• Physician, Surgeon and Philosopher Claudius Galenus (Κλαύδιος Γαληνός), 129
• Physician, Chemist and Philosopher Muhammad ibn Zakariya al-Razi (Rhazes), 865

The son of Aelius Nicon, a wealthy architect with scholarly interests, Galen received a comprehensive education that prepared him for a successful career as a physician and philosopher. He traveled extensively, exposing himself to a wide variety of medical theories and discoveries before settling in Rome, where he served prominent members of Roman society and eventually was given the position of personal physician to several emperors.

Galen's understanding of anatomy and medicine was principally influenced by the then current theory of humorism, as advanced by many ancient Greek physicians such as Hippocrates. His theories dominated and influenced Western medical science for nearly two millennia. His anatomical reports, based mainly on dissection of monkeys and pigs, remained uncontested until 1543, when printed descriptions and illustrations of human dissections were published in the seminal work De humani corporis fabrica by Andreas Vesalius where Galen's physiological theory was accommodated to these new observations. Galen's theory of the physiology of the circulatory system endured until 1628, when William Harvey published his treatise entitled De motu cordis, in which he established that blood circulates, with the heart acting as a pump. Medical students continued to study Galen's writings until well into the 19th century. Galen conducted many nerve ligation experiments that supported the theory, which is still accepted today, that the brain controls all the motions of the muscles by means of the cranial and peripheral nervous systems.

Galen saw himself as both a physician and a philosopher, as he wrote in his treatise entitled That the Best Physician is also a Philosopher. Galen was very interested in the debate between the rationalist and empiricist medical sects, and his use of direct observation, dissection and vivisection represents a complex middle ground between the extremes of those two viewpoints. Many of his works have been preserved and/or translated from the original Greek, although many were destroyed and some credited to him are believed to be spurious. Although there is some debate over the date of his death, he was no younger than seventy when he died.

Galen's name Greek: Γαληνός, Galēnos comes from the adjective "γαληνός", "calm".

Galen describes his early life in On the affections of the mind. He was born in September 129 AD; his father, Aelius Nicon, was a wealthy patrician, an architect and builder, with eclectic interests including philosophy, mathematics, logic, astronomy, agriculture and literature. Galen describes his father as a "highly amiable, just, good and benevolent man". At that time Pergamon was a major cultural and intellectual center, noted for its library (Eumenes II), second only to that in Alexandria, and attracted both Stoic and Platonic philosophers, to whom Galen was exposed at age 14. His studies also took in each of the principal philosophical systems of the time, including Aristotelian and Epicurean. His father had planned a traditional career for Galen in philosophy or politics and took care to expose him to literary and philosophical influences. However, Galen states that in around 145 AD his father had a dream in which the god Asclepius (Aesculapius) appeared and commanded Nicon to send his son to study medicine. Again, no expense was spared, and following his earlier liberal education, at 16 he began studies at the prestigious local sanctuary or Asclepieum dedicated to Asclepius, god of medicine, as a θεραπευτής (therapeutes, or attendant) for four years. There he came under the influence of men like Aeschrion of Pergamon, Stratonicus and Satyrus. Asclepiea functioned as spas or sanitoria to which the sick would come to seek the ministrations of the priesthood. The temple at Pergamon was eagerly sought by Romans in search of a cure. It was also the haunt of notable people such as Claudius Charax the historian, Aelius Aristides the orator, Polemo the sophist, and Cuspius Rufinus the Consul.

In 148, when he was 19, his father died, leaving him independently wealthy. He then followed the advice he found in Hippocrates' teaching and traveled and studied widely including such destinations as Smyrna (now Izmir), Corinth, Crete, Cilicia (now Çukurova), Cyprus and finally the great medical school of Alexandria, exposing himself to the various schools of thought in medicine. In 157, aged 28, he returned to Pergamon as physician to the gladiators of the High Priest of Asia, one of the most influential and wealthiest men in Asia. Galen claims that the High Priest chose him over other physicians after he eviscerated an ape and challenged other physicians to repair the damage. When they refused, Galen performed the surgery himself and in so doing won the favor of the High Priest of Asia. Over his four years there he learned the importance of diet, fitness, hygiene and preventive measures, as well as living anatomy, and the treatment of fractures and severe trauma, referring to their wounds as "windows into the body". Only five deaths occurred while he held the post, compared to sixty in his predecessor's time, a result which is generally ascribed to the attention he paid to their wounds. At the same time he pursued studies in theoretical medicine and philosophy.

Galen went to Rome in 162 AD and made his mark as a practicing physician. His impatience brought him into conflict with other doctors and he felt menaced by them. His demonstrations there antagonized the less able and original physicians in the city. They plotted against him and he feared he might be driven away or poisoned so he left the city.

Rome then engaged in the foreign wars in 161 AD. Marcus Aurelius and his colleague Lucius Verus were in the north fighting the Marcomanni. During the autumn of 169 AD when Roman troops were returning to Aquileia, the great plague broke out and the emperor summoned Galen back to Rome. He was ordered to accompany Marcus and Verus to Germany as the court physician. In the following spring Marcus was persuaded to release Galen after receiving a report that Asclepius was against the project. He was left behind to act as physician to the imperial heir Commodus. It was here in court that Galen wrote extensively on medical subjects. Ironically, Lucius Verus died in 169, and Marcus Aurelius himself died in 180, both victims of the plague.

Galen was the physician to Commodus for much of the emperor’s life and treated his common illnesses. According to Dio Cassius 72.14.3–4, in about 189 AD, under Commodus’ reign, a pestilence occurred, the largest of which he had knowledge, in which 2,000 people died in Rome each day. It is most likely that this was the same plague that struck Rome during Marcus Aurelius’ reign.

Galen became physician to Septimius Severus during his reign in Rome. Galen compliments Severus and Caracalla on keeping a supply of drugs for their friends and mentions three cases in which they had been of use in 198 AD.

The Antonine Plague was named after Marcus Aurelius’ family name of Antoninus. It was also known as the Plague of Galen and holds an important place in medicinal history because of its association with Galen. Galen had first hand knowledge of the disease. He was in Rome when it struck in 166 AD, and was also present in the winter of 168 – 69 during an outbreak among troops stationed at Aquileia. He had experience with the epidemic, referring to it as very long lasting, and describes its symptoms and his treatment of it. Unfortunately, his references to the plague are scattered and brief. Galen was not trying to present a description of the disease so that it could be recognized in future generations; he was more interested in the treatment and physical effects of the disease. For example, in his writings about a young man afflicted with the plague, he concentrated on the treatment of internal and external ulcerations. According to Niebuhr "this pestilence must have raged with incredible fury; it carried off innumerable victims. The ancient world never recovered from the blow inflected upon it by the plague which visited it in the reign of M. Aurelius." The mortality rate of the plague was 7–10 percent; the outbreak in 165 – 6 – 168 would have caused approximately 3.5 to 5 million deaths. Otto Seek believes that over half the population of the empire perished. J. F. Gilliam believes that the Antonine plague probably caused more deaths than any other epidemic during the empire before the mid 3rd century. It is believed that the Antonine Plague was smallpox, because though his description is incomplete, Galen gave enough information to enable a firm identification of the disease.

Galen notes that the exanthema covered the victim’s entire body and was usually black. The exanthem became rough and scabby where there was no ulceration. He states that those who were going to survive developed a black exanthem. According to Galen, it was black because of a remnant of blood putrefied in a fever blister that was pustular. His writings state that raised blisters were present in the Antonine plague, usually in the form of a blistery rash. Galen states that the skin rash was close to the one Thucydides described. Galen describes symptoms of the alimentary tract via a patient’s diarrhea and stools. If the stool was very black, the patient died. He says that the amount of black stools varied. It depended on the severity of the intestinal lesions. He observes that in cases where the stool was not black, the black exanthum appeared. Galen describes the symptoms of fever, vomiting, fetid breath, catarrh, cough and ulceration of the larynx and trachea.

When Peripatetic philosopher Eudemus became ill with Quartan fever, Galen felt obliged to treat him "since he was my teacher and I happened to live nearby." Galen wrote: "I return to the case of Eudemus. He was thoroughly attacked by the three attacks of quartan ague, and the doctors had given him up, as it was now mid winter." Some Roman physicians criticized Galen for his use of the prognosis in his treatment of Eudemus. This practice conflicted with the then current standard of care, which relied upon divination and mysticism. Galen retaliated against his detractors by defending his own methods. Garcia - Ballester quotes Galen as saying: "In order to diagnose, one must observe and reason. This was the basis of his criticism of the doctors who proceeded alogos and askeptos." However, Eudemus warned Galen that engaging in conflict with these physicians could lead to his assassination. "Eudemus said this, and more to the same effect; he added that if they were not able to harm me by unscrupulous conduct they would proceed to attempts at poisoning. Among other things he told me that, some ten years before, a young man had come to the city and had given, like me practical demonstrations of the resources of our art; this young man was put to death by poison, together with two servants who accompanied him."

Garcia - Ballester says the following of Galen’s use of prognosis: "In modern medicine, we are used to distinguishing between the diagnostic judgment (the scientific knowledge of what a patient has) and the prognostic judgment (the conjecture about what will happen to him.) Galen, like the Hippocratics, was not. For him, to understand a clinical case technically, ‘to diagnose’, was among other things, to know with greater or lesser certainty the outcome fore the patient, ‘to prognosticate’. Prognosis, then, is one of the essential problems and most important objectives of Galenic diagnosis. Galen was concerned to distinguish it from divination or prophecy, both to improve diagnosis technically and to enhance the physician’s reputation."

The 11th-century Suda lexicon states that Galen died at the age of 70, therefore about the year 199. However, there is a reference in Galen's treatise "On Theriac to Piso" (which may however be spurious) to events of 204. There are also statements in Arabic sources that he died at 87, after 17 years studying medicine and 70 practicing it, therefore about 217. Nutton believes that "On Theriac to Piso" is genuine, the Arabic sources are correct and that the Suda has erroneously interpreted the 70 years of Galen's career in the Arabic tradition as referring to his whole lifespan. Boudon - Millot more or less concurs and favors a date of 216.

Galen contributed a substantial amount to the Hippocratic understanding of pathology. Under Hippocrates’ bodily humors theory, differences in human moods come as a consequence of imbalances in one of the four bodily fluids: blood, yellow bile, black bile and phlegm. Galen promoted this theory and the typology of human temperaments. An imbalance of each humor corresponded with a particular human temperament (blood - sanguine, black bile - melancholic, yellow bile - choleric and phlegm - phlegmatic). Individuals with sanguine temperaments are extroverted and social. Choleric people have energy, passion and charisma. Melancholics are creative, kind and considerate. Phlegmatic temperaments are characterized by dependability, kindness and affection.

Galen’s principal interest was in human anatomy, but Roman law had prohibited the dissection of human cadavers since about 150 BC. Because of this restriction, Galen performed anatomical dissections on living (vivisection) and dead animals, mostly focusing on pigs and primates. This work turned out to be particularly useful because in most cases, the anatomical structures of these animals closely mirror those of humans. Galen clarified the anatomy of the trachea and was the first to demonstrate that the larynx generates the voice. Galen may have understood the importance of artificial ventilation, because in one of his experiments he used bellows to inflate the lungs of a dead animal.

Among Galen’s major contributions to medicine was his work on the circulatory system. He was the first to recognize that there were distinct differences between venous (dark) and arterial (bright) blood. Although his many anatomical experiments on animal models led him to a more complete understanding of the circulatory system, nervous system, respiratory system and other structures, his work was not without scientific inaccuracies. Galen believed that the circulatory system consisted of two separate one - way systems of distribution, rather than a single unified system of circulation. His understanding was that venous blood was generated in the liver, from where it was distributed and consumed by all organs of the body. He posited that arterial blood originated in the heart, from where it was distributed and consumed by all organs of the body. The blood was then regenerated in either the liver or the heart, completing the cycle. Galen also believed in the existence of a group of blood vessels he called the rete mirabile, near the back of the human brain. Both of these theories of the circulation of blood were later shown to be incorrect.

In his work De motu musculorum, Galen explained the difference between motor and sensory nerves, discussed the concept of muscle tone and explained the difference between agonists and antagonists.

Galen was also a highly skilled surgeon, and he performed surgical operations on human patients. Many of the procedures and techniques that he utilized would not be used again for centuries. Of particular note are procedures that Galen performed on patients’ brains and eyes. In order to correct cataracts in patients, Galen performed an operation that was similar to what is performed by contemporary ophthalmologists. Using a needle shaped instrument, Galen attempted to remove the cataract from behind the lens of the eye.

At first reluctantly, but then with increasing vigor, Galen promoted Hippocratic teaching, including venesection and bloodletting, then unknown in Rome. This was sharply criticized by the Erasistrateans, who predicted dire outcomes, believing that it was not blood but pneuma that flowed in the veins. Galen, however, staunchly defended venesection in his three books on the subject, and in his demonstrations and public disputations.

Although the main focus of his work was on medicine, anatomy and physiology, Galen also wrote about logic and philosophy. His writings were influenced by earlier Greek and Roman thinkers, including Plato, Aristotle and the Stoics. Galen was concerned to combine philosophical thought with medical practice, as in his brief work That the Best Physician is also a Philosopher. He took aspects from each group and combined them with his original thought. He regarded medicine as an interdisciplinary field that was best practiced by utilizing theory, observation and experimentation in conjunction.

Several schools of thought existed within the medical field during Galen's lifetime, the main two being the Empiricists and Rationalists (also called Dogmatists or Philosophers), with the Methodists being a smaller group. The Empiricists emphasized the importance of physical practice and experimentation, or "active learning" in the medical discipline. In direct opposition to the Empiricists were the Rationalists, who valued the study of established teachings in order to create new theories in the name of medical advancements. The Methodists formed somewhat of a middle ground, as they were not as experimental as the Empiricists, nor as theoretical as the Rationalists. The Methodists mainly utilized pure observation, showing greater interest in studying the natural course of ailments than making efforts to find remedies. Galen's education had exposed him to the four major schools of thought (Platonists, Peripatetics, Stoics, Epicureans), with teachers from the Rationalist sect and from the Empiricist sect.

Galen may have produced more work than any author in antiquity, rivaling the quantity of work issued from Augustine of Hippo. So profuse was Galen's output that the surviving texts represent nearly half of all the extant literature from ancient Greece. It has been reported that Galen employed twenty scribes to write down his words. Galen may have written as many as 600 treatises, amounting to some 10 million words. Although his surviving works amount to some 3 million words, this is thought to represent less than a third of his complete writings. In AD 191, a fire in the Temple of Peace destroyed many of his works, particularly treatises on philosophy.

Because Galen's works were not translated into Latin in the ancient period, and because of the collapse of the Roman Empire in the West, the study of Galen, along with the Greek medical tradition as a whole, went into decline in Western Europe during the Early Middle Ages, when very few Latin scholars could read Greek. However, Galen and the ancient Greek medical tradition generally continued to be studied and followed in the Eastern Roman Empire, commonly known as the Byzantine Empire. All of the extant Greek manuscripts of Galen were copied by Byzantine scholars. In the Abbasid period (after 750 AD) Arab Muslims began to be interested in Greek scientific and medical texts for the first time, and had some of Galen's texts translated into Arabic, often by Syrian Christian scholars. As a result some texts of Galen exist only in Arabic translation, while others exist only in medieval Latin translations of the Arabic. In some cases scholars have even attempted to translate from the Latin or Arabic back into Greek where the original is lost. For some of the ancient sources, such as Herophilus, Galen's account of their work is all that survives.

Even in his own time, forgeries and unscrupulous editions of his work were a problem, prompting him to write On his Own Books. Forgeries in Latin, Arabic or Greek continued until the Renaissance. Some of Galen's treatises have appeared under many different titles over the years. Sources are often in obscure and difficult to access journals or repositories. Although written in Greek, by convention the works are referred to by Latin titles, and often by merely abbreviations of those. No single authoritative collection of his work exists, and controversy remains as to the authenticity of a number of works attributed to Galen. Consequently research on Galen's work is fraught with hazard.

Various attempts have been made to classify Galen's vast output. For instance Coxe (1846) lists a Prolegomena, or introductory books, followed by 7 classes of treatise embracing Physiology (28 vols.), Hygiene (12), Aetiology (19), Semeiotics (14), Pharmacy (10), Blood letting (4) and Therapeutics (17), in addition to 4 of aphorisms, and spurious works. The most complete compendium of Galen's writings, surpassing even modern projects like the Corpus Medicorum Graecorum, is the one compiled and translated by Karl Gottlob Kühn of Leipzig between 1821 and 1833. This collection consists of 122 of Galen's treatises, translated from the original Greek into Latin (the text is presented in both languages). Over 20,000 pages in length, it is divided into 22 volumes, with 676 index pages. Many of Galen's works are included in the Thesaurus Linguae Graecae, a digital library of Greek literature started in 1972. Another useful modern source is the French Bibliothèque interuniversitaire de médicine (BIUM).

In his time, Galen's reputation as both physician and philosopher was legendary, the Emperor Marcus Aurelius describing him as "Primum sane medicorum esse, philosophorum autem solum" (first among doctors and unique among philosophers Praen 14: 660). Other contemporary authors in the Greek world confirm this including Theodotus the Shoemaker, Athenaeus and Alexander of Aphrodisias. The 7th century poet George of Pisida went so far as to refer to Christ as a second and neglected Galen. Galen continued to exert an important influence over the theory and practice of medicine until the mid 17th century in the Byzantine and Arabic worlds and Europe. Hippocrates and Galen form important landmarks of 600 years of Greek medicine. A. J. Brock describes them as representing the foundation and apex respectively. A few centuries after Galen Palladius Iatrosophista in his commentary on Hippocrates, stated that Hippocrates sowed and Galen reaped.

Thus Galen summarized and synthesized the work of his predecessors, and it is in Galen's words (Galenism) that Greek medicine was handed down to subsequent generations, such that Galenism became the means by which Greek medicine was known to the world. Frequently this was in the form of restating and reinterpreting, such as in Magnus of Nisibis' 4th century work on urine, which was in turn translated into Arabic. Yet the full importance of his contributions was not appreciated till long after his death. Galen's rhetoric and prolificity were so powerful as to convey the impression that there was little left to learn. The term Galenism has subsequently taken on both a positive and pejorative meaning as one that transformed medicine in late antiquity yet so dominated subsequent thinking as to stifle further progress.

After the collapse of the Western Empire the study of Galen and other Greek works almost disappeared in the Latin West. In contrast, in the predominantly Greek speaking eastern half of the Roman empire (Byzantium), many commentators of the subsequent centuries, such as Oribasius, physician to the emperor Julian who compiled a Synopsis in the 4th century, preserved and disseminated Galen's works, making Galenism more accessible. Nutton refers to these authors as the "medical refrigerators of antiquity". In late antiquity medical writing veered increasingly in the direction of the theoretical at the expense of the practical, with many authors merely debating Galenism. Magnus of Nisibis was a pure theorist, as were John of Alexandria and Agnellus of Ravenna with their lectures on Galen's De Sectis. So strong was Galenism that other authors such as Hippocrates began to be seen through a Galenic lens, while his opponents became marginalized and other medical sects such as Asclepiadism slowly disappeared. Greek medicine was part of Greek culture, and Syrian Eastern Christians came in contact with it while the Eastern Roman Empire (Byzantium) ruled Syria and Western Mesopotamia, regions that were conquered from Byzantium in the 7th century by Arab Muslims. After 750 AD, Muslims had these Syrian Christians make the first translations of Galen into Arabic. From then on Galen and the Greek medical tradition in general became assimilated into the medieval and early modern Islamic Middle East.

The first major translator of Galen into Arabic was the Syrian Christian Hunayn ibn Ishaq. Hunayn translated (c. 830 – 870) 129 works of "Jalinos" into Arabic. One of the Arabic translations, ‘Kitab ila Aglooqan fi Shifa al Amraz’, which is extant in the Library of Ibn Sina Academy of Medieval Medicine & Sciences, is regarded as a masterpiece of Galen's literary works. A part of the Alexandrian compendium of Galen’s work, this 10th century manuscript comprises two parts that include details regarding various types of fevers (Humyat) and different inflammatory conditions of the body. More importantly, it includes details of more than 150 single and compound formulations of both herbal and animal origin. The book provides an insight into understanding the traditions and methods of treatment in the Greek (Unani) and Roman eras. In addition, this book provides a direct source for the study of more than 150 single and compound drugs used during the Greco - Roman period.

Galen's insistence on a rational systematic approach to medicine set the template for Islamic medicine, which rapidly spread throughout the Arab Empire. Arabic sources, such as Rhazes (Muhammad ibn Zakarīya Rāzi 865 – 925 AD), continue to be the source of discovery of new or relatively inaccessible Galenic writings. As the title, Doubts on Galen by Rhazes implies, as well as the writings of physicians such as Ibn Zuhr (Avenzoar) and Ibn al-Nafis, the works of Galen were not accepted unquestioningly, but as a challengeable basis for further inquiry.

A strong emphasis on experimentation and empiricism led to new results and new observations, which were contrasted and combined with those of Galen by writers such as Rhazes, Ali ibn Abbas al-Majusi (Haly Abbas), Abu al-Qasim al-Zahrawi (Abulasis), Ibn Sina (Avicenna), Ibn Zuhr and Ibn al-Nafis. For example, the experiments carried out by Rāzi and Ibn Zuhr contradicted the Galenic theory of humorism, while Ibn al-Nafis' discovery of the pulmonary circulation contradicted the Galenic theory on the heart.

From the 11th century onwards, Latin translations of Islamic medical texts began to appear in the West, alongside the Salerno school of thought, and were soon incorporated into the curriculum at the universities of Naples and Montpellier. From that time, Galenism took on a new, unquestioned authority, Galen even being referred to as the "Medical Pope of the Middle Ages". Constantine the African was amongst those who translated both Hippocrates and Galen from Arabic. In addition to the more numerous translations of Arabic texts in this period, there were a few translations of Galenic works directly from the Greek, such as Burgundio of Pisa's translation of De complexionibus. Galen's works on anatomy and medicine became the mainstay of the medieval physician's university curriculum, alongside Ibn Sina's The Canon of Medicine which elaborated on Galen's works. Unlike pagan Rome, Christian Europe did not exercise a universal prohibition of the dissection and autopsy of the human body and such examinations were carried out regularly from at least the 13th century. However, Galen's influence, as in the Arab world, was so great that when dissections discovered anomalies compared with Galen's anatomy, the physicians often tried to fit these into the Galenic system. An example of this is Mondino de Liuzzi, who describes rudimentary blood circulation in his writings but still asserts that the left ventricle should contain air. Some cited these changes as proof that human anatomy had changed since the time of Galen.

The Renaissance and fall of the Byzantine Empire (1453) was accompanied by an influx of Greek scholars and manuscripts to the West, allowing direct comparison between the Arabic commentaries and the original Greek texts of Galen. This New Learning and the Humanist movement, particularly the work of Thomas Linacre, promoted literae humaniores including Galen in the Latin scientific canon, De Naturalibus Facultatibus appearing in London in 1523. Debates on medical science now had two traditions, the more conservative Arabian and the liberal Greek. The more extreme liberal movements began to challenge the role of authority in medicine, as exemplified by Paracelsus' symbolically burning the works of Avicenna and Galen at his medical school in Basle. Nevertheless Galen's pre - eminence amongst the great thinkers of the millennium is exemplified by a 16th century mural in the refectory of the Great Lavra of Mt Athos. It depicts pagan sages at the foot of the Tree of Jesse, with Galen between the Sibyl and Aristotle.

Galenism's final defeat came from a combination of the negativism of Paracelsus and the constructivism of the Italian Renaissance anatomists, such as Vesalius in the 16th century. In the 1530s, the Flemish anatomist and physician Andreas Vesalius took on a project to translate many of Galen's Greek texts into Latin. Vesalius' most famous work, De humani corporis fabrica, was greatly influenced by Galenic writing and form. Seeking to examine critically Galen's methods and outlook, Vesalius turned to human cadaver dissection as a means of verification. Galen's writings were shown by Vesalius to describe details present in monkeys but not in humans, and he demonstrated Galen's limitations through books and hands on demonstrations despite fierce opposition from orthodox pro - Galenists such as Jacobus Sylvius. Since Galen states that he is using observations of monkeys (human dissection was prohibited) to give an account of what the body looks like, Vesalius could portray himself as using Galen's approach of description of direct observation to create a record of the exact details of the human body, since he worked in a time when human dissection was allowed. Galen argued that monkey anatomy was close enough to humans for physicians to learn anatomy with monkey dissections and then make observations of similar structures in the wounds of their patients, rather than trying to learn anatomy only from wounds in human patients, as would be done by students trained by the Empiricist medical sect would. The examinations of Vesalius also disproved medical theories of Aristotle and Mondino de Liuzzi. One of the best known examples of Vesalius' overturning of Galenism was his demonstration that the interventricular septum of the heart was not permeable, as Galen had taught (Nat Fac III xv). However, this had been revealed two years before by Michael De Villeneuve (Michael Servetus) in his fateful "Christianismi restitutio" (1553).

Michael De Villanueva (Michael Servetus), Vesalius' fellow student, was the best Galenist at the University of Paris, according to Johann Winter von Andernach, who taught both. In the Galenism of the Renaissance, editions of the Opera Omnia by Galen were very important. It was begun in Venice in 1541 – 1542 by the Guinta. There were fourteen editions of the book from that date until 1625. Just one edition was produced from Lyon between 1548 and 1551. The Lyon edition has commentaries on breathing and blood streaming that correct the work of earlier renowned authors such as Vesalius, Caius or Janus Cornarius. Michael De Villeneuve had contracts with Jean Frellon for that work, and the Servetus scholar - researcher Francisco Javier González Echeverría presented research that became an accepted communication in the International Society for the History of Medicine which concluded that Michael De Villeneuve (Michael Servetus) is the author of the commentaries of this edition of Frellon, in Lyon.

Another convincing case where understanding of the body was extended beyond where Galen had left it came from these demonstrations of the nature of human circulation and the subsequent work of Andrea Cesalpino, Fabricio of Acquapendente and William Harvey. Some Galenic teaching, such as his emphasis on bloodletting as a remedy for many ailments, however remained influential until well into the 19th century.

Numerous “firsts” in medical research, clinical care and chemistry are attributed to him, including being the first to differentiate smallpox from measles, and the discovery of numerous compounds and chemicals including kerosene, among others. Edward Granville Browne considers him as "probably the greatest and most original of all the physicians, and one of the most prolific as an author".

Razi made fundamental and enduring contributions to the fields of medicine, alchemy, music and philosophy, recorded in over 200 books and articles in various fields of science. He was well versed in Persian, Greek and Indian medical knowledge and made numerous advances in medicine through own observations and discoveries.

Educated in music, mathematics, philosophy and metaphysics, he chose medicine as his professional field. As a physician, he was an early proponent of experimental medicine and has been described as the father of pediatrics. He was also a pioneer of ophthalmology. He was among the first to use Humoralism to distinguish one contagious disease from another. In particular, Razi was the first physician to distinguish smallpox and measles through his clinical characterization of the two diseases. He became chief physician of Rey and Baghdad hospitals.

As an alchemist, Razi is known for his study of sulfuric acid.

He traveled extensively, mostly in Persia. As a teacher in medicine, he attracted students of all disciplines and was said to be compassionate and devoted to the service of his patients, whether rich or poor.

Rhazes was born in the silk road passing city of Rey. His name Razi in Persian means "from the city of Rey", an ancient town called Ragha in old Persian and Ragâ in Avestan. It is located on the southern slopes of the Alborz Range situated near Tehran, Iran. In this city (like Ibn Sina) he accomplished most of his work.

He studied medicine under Ali ibn Sahl Rabban al-Tabari, known as Ali ibn Rabban al-Tabari or Ali ibn Sahl, (Cf. al-Qifti, Usaibi'ah), a physician and philosopher born in Merv about 192 AH (808 C.E.) (d. approx. 240 AH (855 C.E.)). Ali ibn Sahl belonged to the medical school of Tabaristan or Hyrcania).

Razi became famous in his native city as a physician. He became Director of the hospital of Rey (Cf. ibn Juljul, al-Qifti, ibn abi Usaibi'ah), during the reign of Mansur ibn Ishaq ibn Ahmad ibn Asad who was Governor of Rey from 290 - 296 AH (902 - 908 C.E.) on behalf of his cousin Ahmad ibn Isma'il ibn Ahmad, second Samanian ruler. Razi dedicated his al-Tibb al-'Mansuri to Mansur ibn Ishaq ibn Ahmad, which was verified in a handwritten manuscript of his book. This was refuted by ibn al-Nadim', but al-Qifti and ibn abi Usaibi'ah confirmed that the named Mansur was indeed Mansur ibn Isma'il who died in 365 AH (975 C.E.). Razi moved from Rey to Baghdad during Caliph Muktafi's reign (approx. 289 - 295 AH (901 - 907 C.E.)) where he again held a position as Chief Director of a hospital.

After al-Muktafi's death in 295 AH (907 C.E.) Razi allegedly returned to Rey where he gathered many students around him. As Ibn al-Nadim relates in Fihrist, Razi was then a Shaikh (title given to one entitled to teach), surrounded by several circles of students. When someone arrived with a scientific question, this question was passed on to students of the 'first circle'. If they did not know the answer, it was passed on to those of the 'second circle'... and so on and on, until at last, when all others had failed to supply an answer, it came to Razi himself. We know of at least one of these students who became a physician. Razi was a very generous man, with a humane behavior towards his patients, and acting charitable to the poor. He used to give them full treatment without charging any fee, nor demanding any other payment.

His eye affliction started with cataracts and ended in total blindness. The cause of his blindness is uncertain. One account attributes the cause to have been a blow to the head by his patron, al-Mansour. Abulfaraj (Historia Compendosia Dynastiarum, p.291) and Casiri claim that the cause was eating beans. Another attributes the cause of his blindness to a beating ordered by a mullah who was offended by his work, al-Hawi. The beating was administered with the manuscript of the work.

During that time he was approached by a physician offering an ointment to cure his blindness. Al-Razi then asked him how many layers does the eye contain and when he was unable to answer he refused his services and the ointment stating "my eyes will not be treated by one who does not know the basics of its anatomy". One of his pupils from Tabaristan came to look after him, but, according to al-Biruni, he refused to be treated, proclaiming it was useless as his hour of death was approaching. Some days later he died in Rey, on the 5th of Sha'ban 313 AH (27 October 925).

However, his fame spread and lived on. In an undated catalog of the library at Peterborough Abbey, most likely from the 14th century, he is listed as a part author of ten books on medicine.

Razi studied medicine under Ali ibn Rabban al-Tabari, however, Ibn al-Nadim indicates that he studied philosophy under al-Bakhi, who had traveled much and possessed great knowledge of philosophy and ancient sciences.

Razi's opponents, on the contrary, are well known. They are the following:

• Abu al-Rabban al-Balki, chief of the Mu'tazilah of Baghdad (d. 319 AH / 931 CE), a contemporary of Razi who wrote many refutations about Razi's books, especially in his Ilm al-Ilahi. His disagreements with Razi entailed his thoughts on the concept of 'Time'.
• Shuhaid ibn al-Husain al-Balkhi, with whom Razi had many controversies; one of these was on the concept of 'Pleasure', expounded in his Tafdll Ladhdhat al-Nafs which abu Sulaiman al-Mantiqi al-Sijistani quotes in his work Siwan al-Hikmah. Al-Balkhi died prior to 329 AH / 940 CE.
• Abu Hatim al-Razi (Ahmad ibn Hamdan, an Isma'ili missionary, was one of his most influential opponents (d. 322 AH / 933 - 934 CE). He published his controversies with Razi in his book A'lam al-Nubuwwah. Because of this book, Razi's thoughts on Prophets and Religion are preserved to the present time.
• Ibn al-Tammar (seemingly being abu Bakr Husain al-Tammar, according to Kraus) was a physician who had some disputes with Razi, as documented by Abu Hatim al-Razi in A'lam al-Nubuwwah. Ibn al-Tammar disagreed with Razi's book al-Tibb al-Ruhani but Razi rebutted him in two antitheses:

First refutation of al-Tammar's disagreement with Misma'i concerning 'Matter'.

Second refutation of al-Tammar's opinion of 'the Atmosphere of subterranean habitations'.

• Following are authors as described by Razi in his writings:
  • Al-Misma'i, a Mutakallim, who opposed 'materialists', counteracted Razi's treatise.
  • Jarir, a physician who had a theory about 'The eating of black mulberries after consuming watermelon'.
  • Al-Hasan ibn Mubarik al-Ummi, to whom Razi wrote two epistles with commentaries.
  • Al-Kayyal, a Mutakallim: al-Razi wrote a book on about his Theory of the Imam.
  • Mansur ibn Talhah, being the author of the book "Being", which was criticized by al-Razi.
  • Muhammad ibn al-Laith al-Rasa'ili whose opposition against alchemists was disputed by al-Razi.
• Ahmad ibn al-Tayyib al-Sarakhasi (d. 286 AH / 899 CE), was an older contemporary of al-Razi. Al-Razi disagreed with him on the question of 'bitter taste'. He moreover opposed his teacher Ya'qub ibn Ishaq al-Kindi, regarding his writings, in which he discredited alchemists.

More names could be added to this list of all people opposed by al-Razi, specifically the Mu'tazilah and different Mutakallimin.

"Smallpox appears when blood 'boils' and is infected, resulting in vapors being expelled. Thus juvenile blood (which looks like wet extracts appearing on the skin) is being transformed into richer blood, having the color of mature wine. At this stage, smallpox shows up essentially as 'bubbles found in wine' - (as blisters) - ... this disease can also occur at other times - (meaning: not only during childhood) -. The best thing to do during this first stage is to keep away from it, otherwise this disease might turn into an epidemic."

This diagnosis is acknowledged by the Encyclopaedia Britannica (1911), which states: "The most trustworthy statements as to the early existence of the disease are found in an account by the 9th century Persian physician Rhazes, by whom its symptoms were clearly described, its pathology explained by a humoral or fermentation theory, and directions given for its treatment."

Razi's book: al-Judari wa al-Hasbah (On Smallpox and Measles) was the first book describing smallpox and measles as distinct diseases. It was translated more than a dozen times into Latin and other European languages. Its lack of dogmatism and its Hippocratic reliance on clinical observation show Razi's medical methods. For example:

"The eruption of smallpox is preceded by a continued fever, pain in the back, itching in the nose and nightmares during sleep. These are the more acute symptoms of its approach together with a noticeable pain in the back accompanied by fever and an itching felt by the patient all over his body. A swelling of the face appears, which comes and goes, and one notices an overall inflammatory color noticeable as a strong redness on both cheeks and around both eyes. One experiences a heaviness of the whole body and great restlessness, which expresses itself as a lot of stretching and yawning. There is a pain in the throat and chest and one finds it difficult to breathe and cough. Additional symptoms are: dryness of breath, thick spittle, hoarseness of the voice, pain and heaviness of the head, restlessness, nausea and anxiety. (Note the difference: restlessness, nausea and anxiety occur more frequently with 'measles' than with smallpox. At the other hand, pain in the back is more apparent with smallpox than with measles). Altogether one experiences heat over the whole body, one has an inflamed colon and one shows an overall shining redness, with a very pronounced redness of the gums."

Razi is also known for having discovered "allergic asthma," and was the first physician to write articles on allergy and immunology. In the Sense of Smelling he explains the occurrence of rhinitis after smelling a rose during the Spring: Article on the Reason Why Abou Zayd Balkhi Suffers from Rhinitis When Smelling Roses in Spring. In this article he discusses seasonal rhinitis, which is the same as allergic asthma or hay fever. Razi was the first to realize that fever is a natural defense mechanism, the body's way of fighting disease.

Razi contributed in many ways to the early practice of pharmacy by compiling texts, in which he introduces the use of 'mercurial ointments' and his development of apparatus such as mortars, flasks, spatulas and phials, which were used in pharmacies until the early twentieth century .

On a professional level, Razi introduced many practical, progressive, medical and psychological ideas. He attacked charlatans and fake doctors who roamed the cities and countryside selling their nostrums and "cures". At the same time, he warned that even highly educated doctors did not have the answers to all medical problems and could not cure all sicknesses or heal every disease, which was humanly speaking impossible. To become more useful in their services and truer to their calling, Razi advised practitioners to keep up with advanced knowledge by continually studying medical books and exposing themselves to new information. He made a distinction between curable and incurable diseases. Pertaining to the latter, he commented that in the case of advanced cases of cancer and leprosy the physician should not be blamed when he could not cure them. To add a humorous note, Razi felt great pity for physicians who took care for the well being of princes, nobility, and women, because they did not obey the doctor's orders to restrict their diet or get medical treatment, thus making it most difficult being their physician.

He also wrote the following on medical ethics:

"The doctor's aim is to do good, even to our enemies, so much more to our friends, and my profession forbids us to do harm to our kindred, as it is instituted for the benefit and welfare of the human race, and God imposed on physicians the oath not to compose mortiferous remedies."

The Virtuous Life (al-Hawi الحاوي).

This monumental medical encyclopedia in nine volumes — known in Europe also as The Large Comprehensive or Continens Liber (جامع الكبير) — contains considerations and criticism on the Greek philosophers Aristotle and Plato, and expresses innovative views on many subjects. Because of this book alone, many scholars consider Razi the greatest medical doctor of the Middle Ages.

The al-Hawi is not a formal medical encyclopedia, but a posthumous compilation of Razi's working notebooks, which included knowledge gathered from other books as well as original observations on diseases and therapies, based on his own clinical experience. It is significant since it contains a celebrated monograph on smallpox, the earliest one known. It was translated into Latin in 1279 by Faraj ben Salim, a physician of Sicilian - Jewish origin employed by Charles of Anjou, and after which it had a considerable influence in Europe.

The al-Hawi also criticized the views of Galen, after Razi had observed many clinical cases which did not follow Galen's descriptions of fevers. For example, he stated that Galen's descriptions of urinary ailments were inaccurate as he had only seen three cases, while Razi had studied hundreds of such cases in hospitals of Baghdad and Rey.

A medical adviser for the general public (Man la Yahduruhu Al-Tabib) (من لا يحضره الطبيب)

Razi was possibly the first Persian doctor to deliberately write a home medical manual (remedial) directed at the general public. He dedicated it to the poor, the traveler, and the ordinary citizen who could consult it for treatment of common ailments when a doctor was not available. This book, of course, is of special interest to the history of pharmacy since similar books were very popular until the 20th century. Razi described in its 36 chapters, diets and drug components that can be found in either an apothecary, a market place, in well equipped kitchens, or and in military camps. Thus, every intelligent person could follow its instructions and prepare the proper recipes with good results.

Some of the illnesses treated were headaches, colds, coughing, melancholy and diseases of the eye, ear, and stomach. For example, he prescribed for a feverish headache: "2 parts of duhn (oily extract) of rose, to be mixed with 1 part of vinegar, in which a piece of linen cloth is dipped and compressed on the forehead". He recommended as a laxative, " 7 drams of dried violet flowers with 20 pears, macerated and well mixed, then strained. Add to this filtrate, 20 drams of sugar for a drink. In cases of melancholy, he invariably recommended prescriptions, which included either poppies or its juice (opium), Cuscuta epithymum (clover dodder) or both. For an eye remedy, he advised myrrh, saffron, and frankincense, 2 drams each, to be mixed with 1 dram of yellow arsenic formed into tablets. Each tablet was to be dissolved in a sufficient quantity of coriander water and used as eye drops.

Doubts About Galen (Shukuk 'ala alinusor)

In his book Doubts about Galen, Razi rejects several claims made by the Greek physician, as far as the alleged superiority of the Greek language and many of his cosmological and medical views. He links medicine with philosophy, and states that sound practice demands independent thinking. He reports that Galen's descriptions do not agree with his own clinical observations regarding the run of a fever. And in some cases he finds that his clinical experience exceeds Galen's.

He criticized moreover Galen's theory that the body possessed four separate "humors" (liquid substances), whose balance are the key to health and a natural body temperature. A sure way to upset such a system was to insert a liquid with a different temperature into the body resulting in an increase or decrease of bodily heat, which resembled the temperature of that particular fluid. Razi noted that a warm drink would heat up the body to a degree much higher than its own natural temperature. Thus the drink would trigger a response from the body, rather than transferring only its own warmth or coldness to it.

This line of criticism essentially had the potentiality to destroy completely Galen's Theory of Humours including Aristotle's theory of the Four Elements, on which it was grounded. Razi's own alchemical experiments suggested other qualities of matter, such as "oiliness" and "sulphurousness", or inflammability and salinity, which were not readily explained by the traditional fire, water, earth and air division of elements.

Razi's challenge to the current fundamentals of medical theory were quite controversial. Many accused him of ignorance and arrogance, even though he repeatedly expressed his praise and gratitude to Galen for his contributions and labors, saying:

"I prayed to God to direct and lead me to the truth in writing this book. It grieves me to oppose and criticize the man Galen from whose sea of knowledge I have drawn much. Indeed, he is the Master and I am the disciple. Although this reverence and appreciation will and should not prevent me from doubting, as I did, what is erroneous in his theories. I imagine and feel deeply in my heart that Galen has chosen me to undertake this task, and if he were alive, he would have congratulated me on what I am doing. I say this because Galen's aim was to seek and find the truth and bring light out of darkness. I wish indeed he were alive to read what I have published."

Crystallization of ancient knowledge, and the refusal to accept the fact that new data and ideas indicate that present day knowledge ultimately might surpass that of previous generations.

Razi believed that contemporary scientists and scholars are by far better equipped, more knowledgeable, and more competent than the ancient ones, due to the accumulated knowledge at their disposal. Razi's attempt to overthrow blind acceptance of the unchallenged authority of ancient sages encouraged and stimulated research and advances in the arts, technology and sciences.

The Diseases of Children

Razi is considered the father of pediatrics for writing The Diseases of Children, the first book to deal with pediatrics as an independent field of medicine.

Mental health

As many other theorists in his time of exploration of illnesses he believed that mental illnesses were caused by demons. Demons were believed to enter the body and possess the body. This shows that mental illnesses were understood to be out of the control of the sufferer.

Razi's interest in alchemy and his strong belief in the possibility of transmutation of lesser metals to silver and gold was attested half a century after his death by Ibn an-Nadim's book (The Philosophers Stone - Lapis Philosophorum in Latin). Nadim attributed a series of twelve books to Razi, plus an additional seven, including his refutation to al-Kindi's denial of the validity of alchemy. Al-Kindi (801 - 873 CE) had been appointed by the Abbasid Caliph Ma'mum founder of Baghdad, to 'the House of Wisdom' in that city, he was a philosopher and an opponent of alchemy.

Finally we will mention Razi's two best known alchemical texts, which largely superseded his earlier ones: al-Asrar (الاسرار "The Secrets"), and Sirr al-Asrar (سر الاسرار "The Secret of Secrets"), which incorporates much of the previous work.

Apparently Razi's contemporaries believed that he had obtained the secret of turning iron and copper into gold. Biographer Khosro Moetazed reports in Mohammad Zakaria Razi that a certain General Simjur confronted Razi in public, and asked whether that was the underlying reason for his willingness to treat patients without a fee. "It appeared to those present that Razi was reluctant to answer; he looked sideways at the general and replied":

"I understand alchemy and I have been working on the characteristic properties of metals for an extended time. However, it still has not turned out to be evident to me, how one can transmute gold from copper. Despite the research from the ancient scientists done over the past centuries, there has been no answer. I very much doubt if it is possible..."

According to one legend he could have been blinded by steaming vapors during an accident in one of his experiments. He managed to escape with no injuries.

Razi developed several chemical instruments that remain in use to this day. He is known to have perfected methods of distillation and extraction, which have led to his discovery of sulfuric acid, by dry distillation of vitriol (al-zajat), and alcohol (ethanol). These discoveries paved the way for other Persian alchemists, as did the discovery of various other mineral acids by Jabir Ibn Hayyan (known as Geber in Europe). As a pioneer of alchemy, Razi was the first to distill / refine petroleum and produce kerosene (later used as lamp oil and jet fuel).

ar-Razi dismissed the idea of potions and dispensed with magic, meaning the reliance on symbols as causes. Although Razi does not reject the idea that miracles exist, in the sense of unexplained phenomena in nature, his alchemical stockroom was enriched with products of Persian mining and manufacturing, even with sal ammoniac a Chinese discovery. He relied predominantly on the concept of 'dominant' forms or essences, which is the Neoplatonic conception of causality rather than an intellectual approach or a mechanical one. Razi's alchemy brings forward such empiric qualities as salinity and inflammability - the latter associated to 'oiliness' and 'sulphurousness'. These properties are not readily explained by the traditional composition of the elements such as: fire, water, earth and air, as al-óhazali and others after him were quick to note, influenced by critical thoughts such as Razi had.

Razi's achievements are of exceptional importance in the history of chemistry, since in his books we find for the first time a systematic classification of carefully observed and verified facts regarding chemical substances, reactions and apparatus, described in a language almost entirely free from mysticism and ambiguity. Razi's scheme of classification of the substances used in chemistry shows sound research on his part.

• The Secret (Al-Asrar)

This book was written in response to a request from Razi's close friend, colleague and former student, Abu Mohammed b. Yunis of Bukhara, a Muslim mathematician, philosopher, a highly reputable natural scientist.
In his book Sirr al-Asrar, Razi divides the subject of "Matter' into three categories as he did in his previous book al-Asrar.

1. Knowledge and identification of drug components of plant-, animal- and mineral - origin and the description of the best type of each for utilization in treatment.
2. Knowledge of equipment and tools of interest to and used by either alchemist or apothecary.
3. Knowledge of seven alchemical procedures and techniques: sublimation and condensation of mercury, precipitation of sulfur and arsenic calcination of minerals (gold, silver, copper, lead and iron), salts, glass, talc, shells and waxing.

This last category contains additionally a description of other methods and applications used in transmutation:
* The added mixture and use of solvent vehicles.
* The amount of heat (fire) used, 'bodies and stones', ('al-ajsad' and 'al-ahjar) that can or cannot be transmuted into corporal substances such of metals and Id salts ('al-amlah').
* The use of a liquid mordant which quickly and permanently colors lesser metals for more lucrative sale and profit.

Similar to the commentary on the 8th century text on amalgams ascribed to Al- Hayan (Jabir), Razi gives methods and procedures of coloring a silver object to imitate gold (gold leafing) and the reverse technique of removing its color back to silver. Gilding and silvering of other metals (alum, calcium salts, iron, copper and tutty) are also described, as well as how colors will last for years without tarnishing or changing. Behind these procedures one does not find a deceptive motive rather a technical and economic deliberation. This becomes evident from the author's quotation of market prices and the expressed triumph of artisan, craftsman or alchemist declaring the results of their efforts "to make it look exactly like gold!". However, another motive was involved, namely, to manufacture something resembling gold to be sold quickly so to help a good friend who happened to be in need of money fast. Could it be Razi's alchemical technique of silvering and gilding metals which convinced many Muslim biographers that he was first a jeweler before he turned to the study of alchemy?

Of interest in the text is Razi's classification of minerals into six divisions, showing his discussion a modern chemical connotation:

1. Four spirits (AL-ARWAH): mercury, sal ammoniac, sulfur and arsenic sulphate (orpiment and realgar).
2. Seven bodies (AL-AJSAD): silver, gold, copper, iron, black lead (plumbago), zinc (Kharsind) and tin.
3. Thirteen stones (AL-AHJAR): Pyrites marcasite (marqashita), magnesia, malachite, tutty Zinc oxide (tutiya), talcum, lapis lazuli, gypsum, azurite, magnesia, haematite (iron oxide), arsenic oxide, mica and asbestos and glass (then identified as made of sand and alkali of which the transparent crystal Damascene is considered the best),
4. Seven vitriols (AL-ZAJAT): alum (al-shabb الشب), and white (qalqadis القلقديس), black, red (suri السوري) and yellow (qulqutar القلقطار) vitriols (the impure sulfates of iron, copper, etc.), green (qalqand القلقند).
5. Seven borates: natron and impure sodium borate.
6. Eleven salts (AL-AMLAH): including brine, common (table) salt, ashes, naphtha, live lime and urine, rock, and sea salts. Then he separately defines and describes each of these substances and their top choice, best colors and various adulterations.

Razi gives also a list of apparatus used in alchemy. This consists of 2 classes:

1. Instruments used for the dissolving and melting of metals such as the Blacksmith's hearth, bellows, crucible, thongs (tongue or ladle), macerator, stirring rod, cutter, grinder (pestle), file, shears, descensory and semi - cylindrical iron mould.
2. Utensils used to carry out the process of transmutation and various parts of the distilling apparatus: the retort, alembic, shallow iron pan, potters kiln and blowers, large oven, cylindrical stove, glass cups, flasks, phials, beakers, glass funnel, crucible, alundel, heating lamps, mortar, cauldron, hair - cloth, sand- and water - bath, sieve, flat stone mortar and chafing - dish.

• Secret of Secrets (Sirr Al-asrar)

This is Razi's most famous book which has gained a lot of recognition in the West. Here he gives systematic attention to basic chemical operations important to the history of pharmacy.

On existence

Razi is known to have been a free thinking philosopher, since he was well trained in ancient Greek science and philosophy although his approach to chemistry was rather naturalistic. Moreover, he was well versed in the theory of music, as so many other scientists of that time.

Metaphysics

His ideas on metaphysics were also based on the works of the ancient Greeks:

"The metaphysical doctrine of Razi, insofar as it can be reconstructed, derives from his concept of the five eternal principles. God, for him, does not 'create' the world from nothing but rather arranges a universe out of pre - existing principles. His account of the soul features a mythic origin of the world in which God out of pity fashions a physical playground for the soul in response to its own desires; the soul, once fallen into the new realm God has made for it, requires God's further gift of intellect in order to find its way once more to salvation and freedom. In this scheme, intellect does not appear as a separate principle but is rather a later grace of God to the soul; the soul becomes intelligent, possessed of reason and therefore able to discern the relative value of the other four principles. Whereas the five principles are eternal, intellect as such is apparently not. Such a doctrine of intellect is sharply at odds with that of all of Razi's philosophical contemporaries, who are in general either adherents of some form of Neoplatonism or of Aristotelianism. The remaining three principles, space, matter and time, serve as the non - animate components of the natural world. Space is defined by the relationship between the individual particles of matter, or atoms, and the void that surrounds them. The greater the density of material atoms, the heavier and more solid the resulting object; conversely, the larger the portion of void, the lighter and less solid. Time and matter have both an absolute, unqualified form and a limited form. Thus there is an absolute matter - pure extent - that does not depend in any way on place, just as there is a time, in this sense, that is not defined or limited by motion. The absolute time of al-Razi is, like matter, infinite; it thus transcends the time which Aristotle confined to the measurement of motion. Razi, in the cases of both time and matter, knew well how he differed from Aristotle and also fully accepted and intended the consequences inherent in his anti - Peripatetic positions." (Paul E. Walker)

Excerpt from The Philosophical Approach

"(...) In short, while I am writing the present book, I have written so far around 200 books and articles on different aspects of science, philosophy, theology, and hekmat (wisdom). (...) I never entered the service of any king as a military man or a man of office, and if I ever did have a conversation with a king, it never went beyond my medical responsibility and advice. (...) Those who have seen me know, that I did not into excess with eating, drinking or acting the wrong way. As to my interest in science, people know perfectly well and must have witnessed how I have devoted all my life to science since my youth. My patience and diligence in the pursuit of science has been such that on one special issue specifically I have written 20,000 pages (in small print), moreover I spent fifteen years of my life - night and day - writing the big collection entitled Al Hawi. It was during this time that I lost my eyesight, my hand became paralyzed, with the result that I am now deprived of reading and writing. Nonetheless, I've never given up, but kept on reading and writing with the help of others. I could make concessions with my opponents and admit some shortcomings, but I am most curious what they have to say about my scientific achievement. If they consider my approach incorrect, they could present their views and state their points clearly, so that I may study them, and if I determined their views to be right, I would admit it. However, if I disagreed, I would discuss the matter to prove my standpoint. If this is not the case, and they merely disagree with my approach and way of life, I would appreciate they only use my written knowledge and stop interfering with my behavior."

"In the "Philosophical Biography", as seen above, he defended his personal and philosophical life style. In this work he laid out a framework based on the idea that there is life after death full of happiness, not suffering. Rather than being self - indulgent, man should pursue knowledge, utilise his intellect and apply justice in his life.
According to Al-Razi: "This is what our merciful Creator wants. The One to whom we pray for reward and whose punishment we fear."

In brief, man should be kind, gentle and just. Al-Razi believed that there is a close relationship between spiritual integrity and physical health. He did not implicate that the soul could avoid distress due to his fear of death. He simply states that this psychological state cannot be avoided completely unless the individual is convinced that, after death, the soul will lead a better life. This requires a thorough study of esoteric doctrines and/or religions. He focuses on the opinion of some people who think that the soul perishes when the body dies. Death is inevitable, therefore one should not pre-occupy the mind with it, because any person who continuously thinks about death will become distressed and think as if he is dying when he continuously ponders on that subject. Therefore, he should forget about it in order to avoid upsetting himself. When contemplating his destiny after death, a benevolent and good man who acts according to the ordinances of the Islamic Shari`ah, has after all nothing to fear because it indicates that he will have comfort and permanent bliss in the Hereafter. The one who doubts the Shari`ah, may contemplate it, and if he diligently does this, he will not deviate from the right path. If he falls short, Allah will excuse him and forgive his sins because it is not demanded of him to do something which he cannot achieve." (Dr. Muhammad Abdul - Hadi Abu Reidah)

On Religion

A number of contradictory works and statements about religion have been ascribed to Razi. According to al-Biruni's Bibliography of Razi (Risāla fī Fihrist Kutub al-Rāzī), Razi wrote two "heretical books": "Fī al-Nubuwwāt (On Prophecies) and "Fī Ḥiyal al-Mutanabbīn (On the Tricks of False Prophets). According to Biruni, the first "was claimed to be against religions" and the second "was claimed as attacking the necessity of the prophets." In his Risala, Biruni further criticized and expressed caution about Razi's religious views, noting an influence of Manichaeism. However, Biruni also listed some other works of Razi on religion, including Fi Wujub Da‘wat al-Nabi ‘Ala Man Nakara bi al-Nubuwwat (Obligation to Propagate the Teachings of the Prophet Against Those who Denied Prophecies) and Fi anna li al-Insan Khaliqan Mutqinan Hakiman (That Man has a Wise and Perfect Creator), among others, listed under his works on the "divine sciences". None of these works are now extant.

Other views and quotes that are often ascribed to Razi are found in a book written by Abu Hatim al-Razi, called Aʿlām al-nubuwwa, and not in any extant work of Razi. Abu Hatim was an Isma'ili missionary who debated Razi, but whether he has faithfully recorded the views of Razi is disputed. According to Abdul Latif al-'Abd, Islamic philosophy professor at Cairo University, Abu Hatim and his student, Ḥamīd al-dīn Karmānī (d. 411AH), were Isma'ili extremists who often misrepresented the views of Razi in their works. This view is also corroborated by early historians like al-Shahrastani who noted "that such accusations should be doubted since they were made by Ismāʿīlīs, who had been severely attacked by Muḥammad ibn Zakariyyā Rāzī". Al-'Abd also points out that the views allegedly expressed by Razi contradict what is found in Razi's own works, like the Spiritual Medicine (Fī al-ṭibb al-rūḥānī). Al-'Abd considers the content of the Spiritual Medicine to be a refutation to the claims made by Abu Hatim about Razi's religious views.

According to Abu Hatim, Razi offered harsh criticism concerning religions, in particular those religions that claim to have been revealed by prophetic experiences. Razi asserted that "[God] should not set some individuals over others, and there should be between them neither rivalry nor disagreement which would bring them to perdition." He argued,

On what ground do you deem it necessary that God should single out certain individuals [by giving them prophecy], that he should set them up above other people, that he should appoint them to be the people's guides, and make people dependent upon them?

Concerning the link between violence and religion, Razi expressed that God must have known, considering the many disagreements between different religions, that "there would be a universal disaster and they would perish in the mutual hostilities and fighting. Indeed, many people have perished in this way, as we can see."

He was also critical of the lack of interest among religious adherents in the rational analysis of their beliefs, and the violent reaction which takes its place:

If the people of this religion are asked about the proof for the soundness of their religion, they flare up, get angry and spill the blood of whoever confronts them with this question. They forbid rational speculation, and strive to kill their adversaries. This is why truth became thoroughly silenced and concealed.

Al-Razi believed that common people had originally been duped into belief by religious authority figures and by the status quo. He believed that these authority figures were able to continually deceive the common people "as a result of [religious people] being long accustomed to their religious denomination, as days passed and it became a habit. Because they were deluded by the beards of the goats, who sit in ranks in their councils, straining their throats in recounting lies, senseless myths and "so-and-so told us in the name of so-and-so..."

He believed that the existence of a large variety of religions was, in itself, evidence that they were all man made, saying, "Jesus claimed that he is the son of God, while Moses claimed that He had no son, and Muhammad claimed that he [Jesus] was created like the rest of humanity." and "Mani and Zoroaster contradicted Moses, Jesus and Muhammad regarding the Eternal One, the coming into being of the world, and the reasons for the [existence] of good and evil." In relation to the Hebrew's God asking of sacrifices, he said that "This sounds like the words of the needy rather than of the Laudable Self - sufficient One."

On the Qur'an, Razi said:

You claim that the evidentiary miracle is present and available, namely, the Koran. You say: "Whoever denies it, let him produce a similar one." Indeed, we shall produce a thousand similar, from the works of rhetoricians, eloquent speakers and valiant poets, which are more appropriately phrased and state the issues more succinctly. They convey the meaning better and their rhymed prose is in better meter. ... By God what you say astonishes us! You are talking about a work which recounts ancient myths, and which at the same time is full of contradictions and does not contain any useful information or explanation. Then you say: "Produce something like it"?!

The above is a translation of a quote from Mohammad Ibn Zakariya al-Razi's now lost treatise, Mahariq al anbiya مخارق الانبياء (The Prophets' Fraudulent Tricks), in Abu Hatim al-Razi's refutation, A'lam al-Nubuwwah (Signs of Prophecy). Another, longer, translation of the same passage is also available.

From the beginning of the human history, all of those who claimed to be prophets were, in his worst assumption, tortuous and devious and with his best assumption had psychological problems.

Al-Razi's religious and philosophical views were later criticized by Persian Islamic philosophers such as Abu Rayhan Biruni and Avicenna in the early 11th century. Biruni in particular wrote a short Risala treatise dealing with al-Razi, criticizing him for his sympathy with Manichaeism, his Hermetical writings, his religious and philosophical views, for refusing to mathematize physics, and his active opposition to mathematics. Avicenna, who was himself a physician and philosopher, also criticized al-Razi. During a debate with Biruni, Avicenna stated:

Or from Muhammad ibn Zakariyyab al-Razi, who meddles in metaphysics and exceeds his competence. He should have remained confined to surgery and to urine and stool testing — indeed he exposed himself and showed his ignorance in these matters.

"Rhazes was the greatest physician of Islam and the Medieval Ages." –  George Sarton

"Rhazes remained up to the 17th century the indisputable authority of medicine." –  The Encyclopaedia of Islam

"His writings on smallpox and measles show originality and accuracy, and his essay on infectious diseases was the first scientific treatise on the subject." – The Bulletin of the World Health Organization (May 1970)

"In today's world we tend to see scientific advance as the product of great movements, massive grant funded projects, and larger - than - life socio - economic forces. It is easy to forget, therefore, that many contributions stemmed from the individual efforts of scholars like Rhazes. Indeed, pharmacy can trace much of its historical foundations to the singular achievements of this ninth - century Persian scholar." — Michael E. Flannery

The modern-day Razi Institute in Tehran, and Razi University in Kermanshah were named after him, and 'Razi Day' ('Pharmacy Day') is commemorated in Iran every August 27.