Encyclopedia of the Brethren of Purity
The writings of the brothers, left title page, scene: authors in their milieu
|Author||Brethren of Purity|
|Original title||رسائل إخوان الصفاء وخِلَّان الوفاء|
The Encyclopedia of the Brethren of Purity (Arabic: رسائل إخوان الصفا) also variously known as the Epistles of the Brethren of Sincerity, Epistles of the Brethren of Purity and Epistles of the Brethren of Purity and Loyal Friends was a large encyclopedia in 52 treatises (rasā'il) written by the mysterious Brethren of Purity of Basra, Iraq sometime in the second half of the 10th century CE (or possibly later, in the 11th century). It had a great influence on later intellectual leading lights of the Muslim world, such as Ibn Arabi, and was transmitted as far abroad within the Muslim world as Al-Andalus. The Encyclopedia contributed to the popularization and legitimization of Platonism in the Islamic world.
The identity and period of the authors of the Encyclopedia have not been conclusively established, though the work has been mostly linked with the Isma'ilis. Idris Imad al-Din, a prominent 15th-century Isma'ili missionary in Yemen, credited the authorship of the encyclopedia to Ahmad b. 'Abd Allah b. Muhammad b. Ismail b. Ja'far as-Sadiq, the 9th Isma'ili imam who lived in occultation in the era of Abbasids, at the beginning of the Islamic Golden Age. Some suggest that besides Ismailism, the Brethren of Purity also contains elements of Sufism, Mu'tazilism, Nusairism, Rosicrucianism, etc.
The subject of the work is vast and ranges from mathematics, music, astronomy, and natural sciences, to ethics, politics, religion, and magic—all compiled for one, basic purpose, that learning is training for the soul and a preparation for its eventual life once freed from the body.
Turn from the sleep of negligence and the slumber of ignorance, for the world is a house of delusion and tribulations. – Encyclopedia of the Brethren of Sincerity
Authorship of the Encyclopedia is usually ascribed to the mysterious "Brethren of Purity" a group of Ismaili scholars placed in Basra, Iraq sometime around 10th century CE . While it is generally accepted that it was the group who authored at least the 52 rasa'il, the authorship of the "Summary" (al-Risalat al-Jami'a) is uncertain; it has been ascribed to the later Majriti but this has been disproved by Yves Marquet (see the Risalat al-Jami'a section). Since style of the text is plain, and there are numerous ambiguities, due to language and vocabulary, often of Persian origin, it has been suggested that the authors of the encyclopedia were of Persian descent.
Some philosophers and historians such as Tawhidi, Ibn al-Qifti, Shahrazuri disclosed the names of those allegedly involved in the development of the work: Abu Sulayma Bisti, Muqaddasi, 'Ali ibn Harun, Zanjani, Muahmmad ibn Ahmad Narhruji, 'Awfi. All these people are according to Henry Corbin, Ismailis
Further perplexities abound; the use of pronouns for the authorial "sender" of the rasa'il is not consistent, with the writer occasionally slipping from third person to first-person (for example, in Epistle 44, "The Doctrine of the Sincere Brethren"). This has led some to suggest that the rasa'il were not in fact written co-operatively by a group or consolidated notes from lectures and discussions, but were actually the work of a single person. Of course, if one accepts the longer time spans proposed for the composition of the Encyclopedia, or the simpler possibility that each risala was written by a separate person, sole authorship would be impossible.
The subject matter of the Rasa'il is vast and ranges from mathematics, music, logic, astronomy, the physical and natural sciences, as well as exploring the nature of the soul and investigating associated matters in ethics, revelation, and spirituality.
Its philosophical outlook was Neoplatonic and it tried to integrate Greek philosophy (and especially the dialectical reasoning and logic of Aristotelianism) with various astrological, Hermetic, Gnostic and Islamic schools of thought. Scholars have seen Ismaili and Sufi influences in the religious content, and Mu'tazilite acceptance of reasoning in the work. Others, however, hold the Brethren to be "free-thinkers" who transcended sectarian divisions and were not bound by the doctrines of any specific creed.
Their unabashed eclecticism is fairly unusual in this period of Arabic thought, characterised by fierce theological disputes; they refused to condemn rival schools of thought or religions, instead insisting that they be examined fairly and open-mindedly for what truth they may contain:
...to shun no science, scorn any book, or to cling fanatically to no single creed. For [their] own creed encompasses all the others and comprehends all the sciences generally. This creed is the consideration of all existing things, both sensible and intelligible, from beginning to end, whether hidden or overt, manifest or obscure . . . in so far as they all derive from a single principle, a single cause, a single world, and a single Soul." - (from the Ikhwan al-Safa, or Encyclopedia of the Brethren of Purity; Rasa'il IV, pg 52) 
In total, they cover most of the areas an educated person was expected to understand in that era. The epistles (or "rasa'il") generally increase in abstractness, finally dealing with the Brethren's somewhat pantheistic philosophy, in which each soul is an emanation, a fragment of a universal soul with which it will reunite at death; in turn, the universal soul will reunite with Allah on Doomsday. The epistles are intended to transmit right knowledge, leading to harmony with the universe and happiness.
Organizationally, it is divided into 52 epistles. The 52 rasa'il are subdivided into four sections, sometimes called books (indeed, some complete editions of the Encyclopedia are in four volumes); in order, they are: 14 on the Mathematical Sciences, 17 on the Natural Sciences, 10 on the Psychological and Rational Sciences, 11 on Theological Sciences.
The division into four sections is no accident; the number four held great importance in Neoplatonic numerology, being the first square number and for being even. Reputedly, Pythagoras held that a man's life was divided into four sections, much like a year was divided into four seasons. The Brethren divided mathematics itself into four sections: arithmetic was Pythagoras and Nicomachus' domain; Ptolemy ruled over astronomy with his Almagest; geometry was associated with Euclid, naturally; and the fourth and last division was that of music. The fours did not cease there- the Brethren observed that four was crucial to a decimal system, as ; numbers themselves were broken down into four orders of magnitude: the ones, tens, hundreds, and thousands; there were four winds from the four directions (north, south, east, west); medicine concerned itself with the four humours, and natural philosophers with the four elements of Empedocles.
Another possibility, suggested by Netton is that the veneration for four stems instead from the Brethren's great interest in the Corpus Hermeticum of Hermes Trismegistus (identified with the god Hermes, to whom the number four was sacred); that hermetic tradition's magical lore was the main subject of the 51st rasa'il.
Netton mentions that there are suggestions that the 52nd risalah (on talismans and magic) is a later addition to the Encyclopedia, because of intertextual evidence: a number of the rasa'il claim that the total of rasa'il is 51. However, the 52nd risalah itself claims to be number 51 in one area, and number 52 in another, leading to the possibility that the Brethren's attraction for the number 51 (or 17 times 3; there were 17 rasa'il on natural sciences) is responsible for the confusion. Seyyed Hossein Nasr suggests that the origin of the preference for 17 stemmed from the alchemist Jābir ibn Hayyān's numerological symbolism.
Besides the fifty-odd epistles, there exists what claims to be overarching summary of the work, which is not counted in the 52, called "The Summary" (al-Risalat al-Jami'a) which exists in two versions. It has been claimed to have been the work of Majriti (d. circa 1008), although Netton states Majriti could not have composed it, and that Yves Marquet concludes from a philological analysis of the vocabulary and style in his La Philosophie des Ihwan al-Safa (1975) that it had to have been composed at the same time as the main corpus.
Like conventional Arabic Islamic works, the Epistles have no lack of time-worn honorifics and quotations from the Qur'an, but the Encyclopedia is also famous for some of the didactic fables it sprinkled throughout the text; a particular one, the "Island of Animals" or the "Debate of Animals" (embedded within the 22nd rasa'il, titled "On How The Animals and their Kinds are Formed"), is one of the most popular animal fables in Islam. The fable concerns how 70 men, nearly shipwrecked, discover an island where animals ruled, and began to settle on it. They oppressed and killed the animals, who unused to such harsh treatment, complained to the King (or Shah) of Djinns. The King arranged a series of debates between the humans and various representatives of the animals, such as the nightingale, the bee, and the jackal. The animals nearly defeat the humans, but an Arabian ends the series by pointing out that there was one way in which humans were superior to animals and so worthy of making animals their servants: they were the only ones Allah had offered the chance of eternal life to. The King was convinced by this argument, and granted his judgement to them, but strongly cautioned them that the same Qur'an that supported them also promised them hellfire should they mistreat their animals.
More metaphysical were the four ranks (or "spiritual principles"), which apparently were an elaboration of Plotinus' triad of Thought, Soul, and the One, known to the Brethren through The Theology of Aristotle (a version of Plotinus' Enneads in Arabic, modified with changes and paraphrases, and attributed to Aristotle); first, the Creator (al-Bārī) emanated down to Universal Intellect (al-'Aql al-Kullī), then to Universal Soul (al-Nafs), and through Prime Matter (al-Hayūlā al-Ūlā), which emanated still further down through (and creating) the mundane hierarchy. The mundane hierarchy consisted of Nature (al-Tabī'a), the Absolute Body (al-Jism al-Mutlaq), the Sphere (al-Falak), the Four Elements (al-Arkān), and the Beings of this world (al-Muwalladāt) in their three varieties of animals, minerals, and vegetables, for a total hierarchy of nine members. Furthermore, each member increased in subdivisions proportional to how far down in the hierarchy it was, for instance, Sphere, being number seven has the seven planets as its members.
The Absolute Body is also a form in Prime Matter as we explained in the Chapter on Matter. Prime Matter is a spiritual form which emanated from the Universal Soul. The Universal Soul also is a spiritual form which emanated from the Universal Intellect which is the first thing the Creator Created."  Not all Pythagorean doctrines were followed, however. The Brethren argued strenuously against transmigration of the soul. Since they refused to accept transmigration, then the Platonic idea that all learning is "remembrance" and that man can never attain to complete knowledge whilst shackled in his body must be false; the Brethren's stance was rather that a person could potentially learn everything worth knowing and avoid the snares and delusion of this sinful world, eventually attaining to Paradise, Allah, and salvation, but unless they studied wise men and wise books - like their encyclopedia, whose sole purpose was to entice men to learn its knowledge and possibly be saved - that possibility would never become an actuality. As Netton writes, "The magpie eclecticism with which they surveyed and utilized elements from the philosophies of Pythagoras, Plato, Aristotle and Plotinus, and religions such as Nestorian Christianity, Judaism and Hinduism, was not an early attempt at ecumenism or interfaith dialogue. Their accumulation of knowledge was ordered towards the sublime goal of salvation. To use their own image, they perceived their Brotherhood, to which they invited others, as a "Ship of Salvation" that would float free from the sea of matter; the Ikhwan, with their doctrines of mutual cooperation, asceticism, and righteous living, would reach the gates of Paradise in its care."
Another area in which the Brethren differed was in their conceptions of nature, in which they rejected the emanation of Forms that characterized Platonic philosophy for a quasi-Aristotelian system of substances:
Know, O brother, that the scholars have said that all things are of two types, substances and accidents, and that all substances are of one kind and self-existent, while accidents are of nine kinds, present in the substances, and they are attributes of them. But the Creator may not be described as either accident or substance, for He is their Creator and efficient cause.
The first thing which the Creator produced and called into existence is a simple, spiritual, extremely perfect and excellent substance in which the form of all things is contained. This substance is called the Intellect. From this substance proceeds a second one which in hierarchy is below the first and is called the Universal Soul (al-nafs al-kullīyah). From the Universal Soul proceeds another substance which is below the Soul and which is called Original Matter. The latter is transformed into the Absolute Body, that is, into Secondary Matter which has length, width and depth." 
The 14th edition (EB-2:187a; 14th Ed., 1930) of the Encyclopædia Britannica described the mingling of Neoplatonism and Aristotelianism this way:
The materials of the work come chiefly from Aristotle, but they are conceived of in a Platonizing spirit, which places as the bond of all things a universal soul of the world with its partial or fragmentary souls."
The text in the "Encyclopedia of the Brethren of Purity" describes biological diversity in a manner similar to the modern day theory of evolution. The contexts of such passages are interpreted differently by scholars.
In this document some modern day scholars note that “chain of being described by the Ikhwan possess a temporal aspect which has led certain scholars to view that the authors of the Rasai’l believed in the modern theory of evolution”. According to the Rasa’il “But individuals are in perpetual flow; they are neither definite nor preserved. The reason for the conservation of forms, genus and species in matter is fixity of their celestial cause because their efficient cause is the Universal Soul of the spheres instead of the change and continuous flux of individuals which is due to the variability of their cause”. This statement is supporting the concept that species and individuals are not static, and that when they change it is due to a new purpose given. In the Ikhwan doctrine there are similarities between that and the theory of evolution. Both believe that “the time of existence of terrestrial plants precedes that of animals, minerals precede plants, and organism adapt to their environment”, but asserts that everything exists for a purpose.
"[These books] state that God first created matter and invested it with energy for development. Matter, therefore, adopted the form of vapour which assumed the shape of water in due time. The next stage of development was mineral life. Different kinds of stones developed in course of time. Their highest form being mirjan (coral). It is a stone which has in it branches like those of a tree. After mineral life evolves vegetation. The evolution of vegetation culminates with a tree which bears the qualities of an animal. This is the date-palm. It has male and female genders. It does not wither if all its branches are chopped but it dies when the head is cut off. The date-palm is therefore considered the highest among the trees and resembles the lowest among animals. Then is born the lowest of animals. It evolves into an ape. This is not the statement of Darwin. This is what Ibn Maskawayh states and this is precisely what is written in the Epistles of Ikhwan al-Safa. The Muslim thinkers state that ape then evolved into a lower kind of a barbarian man. He then became a superior human being. Man becomes a saint, a prophet. He evolves into a higher stage and becomes an angel. The one higher to angels is indeed none but God. Everything begins from Him and everything returns to Him."
English translations of the Encyclopedia of the Brethren of Purity were available from 1812, hence this work may have had an influence on Charles Darwin and his inception of Darwinism. However Hamidullah's "Darwin was inspired by the Epistles of the Ihkwan al-Safa" theory sounds unlikely as Charles Darwin comes from an evolutionist family with his well-known physician grandfather, Erasmus Darwin, author of the poem The Origin of Society on evolution, was one of the leading Enlightenment evolutionists.
The 48th epistle of the Encyclopedia of the Brethren of Purity features a fictional Arabic narrative. It is an anecdote of a "prince who strays from his palace during his wedding feast and, drunk, spends the night in a cemetery, confusing a corpse with his bride. The story is used as a gnostic parable of the soul's pre-existence and return from its terrestrial sojourn".
Editions and translations
Complete editions of the encyclopedia have been printed at least three times:
- Kitāb Ikhwān al-Ṣafā' (edited by Wilayat Husayn, Bombay 1888)
- Rasā'il Ikhwān al-Ṣafā' (edited by Khayr al-din al-Zarkali with introductions by Tāha Ḥusayn and Aḥmad Zakī Pasha, in 4 volumes, Cairo 1928)
- Rasā'il Ikhwān al-Ṣafā' (4 volumes, Beirut: Dār Ṣādir 1957)
The Encyclopedia has been widely translated, appearing not merely in its original Arabic, but in German, English, Persian, Turkish, and Hindustani. Although portions of the Encyclopedia were translated into English as early as 1812, with the Rev. T. Thomason's prose English introduction to Shaikh Ahmad b. Muhammed Shurwan's Arabic edition of the "Debate of Animals" published in Calcutta, a complete translation of the Encyclopedia into English does not exist as of 2006, although Friedrich Dieterici (Professor of Arabic in Berlin) translated the first 40 of the epistles into German; presumably, the remainder have since been translated. The "Island of Animals" have been translated several times in differing completion; the fifth risalah, on music, has been translated into English as have the 43rd through the 47th epistles.
The first complete Arabic critical edition and fully annotated English translation of the Rasa’il Ikhwan al-Safa’ with commentaries is being published by a team of experts as editors, translators and scholars. This constitutes a philosophy bi-lingual book series that is published by Oxford University Press in association with the Institute of Ismaili Studies in London; and this large-scale project is chaired by the series General Editor Nader El-Bizri.  This book series was initiated by an introductory volume of studies edited by Nader El-Bizri, which was published by Oxford University Press in 2008, and followed in 2009 by the voluminous Arabic critical edition and annotated English translation with commentaries of The Case of the Animals Versus Man Before the King of the Jinn (Epistle 22). - Additional volumes have since been published: ‘On Logic’ (Eps. 10-14; 2010), ‘On Music’ (Ep. 5; 2010), ‘On Magic’ (Ep. 52a; 2011); 'On Arithmetic and Geometry' (Eps. 1-2; 2012); 'On the Natural Sciences' (Eps. 15-21; 2013), 'On Geography' (Ep. 4; 2014), 'On Astronomia' (Ep. 3; 2015).  The scientific value of the Institute of Ismaili Studies is a point at issue.
- "The work only professes to be an epitome, an outline; its authors lay claim to no originality, they only summarize what others have thought and discovered. What they do lay claim to is system and completeness. The work does profess to contain a systematized, harmonious and co-ordinated view of the universe and life, its origin and destiny, formed out of many discordant, incoherent views; and it does claim to be a 'complete account of all things' - to contain, in epitome, all that was known at the time it was written. It refers to more profound and special treatises for fuller information on the several sciences it touches upon, but it does claim to touch on all sciences, all departments of knowledge, and to set forth their leading results. In effect, it is, by its own showing, a 'hand-encyclopedia of Arabian philosophy in the tenth century'. It is not easy to exaggerate the importance of this encyclopedia. Its value lies in its completeness, in its systematizing of the results of Persian study." Stanley Lane-Poole (1883), pages 190, 191.
- "Having been hidden within the cloak of secrecy from its very inception, the Rasa'il have provided many points of contention and have been a constant source of dispute among both Muslim and Western scholars. The identification of the authors, or possibly one author, the place and time of writing and propagation of their works, the nature of the secret brotherhood the outer manifestation of which comprises the Rasa'il - these and many secondary questions have remained without answer." Nasr (1964), pg 25.
- "It is probable that they have influenced some of the most prominent thinkers of Islam, such as al-Ghazzali (d. 1111A.D.) and Ibn al-Arabi (d. 1240 A.D.)." van Reijn (1995), pg. "v".
- "The Rasa'il were widely read by most learned men of later periods, including Ibn Sina and al-Ghazzali, have continued to be read up to our own times, and have been translated into Persian, Turkish, and Hindustani. From the number of manuscripts present in various libraries in the Muslim world, it must be considered among the most popular of Islamic works on learning." Nasr (1964), pg. 36
- Van Reijn (1945), pg "v"
- "But they produced this enormous encyclopaedia, and um, everybody read it and we know that it was widely read by mathematicians in Spain, and by philosophers in Spain. Most crucially of all, it was read by Muhyi-I-din - Ibn al-Arabi, er, the most famous Sufi that Spain produced, or indeed one of the most famous Sufis in the history of Islamic mysticism - er, he died in 1240. Er, he absorbed a lot of their ideas and he was in turn read by these ministers of the Nasrid monarch Ibn al-Khatib, and Ibn al-Zamrak, both of whom had strong, mystical tendencies." Robert Irwin; "In the Footsteps of Muhammad", transcript of a BBC program
- "George Sales observes that this uncreated Qur'an is nothing but its idea or Platonic archetype; it is likely that al-Ghazali used the idea of archetypes, communicated to Islam by the Encyclopedia of the Brethren of Purity and by Avicenna to justify the notion of the Mother of the Book." From "On the Cult of Books", Selected Non-Fictions, Jorge Luis Borges; ed. Eliot Weinberger, trans. Ester Allen, Suzanne Jill Levine, and Eliot Weinberger; 1999. ISBN 0-670-84947-2. See: Origin and development of the Qur'an#"Created" vs. "uncreated" Qur'an for the concept of the "uncreated Qur'an".
- Ikhwan as-Safa'. (2007). In Encyclopædia Britannica. Retrieved April 25, 2007, from Encyclopædia Britannica Online
- Leaman, Oliver, ed. (2015). "Ikhwan al-Safa'". The Biographical Encyclopedia of Islamic Philosophy. Bloomsbury Publishing. ISBN 9781472569455. Retrieved 4 Jun 2020 – via books.google.com.
- Brethren of Purity, Nader El-Bizri, an article in Medieval Islamic Civilization, an Encyclopedia, Vol. I, p. 118-119, Routledge (New York-London, 2006). Retrieved from .
- "Ibn al-Qifti, giving his own view, considers the Ikhwan as followers of the school of the Mu'tazilah...Ibn Tamiyah, the Hanbali jurist, on the other hand, tends towards the other extreme in relating the Ikhwan to the Nusairis, who are as far removed from the rationalists as any group to be found in Islam." Nasr (1964), pg 26.
- Isma'ili, Yezidi, Sufi. "The Brethren Of Purity". Retrieved 2006-05-17.CS1 maint: multiple names: authors list (link)
- Walker, Paul E. "EḴWĀN AL-ṢAFĀʾ". In Encyclopædia Iranica. December 15, 1998.
- Rasa'il Ikhwan al-Safa', 4 volumes (Beirut, Dar Sadir, 1957). A complete untranslated edition of the 52 rasa'il.
- Diana, Steigerwald (2015). Imamology in Ismaili Gnosis. New Delhi 110 002: Monahar Publishers $ Distributors. p. 141. ISBN 978-93-5098-081-1.CS1 maint: location (link)
- Ikhwan al-Safa', Routledge Encyclopaedia of Philosophy
- "Not everyone accepts the contemporary evidence that gives the Brethren as inhabitants of Basra. V. A. Ivanov, in The Alleged Founders of Ismailism (Bombay, 1946), says that "I would be inclined to think that this was a kind of camouflage story being circulated by the Ismailis to avoid the book being used as a proof of their orthodoxy. [sic]". As quoted by Nasr (1964), pg 29.
- Baffioni, Carmela. "Ikhwân al-Safâ’", The Stanford Encyclopedia of Philosophy (Summer 2012 Edition), Edward N. Zalta (ed.), First published April 22, 2008; Retrieved May 12, 2012.
- Baffioni, Carmela (2016). Zalta, Edward N. (ed.). The Stanford Encyclopedia of Philosophy (Fall 2016 ed.). Metaphysics Research Lab, Stanford University.
- "The Prophets and those of the Philosophers who have the right view...maintain that the body is only a prison of the soul, or a veil, an intermediary path or an isthmus...The sages of India called Brahmins cremate the bodies of the dead, but ignorant and cunning as they are, they do not do it for the reasons I have given. It would be proper to say that the term "sages" applies to only a few among them." van Reijn (1995), pages 24-25.
- "Ikhwan as-Safa and their Rasa'il: A Critical Review of a Century and a Half of Research", by A. L. Tibawi, as published in volume 2 of The Islamic Quarterly in 1955; pgs. 28-46
- From the introduction of Muslim Neoplatonists: An Introduction to the Thought of the Brethren of Purity, Ian Richard Netton, 1991. Edinburgh University Press, ISBN 0-7486-0251-8
- Some have claimed that the Brethren were Ismaili, though this may be unlikely because of their very lukewarm embrace of the Imamate and other aspects of Ismailian theology, in addition to the lack of solid evidence in favor of such a hypothesis.
- This is not to say that there aren't some suggestive links between the Brethren and the Isma'ili. Heinz Halm notes in his "The cosmology of the pre-Fatimid Isma'iliyya" (as printed in Medieval Isma'ili History and Thought, ed. Farhad Daftary, 1996, ISBN 0-521-45140-X) that the Sunni theologian Ibn Taymiyya (d. 1328) asserted that the doctrines of the Brethren were exactly identical to the Ismaili's in one of his fatwas. Halm further notes that Paul Casanova had shown that the infamous Hashshashin had approved of the Encyclopedia and that their missionaries in Yemen even made use of it. Other sects apparently drew upon the Encyclopedia as well: "The theological treatises of the Tayyibi Ismailis of the Yemen contain ample quotations from the Rasa'il Ikhwan al-Safa', and in the 'Uyun al-akhbar by the Yemenite da'i Idris 'Imad al-Din (d. 1468), Ahmad b. 'Abd Allah b. Muhammad b. Isma'il b. Ja'far al-Sadiq, the ninth imam and the second of the leaders of the Isma'ili da'wa residing in Salamiyya, is explicitly named as the author as the Rasa'il." (pg 76) Indeed, the respect of some Ismaili was great indeed, some referring to it as "a Quran after the Quran" (Nasr, 1964, pg. 26). V. A. Ivanov remarks in his The Alleged Founders of Ismailism (Bombay, 1946), that "the work is accepted by the Isma'ili as belonging to their religion, and is still regarded as esoteric..."
- But there are more reasons to reject an identification of the Brethren with Isma'ili, such as the failure of Hamid al-Din al-Kirmani, an extremely important Islamic theologian, to make any mention of them. And other authors agree with this: "...the well-known modern Isma'ili scholar, H. F. al-Hamdani, although emphasizing the importance of the Rasa'il in the Isma'ili mission in the Yemen, disclaims Isma'ili authorship of the work and instead attributes the treatises to the 'Alids." (Amusingly, V. A. Ivanov attributes sponsorship of the work to the 'Alids' enemies, the Fatimids, instead, in his A Guide to Ismaili Literature, London 1933) From pg 26-27 of Nasr (1964).
- From pg 8 of Tibawi: "There is sufficient evidence in the tracts themselves to prove Isma'ili sympathies. Indeed, such sympathies have long been pointed out by Muslim authors, medieval and modern, who tried to turn sympathy into actual relationship. However, the balance of evidence tends to show that such relationship was a later development. There is as yet no proof that the formation of Ikhwan as-Safa and the publication of their Rasa'il was an Isma'ili movement, or even a movement concerted with any of the contemporary agitation of the Shi'a." From page 9: "A glaring example of the Ikhwan's independence is their advocacy of the principle that the office of imam need not be hereditary, for they argue that if the desired good qualities are not found in one single person but scattered among a group, then the group and not the individual should be 'the lord of the time and the imam. More surprising still is the denouncement of the belief in a concealed imam as painful to those who hold it and the discredit of the significance of 'number seven' and those who believe in it as contrary to the Ikhwan's creed."
- Compare this extract from one of the later rasa'il Netton provides on pg 102 of his Muslim Neoplatonists: "Know, O Brother, that if these qualities are united simultaneously in one human being, during one of the cycles of astral conjunctions, then that person is the Delegate (al-Mab'uth) and the Master of the Age (Sahib al-Zaman) and the Imam for the people as long as he lives, If he fulfills his mission and accomplishes his allotted task, advises the community and records the revelation, codifies its interpretation and consolidates the holy law, clarifies its method and implements the traditional procedures and welds the community into one; if he does all that and then dies and passes away, those qualities will remain in the community as its heritage. If those qualities, or most of them, are united in one in his community, then he is the man suited to be his successor in his community after his death. But if it does not happen that those qualities are united in one man, but are scattered among all its members, and they speak with one voice and their hearts are united in love for each other, and they cooperate in supporting the faith, preserving the law and implementing the sunna, and bearing the community along the path of religion, then their dynasty will endure in this world and the outcome will be happy for them in the next."
- "No one system satisfied these Brethren. They were too well acquainted with other creeds, and too well trained in the logical use of thought, to accept the common orthodox Islam which had contented the desert Arabs. Yet all other creeds and systems equally appeared open to doubt or refutation. In this confusion they found their satisfaction in an eclectic theory. All these conflicting views, they said, must be only different ways of looking at the same thing..." or "These fragments of truth were to be found in every system of faith and every method of philosophy; if men failed to detect them, the fault lay in their own imperfect intelligence - it was only the skill to read between the lines that was wanted to build up a harmonious whole out of the fragments of truth scattered about in sacred books and the writings of wise men and the mystic doctrines of saints." Stanley Lane-Poole (1883), pgs. 189, 190.
- "The world in relation to Allah is like the word in relation to him who speaks it, like light, or heat or numbers to the lantern, sun, hearth or the number One. The word, light, heat and number exist by their respective sources, but without the sources could neither exist nor persist in being. The existence of the world is thus determined by that of Allah..." Nasr (1964), pg 54-55 (based on "Dieterici, Die Lehre von der Weltseele, R., III, 319.")
- "But in spite of the anthropomorphic image of a Creator sitting on his Throne and looking down on his creation, the thought of the Sincere Brethren repeatedly breaks through the structures of traditional Islamic theology- a fact the numerous Qur'anic quotations (sometimes quite unrelated to the subject under discussion) barely disguise...." van Reijn (1945), pg vii
- "Isma'ilism developed a complex and rich theosophy which owed a great deal to Neoplatonism. In the 9th century, Greek-to-Arabic translations proliferated, first by the intermediary of Syriac then directly. The version of Plotinus' Enneads possessed by Muslims was modified with changes and paraphrases; it was wrongly attributed to Aristotle and called Theologia of Aristotle, since Plotinus (Flutinus) remained mostly unknown to the Muslims by name. This latter work played a significant role in the development of Isma‘ilism." From the article at the Internet Encyclopedia of Philosophy
- pg 234-235 of vol. 3, Rasa'il Ikhwan al-Safa', 4 volumes (Beirut, Dar Sadir, 1957)
- volume 4, pg 685-688 of the 1998 edition of The Routledge Encyclopedia of Philosophy; ed. Edward Craig, ISBN 0-415-18709-5
- pg 41 of vol 1, Rasa'il Ikhwan al-Safa', 4 volumes (Beirut, Dar Sadir, 1957)
- from page 52 (whose translation is based on "Dieterici, Die Lehre von der Weltseele, p. 15. R., II 4f") of Nasr (1964).
- Nasr (1992) p71: Der Darwinisimuseim X and XI Jarhhundert (Leipzig, 1878)
- See Nasr (1992) p72 wherein the text has been quoted from Carra
- Iqbal, Muzaffar Islam and Science (Great Britain: MPG Books Ltd, 1988) 117
- Muhammad Hamidullah and Afzal Iqbal (1993), The Emergence of Islam: Lectures on the Development of Islamic World-view, Intellectual Tradition and Polity, p. 143-144. Islamic Research Institute, Islamabad.
- Zirkle, Conway (April 25, 1941). "Natural Selection before the 'Origin of Species'". Proceedings of the American Philosophical Society.
- Hamori, Andras (1971), "An Allegory from the Arabian Nights: The City of Brass", Bulletin of the School of Oriental and African Studies, Cambridge University Press, 34 (1): 9–19 , doi:10.1017/S0041977X00141540
- 345, Hamdani
- Die Philosophie der Araber im zehnten Jahrhundert, F. Dieterici, published in Berlin and Leipzig between 1865 and 1872; bibliographic information courtesy of The Epistles of the Sincere Brethren, by Eric Van Reijn, 1945, Minerva Press, ISBN 1-85863-418-0
- Such as L. E. Goodman's The Case of the Animals Versus Man Before the King of The Jinn, in Boston 1978
- van Reijn (1945) - The epistle on music of the Ikhwan al-Safa, Amnon Shiloah. Published by Tel-Aviv University, 1978
- van Reijn (1995)
- Guillaume de Vaulx d’Arcy, « Bulletin critique ‒ The Epistle of the Brethren in Purity by the Institute of Ismaili Studies: when the edition of a book can be its destruction », MIDEO, 2019, vol. 34, p. 253‑330.
- Lane-Poole, Stanley (1966) , Studies in a Mosque (1st ed.), Beirut (1966): Khayat Book & Publishing Company S.A.LCS1 maint: location (link); based on Dieterici's outline and translations.
- Nasr, Seyyed Hossein (1964), An Introduction to Islamic Cosmological Doctrines: Conceptions of nature and methods used for its study by the Ihwan Al-Safa, Al-Biruni, and Ibn Sina, Boston, Massachusetts: Belknap Press of Harvard University Press, LCCN 64-13430
- Van Reijn, Eric (1995), The Epistles of the Sincere Brethren: an annotated translation of Epistles 43-47, 1 (1st ed.), Minerva Press, ISBN 1-85863-418-0; a partial translation
- Netton, Ian Richard (1991), Muslim Neoplatonists: An Introduction to the Thought of the Brethren of Purity, 1 (1st ed.), Edinburgh, England: Edinburgh University Press, ISBN 0-7486-0251-8
- Ivanov, Valdimir Alekseevich (1946), The Alleged Founder of Ismailism., The Ismaili Society series,; no. 1; Variation: Ismaili Society, Bombay.; Ismaili Society series ;; no. 1., Bombay, Pub. for the Ismaili Society by Thacker, p. 197, LCCN 48-3517, OCLC: 385503
- Ikhwan as-Safa and their Rasa'il: A Critical Review of a Century and a Half of Research, by A. L. Tibawi, published in volume 2 of The Islamic Quarterly in 1955
- Rasa'il Ikhwan al-Safa', 4, Beirut: Dar Sadir
- Johnson-Davies, Denys (1994), The Island of Animals / Khemir, Sabiha, ; (Illustrator - Ill.), Austin: University of Texas Press, p. 76, ISBN 0-292-74035-2
- "Notices of some copies of the Arabic work entitled "Rasàyil Ikhwàm al-cafâ"", written by Aloys Sprenger, originally published by the Journal of the Asiatic Society of Bengal (in Calcutta) in 1848 
- "Abū Ḥayyan Al-Tawḥīdī and The Brethren of Purity", Abbas Hamdani. International Journal of Middle East Studies, 9 (1978), 345-353
- (in French) La philosophie des Ihwan al-Safa' ("The philosophy of the Brethren of Purity"), Yves Marquet, 1975. Published in Algiers by the Société Nationale d'Édition et de Diffusion
- Epistles of the Brethren of Purity. The Ikhwan al-Safa' and their Rasa'il, ed. Nader El-Bizri (Oxford: Oxford University Press, 2008).
- Article at Encyclopædia Britannica
- "Ikhwan al-Safa'". Internet Encyclopedia of Philosophy.
- Ikhwān al-Safā’[permanent dead link] - (general encyclopedia-style article)
- The Rasail Ikhwan as-Safa
- "Ikhwan al-Safa by Omar A. Farrukh" from A History of Muslim Philosophy 
- Review of Yves Marquet's La philosophie des Ihwan al-Safa': de Dieu a l'homme by F. W. Zimmermann
- "The Classification of the Sciences according to the Rasa'il Ikhwan al-Safa'" by Godefroid de Callataÿ
- The Institute of Ismaili Studies article on the Brethren, by Nader El-Bizri
- The Institute of Ismaili Studies gallery of images of manuscripts of the Rasa’il of the Ikhwan al-Safa’
- "Beastly Colloquies: Of Plagiarism and Pluralism in Two Medieval Disputations Between Animals and Men" -(by Lourdes María Alvarez; a discussion of the animal fables and later imitators; PDF file)
- "Pages of Medieval Mideastern History" - (by Eloise Hart; covers various small scholarly groups influential in the Arabic world)
- "Ikhwanus Safa: A Rational and Liberal Approach to Islam" - (by Asghar Ali Engineer)
- "Mark Swaney on the History of Magic Squares" -(includes a discussion of magic squares and the Encyclopedia)