book of the Balance of Wisdom, proposed that the gravity and gravitational potential energy of a body varies depending on its distance from the centre of the Earth.^[186] Avempace (d. 1138) argued that there is always a reaction force for every force exerted,^[187] though he did not refer to the reaction force as being equal to the exerted force.^[188] His theory of motion had an important influence on later physicists like Galileo Galilei.^[189] Hibat Allah Abu'l-Barakat al-Baghdaadi (1080–1165) wrote a critique of Aristotelian physics entitled al-Mu'tabar, where he negated Aristotle's idea that a constant force produces uniform motion, as he theorized that a force applied continuously produces acceleration.^[190] He also described acceleration as the rate of change of velocity.^[191] Averroes (1126–1198) defined and measured force as "the rate at which work is done in changing the kinetic condition of a material body"^[192] and correctly argued "that the effect and measure of force is change in the kinetic condition of a materially resistant mass."^[193] In the early 16th century, al-Birjandi developed a hypothesis similar to "circular inertia."^[153] Contributions to statistics by Arabs played an indispensible role in the later development of classical mechanics in early modern Europe.^[194]

Zoology

Al-Jahiz (781-869) described an early theory of natural selection and struggle for existence,^[195] and according to Mehmet Bayrakdar his theory on biological evolution is very similar to Darwin's.^[196] Al-Jahiz was also the first to discuss food chains,^[197] and was also an early adherent of environmental determinism, arguing that the environment can determine the physical characteristics of the inhabitants of a certain community and that the origins of different human skin colors is the result of the environment.^[198]

Ibn al-Haytham wrote a book in which he argued for evolutionism (although not natural selection), and numerous other Islamic scholars and scientists, such as Ibn Miskawayh, the Brethren of Purity, al-Khazini, Abū Rayhān al-Bīrūnī, Nasir al-Din Tusi, and Ibn Khaldun, discussed and developed these ideas. Translated into Latin, these works began to appear in the West after the Renaissance and appear to have had an impact on Western science.

Ibn Miskawayh's al-Fawz al-Asghar and the Brethren of Purity's Encyclopedia of the Brethren of Purity (The Epistles of Ikhwan al-Safa) expressed evolutionary ideas on how species evolved from matter, into vapor, and then water, then minerals, then plants, then animals, then apes, and then humans. These works were known in Europe and likely had an influence on Darwinism.^{[199][dubious – discuss]}

Social sciences

Sociology and Anthropology

Significant contributions were made to the social sciences in the Islamic civilization. Abū al-Rayhān al-Bīrūnī (973-1048) has been described as "the first anthropologist".^[169] He wrote detailed comparative studies on the anthropology of peoples, religions and cultures in the Middle East, Mediterranean and South Asia. Biruni's anthropology of religion was only possible for a scholar deeply immersed in the lore of other nations.^[200] Biruni has also been praised by several scholars for his Islamic anthropology.^[201] Biruni is also considered a pioneer of Indology.^[109] Al-Saghani (died 990) wrote some of the earliest comments on the history of science, which included a comparison between the more theoretical approach of the "ancients" (including the ancient Egyptians, Babylonians, Greeks and Indians) to that of the more experimental approach of the "modern scholars" (the Muslim scientists of his time).^[202] Al-Muqaddasi (b. 945) also made contributions to the social sciences.

Ibn Khaldun (1332–1406) is considered a forerunner of several social sciences^[203] such as demography,^[170] cultural history,^[204] historiography,^[205] the philosophy of history,^[206] sociology,^[170][206] and economics.^[207][208] He is best known for his Muqaddimah (Latinized as Prolegomenon). Some of the ideas he introduced in the Muqaddimah include social philosophy, social conflict theories, social cohesion, social capital, social networks, dialectics, the Laffer curve, the historical method, systemic bias, the rise and fall of civilizations, feedback loops, systems theory, and corporate social responsibility. He also introduced the scientific method into the social sciences.^[2]

Franz Rosenthal wrote in the History of Muslim Historiography:

"Muslim historiography has at all times been united by the closest ties with the general development of scholarship in Islam, and the position of historical knowledge in MusIim education has exercised a decisive influence upon the intellectual level of historicai writing....The Muslims achieved a definite advance beyond previous historical writing in the sociological understanding of history and the systematisation of historiography. The development of modern historical writing seems to have gained considerably in speed and substance through the utilization of a Muslim Literature which enabled western historians, from the seventeenth century on, to see a large section of the world through foreign eyes. The Muslim historiography helped indirectly and modestly to shape present day historical thinking."^[209]

Psychology

"Islamic psychology"^[210] or Ilm-al Nafsiat^[211] refers to the study of the Nafs ("self" or "psyche")^[212] in the Islamic world and encompassed a "broad range of topics including the qalb (heart), the ruh (spirit), the aql (intellect) and irada (will)."^[211] Al-Kindi (Alkindus) was the first to experiment with music therapy,^[213] and Ali ibn Sahl Rabban al-Tabari was the first to practice 'al-‘ilaj al-nafs ("psychotherapy").^[214] The concepts of al-tibb al-ruhani ("spiritual health") and "mental hygiene" were introduced by Ahmed ibn Sahl al-Balkhi,^[212] who was "probably the first cognitive and medical psychologist to clearly differentiate between neuroses and psychoses, to classify neurotic disorders, and to show in detail how rational and spiritual cognitive therapies can be used to treat each one of his classified disorders."^[214] Al-Razi (Rhazes) made significant advances in psychiatry in his landmark texts El-Mansuri and Al-Hawi, which presented definitions, symptoms and treatments for mental illnesses and problems related to mental health. He also ran the psychiatric ward of a Baghdad hospital. Such institutions could not exist in Europe at the time because of fear of demonic possessions.^[215]

Al-Farabi wrote the first treatises on social psychology and dealt with consciousness studies.^[214] In al-Andalus, Abulcasis pioneered neurosurgery, while Ibn Zuhr (Avenzoar) gave the first accurate descriptions on neurological disorders and contributed to modern neuropharmacology, and Averroes suggested the existence of Parkinson's disease.^[216] Ali ibn Abbas al-Majusi discussed "the relationship between certain psychological events to the physiological changes in the body",^[212] while Avicenna anticipated the word association test,^[215] discussed neuropsychiatry in The Canon of Medicine,^[217] and described the first thought experiments on self-awareness and self-consciousness.^[218]

Some have argued that Ibn al-Haytham (Alhazen) should be considered "the founder of experimental psychology",^{[219][220][221]} for his experimental work on the psychology of visual perception in the Book of Optics.^[222] He was the first scientist to argue that vision occurs in the brain, rather than the eyes and pointed out that personal experience has an effect on what people see and how they see, and that vision and perception are subjective.^[222] His investigations and experiments on psychology and visual perception included sensation, variations in sensitivity, sensation of touch, perception of colours, perception of darkness, an early attempt to explain the moon illusion, and binocular vision.^[219] Biruni was also a pioneer of experimental psychology, as he was the first to empirically describe the concept of reaction time.^[223] Al-Kindi's attempts to quantify perception are considered an anticipation of Weber's law.^[224]

Historiography of Islamic science

The history of science in the Islamic world, like all history, is filled with questions of interpretation. Historians of science generally consider that the study of Islamic science, like all history, must be seen within the particular circumstances of time and place. A. I. Sabra opened a recent overview of Arabic science by noting, "I trust no one would wish to contest the proposition that all of history is local history ... and the history of science is no exception."^[225]

Some scholars avoid such local historical approaches and seek to identify essential relations between Islam and science that apply at all times and places. The Pakistani physicist, Pervez Hoodbhoy, portrayed "religious fanaticism to be the dominant relation of religion and science in Islam". Sociologist Toby Huff claimed that Islam lacked the "rationalist view of man and nature" that became dominant in Europe. The Persian philosopher and historian of science, Seyyed Hossein Nasr saw a more positive connection in "an Islamic science that was spiritual and antisecular" which "point[ed] the way to a new 'Islamic science' that would avoid the dehumanizing and despiritualizing mistakes of Western science."^[226][227]

Nasr identified a distinctly Muslim approach to science, flowing from Islamic monotheism and the related theological prohibition against portraying graven images. In science, this is reflected in a philosophical disinterest in describing individual material objects, their properties and characteristics and instead a concern with the ideal, the Platonic form, which exists in matter as an expression of the will of the Creator. Thus one can "see why mathematics was to make such a strong appeal to the Muslim: its abstract nature furnished the bridge that Muslims were seeking between multiplicity and unity."^[228]

Some historians of science, however, question the value of drawing boundaries that label the sciences, and the scientists who practice them, in specific cultural, civilizational, or linguistic terms. Consider the case of Nasir al-Din Tusi (1201–1274), who invented his mathematical theorem, the Tusi Couple, while he was director of Maragheh observatory. Tusi's patron and founder of the observatory was the non-Muslim Mongol conqueror of Baghdad, Hulagu Khan. The Tusi-couple "was first encountered in an Arabic text, written by a man who spoke Persian at home, and used that theorem, like many other astronomers who followed him and were all working in the "Arabic/Islamic" world, in order to reform classical Greek astronomy, and then have his theorem in turn be translated into Byzantine Greek towards the beginning of the 14th century, only to be used later by Copernicus and others in Latin texts of Renaissance Europe."^[229]