|The Canon of Medicine|
|The Book of Healing|
|Hayy ibn Yaqdhan|
|Criticism of Avicennian philosophy|
Avicennism (Persian: فلسفه سینایی) is a school of early Persian Islamic philosophy which began during the middle of the Islamic Golden Age. The school was founded by Avicenna (Ibn Sina), an 11th-century Persian philosopher who attempted to redefine the course of early Islamic philosophy and channel it into new directions. His metaphysical system is built on ingredients and conceptual building blocks which are largely Aristotelian and Neoplatonic, but the final structure is something other than the sum of its parts. For example, while he accepted Neoplatonic emanationist cosmology and the "Amonnian" synthesis of later Aristotelian commentators, he rejected Neoplatonic epistemology and the theory of the pre-existent soul. His metaphysics also owes much to Islamic legal theory and Kalam on meaning, signification and being.
This philosophy has recognized the compatibility of the metaphysics of contingency, by which Islamic theologians have tried to rationalize the Islamic idea of creation, and the metaphysics of necessity, in which Aristotelians have defended the idea that the goal of philosophy and science is as to understanding why and how things must be as they are. The key to this philosophy is conceptualization of the world as contingent in itself but necessary with references to its causes, leading back to ultimately to the First Cause. The main innovations in this philosophy are the definite distinction of essence from existence and its relation to the cosmological proof he devised, the ontological argument for the existence of God from the metaphysics of contingency and necessity, his idea about knowledge and "individuality of the disembodied soul" and his "Floating Man" thought experiment.
Due to his successful reconciliation between Aristotelianism and Neoplatonism along with Islamic theology, Avicennism eventually became the leading school of Islamic philosophy by the 12th century and had become a central authority on philosophy by then. In the 13th century, Avicennism was revived by the efforts of Nasīr al-Dīn al-Tūsī, though the interpretation of this Avicennism was based on the ideas of Suhrawardi (founder of Illuminationist philosophy) and Ibn Arabi, and differed from the rationalist Avicennism known in Europe. In the 16th century, Mulla Sadra innovated a new philosophical system, known as Transcendent theosophy, which combined the vision of Sufi metaphysics and the rationalistic Peripatetic approach of Avicenna.
Although the Avicennian school of thought was criticized by theologians such as al-Ghazali, philosophers such as Averroes, and by Sufis such as Rumi and Attar, Avicenna's writings spread like fire and continued until today to form the basis of philosophical education in the Islamic world. For to the extent that the post-Averroistic tradition remained philosophical, especially in the eastern Islamic lands, it moved in the directions charted for it by Avicenna in the investigation of both theoretical and practical sciences. Most of the later Muslim philosophers, theologians and mystics who tried to harmonize philosophy and theology, like Nasir al-Din Tusi, or philosophy and mysticism, like Suhrawardi, and later on, philosophy and theology and mysticism, like Mulla Sadra, also made use of Avicennan methodology and arguments.
Avicenna, the founder of Avicennism, (b. Bukhara 980, d. Hamadan 1037) was a Persian Muslim polymath and the foremost physician and Islamic philosopher of his time. He was also an astronomer, chemist, Hafiz, logician, mathematician, physicist, poet, psychologist, scientist, Sheikh, soldier, statesman and theologian.
Avicenna wrote almost 450 treatises on a wide range of subjects, of which around 240 have survived. In particular, 150 of his surviving treatises concentrate on philosophy and 40 of them concentrate on medicine. His most famous philosophical work is The Book of Healing, a vast philosophical and scientific encyclopaedia. His other prominent philosophical works are Al-Isharat wa-‘l-tanbihat (Remarks and Admonitions), Kitab al-najat (The Book of Deliverance) and Danishnama-i ‘ala’i (The Book of Scientific Knowledge). Avicenna himself writes when introducing his magnum opus, The Book of Healing:
There is nothing in the books of the ancients but we have included in this our book. If something is not found in a place where it is normally found, it would be found in another place where I judge it more fit to be in. I have added to this what I have apprehended with my thought and attained through my reflection, particularly in physics, metaphysics and logic.
Avicenna's legacy in philosophical psychology is primarily embodied in the Kitab al-nafs parts of his Kitab al-shifa' (The Book of Healing) and Kitab al-najat (The Book of Deliverance). These were known in Latin under the title De Anima (treatises "on the soul"). The main thesis of these tracts is represented in his so-called "flying man" argument, which resonates with what was centuries later entailed by Descartes's cogito argument (or what phenomenology designates as a form of an "epoche").
On the other hand, there is the trilogy of the Mystical Recitals or Romances to which Avicenna confided the secret of his personal experience. In so doing, he offers us the rare example of a philosopher taking perfect cognizance of himself and who comes at length to fashion his own symbols. The theme of all three Recitals is the journey towards a mystical Orient, an Orient which is not to be found on our maps, but the idea of which is already present in gnosis. The Recital of Hayy ibn Yaqdhan, means alive son of awake, describes the invitation to travel in the company of the Angel who illuminates. The other one is Recital of the Bird which completes the journey. Finally, Salaman and Absal are the two heroes of the Recital evoked in the last section of the Book of Instructions (Isharat). These are not allegories but symbolic recitals.
Early Islamic philosophy
As Henry Corbin and Oliver Leaman divide Islamic philosophy into several periods, Avicenna belongs to the early or classic period. This period starts with al-Kindi in 9th and finishes with Averroes at the end of 12th century. The death of Ibn Rushd effectively marks the end of a particular discipline of Islamic philosophy usually called the Peripatetic Arabic School, and philosophical activity declined significantly in western Islamic countries, namely in Spain and North Africa, though it persisted for much longer in the Eastern countries, in particular Iran and India which tend to Mystical philosophy and Transcendent Theosophy.
Al-Kindi is often called the first philosopher of the Arabs, and he followed a broadly Neoplatonic approach. One of the earliest of the philosophers in Baghdad was in fact a Christian, Yahya Ibn ‘Adi, and his pupil al-Farabi created much of the agenda for the next four centuries of work. Al-Farabi argued that the works of Aristotle raise important issues for the understanding of the nature of the universe, in particular its origination. Aristotle suggested that the world is eternal, which seems to be in contradiction with the implication in the Qur’an that God created the world out of nothing. Al-Farabi used as his principle of creation the process of emanation, the idea that reality continually flows out of the source of perfection, so that the world was not created at a particular time. A large school of thinkers was strongly influenced by al-Farabi, including Avicenna, and this surely played an important part in making his ideas and methodology so crucial for the following centuries of Islamic philosophy.
Study of Avicennan philosophy
Avicenna's philosophical tenets have become of great interest to critical Western scholarship and to those engaged in the field of Muslim philosophy, in both the West and the East. However, it is still the case that the West only pays attention to a portion of his philosophy known as the Latin Avicennian School. Avicenna's philosophical contributions have been overshadowed by Orientalist scholarship (for example that of Henri Corbin), which has sought to define him as a mystic rather than an Aristotelian philosopher. The so-called حكمت المشرقيه (hikmat-al-mashriqqiyya) remains a source of huge irritation to contemporary Arabic scholars, in particular Reisman, Gutas, Street, and Bertolacci.
The original work, entitled The Easterners (al-mashriqiyun المشرقيون), was probably lost during Avicenna's lifetime; Ibn Tufail (Abubacer) appended it to a romantic philosophical work of his own in the twelfth century, the Hayy ibn Yaqzan, in order to validate his philosophical system, and, by the time that the work was transmitted into the West, appended as it was to a set of "mystical" opusculae and sundry essays, it was firmly accepted as a demonstration of Avicenna's "esoteric" orientation, which he concealed out of necessity from his peers.
Some argue that such interpretations of Avicenna's "true" state of mind ignore the vast corpus of work that he produced, from major treatises to slurs on his enemies and rivals, misrepresent him utterly. It also detracts attention from the fact that Muslim philosophy flourished during the ten centuries after Avicenna's death, emerging from Avicenna's inflammatory pronouncements on all matters within the world, whether physical or metaphysical; the works of the post-Avicennian Baghdadi Peripatetics and anti-Peripatetics, for example, remain to be studied in much greater detail.
Early Islamic philosophy and Islamic metaphysics, imbued as it is with Islamic theology, emphasizes the difference between essence and existence more than Aristotelianism. Whereas existence is the domain of the contingent and the accidental, essence endures within a being beyond the accidental. However, Avicenna's commentaries upon the Metaphysics in particular demonstrate that he was much more clearly aligned with a philosophical comprehension of the metaphysical world rather than one that was grounded in theology. The philosophy of Avicenna, particularly that part relating to metaphysics, owes much to Aristotle and to al-Farabi.
Ontology: Distinction between essence and existence
Avicenna is considered to be the first "philosopher of being" for placing ontology at the heart of philosophy. Influenced by the monotheism of Islam, he considered the study of being to be the heart of Islamic metaphysics. In Islamic philosophy, especially the Avicennan school, the concept of existence appears as a definite and clear concept to a much greater degree than in ancient Greek philosophy. Avicenna also distinguishes between necessity and contingency as a fundamental distinction between Pure Being, which is that of God and is very different from the Aristotelian understanding of being, and the existence of all that is other than Him. God is the Necessary Being (wiijib al-wujúd), while existents are contingent (mumkin al-wujúd) and hence rely in a fundamental way upon the Necessary Being, without which they would be literally nothing.
Following Al-Farabi's lead, Avicenna initiated a full-fledged inquiry into the question of being, in which he distinguished between essence (Mahiat) and existence (Wujud). He argued that the fact of existence can not be inferred from or accounted for by the essence of existing things and that form and matter by themselves cannot interact and originate the movement of the universe or the progressive actualization of existing things. Existence must, therefore, be due to an agent-cause that necessitates, imparts, gives, or adds existence to an essence. To do so, the cause must be an existing thing and coexist with its effect.
The significance of the issue is that there is no issue more central for Islamic philosophy than Wujud (at once being and existence) and its relation to essence. The major ontological distinction made by Avicenna between these two is so central to the whole structure of Islamic philosophy for the past millennium and finally led to division of the philosophers into two groups, one believe in Existentialism or the principiality of existence like Mulla Sadra and the other believe in Essentialism or the principiality of essence like Shahab al-Din Suhrawardi.
Some orientalists (or those particularly influenced by Thomist scholarship) argued that Avicenna was the first to view existence (wujud) as an accident that happens to the essence (mahiyya) and make a real distinction between essence and existence, and was also an early proponent of the concept of essentialism. Avicenna anticipated Frege and Bertrand Russell in "holding that existence is an accident of accidents" and also anticipated Alexius Meinong's "view about nonexistent objects." He also provided early arguments for "a 'necessary being' as cause of all other existents.". However, this aspect of ontology is not the most central to the distinction that Avicenna established between essence and existence. One cannot therefore make the claim that Avicenna was the proponent of the concept of essentialism per se, given that existence (al-wujud) when thought of in terms of necessity would ontologically translate into a notion of the Necessary-Existent-due-to-Itself (wajib al-wujud bi-dhatihi), which is without description or definition, and particularly without quiddity or essence (la mahiyya lahu). Consequently, Avicenna's ontology is 'existentialist' when accounting for being qua existence in terms of necessity (wujub), while it is 'essentialist' in terms of thinking about being qua existence (wujud) in terms of contingency qua possibility (imkan; or mumkin al-wujud: contingent being).
Avicenna was also the first to argue that existence is not a predicate. The idea of "essence precedes existence" is a concept which also dates back to Avicenna and his school of Avicennism, and was further developed by Shahab al-Din Suhrawardi and his Illuminationist philosophy. The opposite idea of "existence precedes essence" was thus developed in the works of Averroes and Mulla Sadra as a reaction to this idea and is a key foundational concept of existentialism.
God as the First Cause and Necessary Existent
- See also: Cosmological argument and Ontological argument
Before Avicenna the discussions among Muslim philosophers were about the unity of God as divine creator and his relationship with the world as creation. The earlier philosophers were affected by the Plotinus' ideas.  The ontological form of cosmological argument is put forwarded by Avicenna which is known as "contingency and necessity argument" (Imakan wa Wujub).
Avicenna found inspiration for this metaphysical view in the works of Al-Farabi, but his innovation is in his account a single and necessary first cause of all existence. Whether this view can be reconciled with Islam, particularly given the question of what role is left for God's will, was to become a subject of considerable controversy within intellectual Islamic discourse. Avicenna's proof for the existence of God was the first ontological argument, which he proposed in the Metaphysics section of The Book of Healing. This was the first attempt at using the method of a priori proof, which utilizes intuition and reason alone. Avicenna's proof of God's existence is unique in that it can be classified as both a cosmological argument and an ontological argument. "It is ontological insofar as ‘necessary existence’ in intellect is the first basis for arguing for a Necessary Existent". The proof is also "cosmological insofar as most of it is taken up with arguing that "contingent existents" cannot stand alone and must end up in a Necessary Existent."  Another argument Avicenna presented for God's existence was the problem of the mind-body dichotomy.
According to Avicenna, the universe consists of a chain of actual beings, each giving existence to the one below it and responsible for the existence of the rest of the chain below. Because an actual infinite is deemed impossible by Avicenna, this chain as a whole must terminate in a being that is wholly simple and one, whose essence is its very existence, and therefore is self-sufficient and not in need of something else to give it existence. Because its existence is not contingent on or necessitated by something else but is necessary and eternal in itself, it satisfies the condition of being the necessitating cause of the entire chain that constitutes the eternal world of contingent existing things. Thus his ontological system rests on the conception of God as the Wajib al-Wujud (necessary existent). There is a gradual multiplication of beings through a timeless emanation from God as a result of his self-knowledge.
This view has a profound impact on the monotheistic concept of creation. Existence is not seen by Avicenna as the work of a capricious deity, but of a divine, self-causing thought process. The movement from this to existence is necessary, and not an act of will per se. The world emanates from God by virtue of his abundant intellect - an immaterial cause as found in the neoplatonic concept of emanation.
In Avicenna's account of creation (largely derived from al-Farabi), from this First Cause proceeds the creation of the material world. The First Cause is transcends the Celestial intelligences that move the spheres. However Avicenna offers his version in response to how multiplicity can have emerged from unity, the First Cause.
The First Intellect, in contemplating the necessity of its existence, gives rise to the Second Intellect. In contemplating its emanation from God, it then gives rise to the First Spirit, which animates the Sphere of Spheres (the universe). In contemplating itself as a self-caused essence (that is, as something that could potentially exist), it gives rise to the matter that fills the universe and forms the Sphere of the Planets (the First Heaven in al-Farabi).
This triple-contemplation establishes the first stages of existence. It continues, giving rise to consequential intellects which create between them two celestial hierarchies: the Superior Hierarchy of Cherubim (Kerubim) and the Inferior Hierarchy, called by Avicenna "Angels of Magnificence". These angels animate the heavens, but are deprived of all sensory perception, but have imagination which allows them to desire the intellect from which they came. Their vain quest to join this intellect causes an eternal movement in heaven. They also cause prophetic visions in humans.
The angels created by each of the next seven Intellects are associated with a different body in the Sphere of the Planets. These are: Saturn, Jupiter, Mars, the Sun, Venus, Mercury and the Moon. The last of these is of particular importance, since its association is with the Angel Gabriel ("The Angel").
This Ninth Intellect occurs at a step so removed from the First Intellect that the emanation that then arises from it explodes into fragments, creating not a further celestial entity, but instead creating human souls, which have the sensory functions lacked by the Angels of Magnificence.
Theory of knowledge and prophecy
According to Avicenna, at birth the incorporeal human soul contains no thought and has merely an empty potentially for thinking. This unqualified potentially for thought which belongs to every member of human being is a deposition inheriting in the incorporeal human soul. The concept of tabula rasa was developed more clearly by Avicenna. Avicenna argued, in the words of Sajjad H. Rizvi, that the "human intellect at birth is rather like a tabula rasa, a pure potentiality that is actualized through education and comes to know" and that knowledge is attained through "empirical familiarity with objects in this world from which one abstracts universal concepts" which is developed through a "syllogistic method of reasoning; observations lead to prepositional statements, which when compounded lead to further abstract concepts." 
For Avicenna, the human intellect has neither the role nor the power to abstract the intelligible from the sensible. Humans are intellectual only potentially, and All knowledge and all recollection are an emanation and an illumination which come from the Angel. Only illumination by the Angel confers upon them the ability to make from this potential a real ability to think. This is the Tenth Intellect, identified with the "active intellect" of Aristotle's De Anima. 
It is dual in structure, practical intellect and contemplative intellect, and its two aspects are known as terrestrial angels. The degree to which minds are illuminated by the Angel varies. Of the four states of the contemplative intellect, the one which corresponds to intimacy with the Angel who is the active Intelligence is called the holy intellect(al-aql al-qudsi). At its height, it attains the privileged status of the spirit of prophecy. Prophets are illuminated to the point that they possess not only rational intellect, but also an imagination and ability which allows them to pass on their superior wisdom to others. Some receive less, but enough to write, teach, pass laws, and contribute to the distribution of knowledge. Others receive enough for their own personal realization, and others still receive less.
On this view, all humanity shares a single agent intellect - a collective consciousness. The final stage of human life, according to Avicenna, is reunion with the emanation of the Angel. Thus, the Angel confers upon those imbued with its intellect the certainty of life after death. For Avicenna, as for the neoplatonists who influenced him, the immortality of the soul is a consequence of its nature, and not a purpose for it to fulfill.
According to Henry Corbin, when it comes to the question of the nous poietikos (intelligentia agens), on which the interpreters of Aristotle have been divided from the beginning, Avicenna, following al-Farabi and Ismaili cosmogony and contrary to Themistius and Thomas Aquinas, opted for an Intelligence which is separate from and extrinsic to the human intellect; yet at the same time he does not identify it with the concept of God, as did Alexander of Aphrodisias and the Augustinians. Al-Farabi and Avicenna regarded this Intelligence as a being in the Pleroma, and as linking man directly to the Pleroma. Hereby these philosophers demonstrated their gnostic originality. On the other hand, they were not content with the Peripatetic notion of the soul as the form of an organic body: this 'information' is only one of the soul's functions, and not even the most important of them. Thus their anthropology is neo-Platonic.
Definition of truth
Avicenna defined truth as:
"What corresponds in the mind to what is outside it."
Avicenna elaborated on his definition of truth in his Metaphysics:
"The truth of a thing is the property of the being of each thing which has been established in it."
In his Quodlibeta, Thomas Aquinas wrote a commentary on Avicenna's definition of truth in his Metaphysics and explained it as follows:
"The truth of each thing, as Avicenna says in his Metaphysica, is nothing else than the property of its being which has been established in it. So that is called true gold which has properly the being of gold and attains to the established determinations of the nature of gold. Now, each thing has properly being in some nature because it stands under the complete form proper to that nature, whereby being and species in that nature is."
Avicenna discussed the topic of logic in Islamic philosophy and Islamic medicine extensively in his works, and developed his own system of logic known as "Avicennian logic". Though only a few works on Avicennian logic were translated during the Latin translations of the 12th century, Avicennian logic had an influence on early medieval European logicians such as Albertus Magnus. However, Aristotelian logic later became more popular in Europe due to the strong influence of Averroism and the many translations of Averroes' commentaries on Aristotelian logic.
Dimitri Gutas and the Stanford Encyclopedia of Philosophy consider the period between the 11th and 14th centuries to be the "Golden Age" of Arabic and Islamic philosophy, initiated by the Persian scholar Al-Ghazali's successful integration of logic into the Madrasah curriculum and the subsequent rise of Persian scholar Avicennism.
One of Avicenna's ideas had a particularly important influence on Western logicians such as William of Ockham. Avicenna's word for a meaning or notion (ma'na), was translated by the scholastic logicians as the Latin intentio. In medieval logic and epistemology, this is a sign in the mind that naturally represents a thing. This was crucial to the development of Ockham's conceptualism. A universal term (e.g. "man") does not signify a thing existing in reality, but rather a sign in the mind (intentio in intellectu) which represents many things in reality. Ockham cites Avicenna's commentary on Metaphysics V in support of this view.
Temporal modal logic
The first criticisms of Aristotelian logic were written by Avicenna, who produced independent treatises on logic rather than commentaries. He criticized the logical school of Baghdad for their devotion to Aristotle at the time. He investigated the theory of definition and classification and the quantification of the predicates of categorical propositions, and developed an original theory on temporal modal syllogism. Its premises included modifiers such as "at all times", "at most times", and "at some time".
Systematic refutations of Greek logic were later written by the Illuminationist school, founded by Shahab al-Din Suhrawardi (1155–1191), who developed the idea of "decisive necessity", which refers to the reduction of all modalities (necessity, possibility, contingency and impossibility) to the single mode of necessity, an important innovation in the history of logical philosophical speculation.
The Arabic theory of temporal modal logic is considered one of the most significant advances in Islamic logic, and was further developed up until the 15th century, with the logical treatise Sharh al-takmil fi'l-mantiq written by Muhammad ibn Fayd Allah ibn Muhammad Amin al-Sharwani being the last major Arabic work on logic.
While Avicenna often relied on deductive reasoning in philosophy, he used a different approach in medicine. Avicenna contributed inventively to the development of inductive logic, which he used to pioneer the idea of a syndrome in the diagnosis of specific diseases. In his medical writings, Avicenna was the first to describe the methods of agreement, difference and concomitant variation which are critical to inductive logic and the scientific method.
Fakhr al-Din al-Razi (b. 1149) criticized Aristotle's "first figure" and formulated an early system of inductive logic, foreshadowing the system of inductive logic developed by John Stuart Mill (1806–1873).
Systematic refutations of Greek logic were written by the Illuminationist school, founded by Shahab al-Din Suhrawardi (1155–1191), who developed the idea of "decisive necessity", which refers to the reduction of all modalities (necessity, possibility, contingency and impossibility) to the single mode of necessity.
Persian scholar Nasir al-Din al-Tusi (1201–1274) wrote the following commentary on Avicenna's theory of absolute propositions:
"What spurred him to this was that in the assertoric syllogistic Aristotle and others sometimes used contradictories of absolute propositions on the assumption that they are absolute; and that was why so many decided that absolutes did contradict absolutes. When Avicenna had shown this to be wrong, he wanted to give a way of construing those examples from Aristotle."
In the 13th century, Ibn al-Nafis (1213–1288) wrote a book on Avicennian logic, which was a commentary of Avicenna's Al-Isharat (The Signs) and Al-Hidayah (The Guidance). In the 14th century, Ibn Khaldun, in his Muqaddimah (1377), wrote the following on how Islamic logic had changed since the 12th century:
"Treatment of [the subject as newly conceived] has become lengthy and wide-ranging—the first to do this was Fakhraddîn ar-Râzî (d. 1210) and, after him, Afdaladdîn al-Khûnajî (d. 1249), on whom Eastern scholars rely even now… The books and ways of the ancients have been abandoned, as though they had never been."
Avicennian epistemology and psychology
Empiricism, tabula rasa, nature versus nurture
One of Avicenna's most influential theories in Muslim psychology and epistemology is his theory of knowledge, in which he developed the concepts of empiricism and tabula rasa, which later gave rise to the nature versus nurture debate in modern philosophy and psychology. He argued that the "human intellect at birth is rather like a tabula rasa, a pure potentiality that is actualized through education and comes to know" and that knowledge is attained through "empirical familiarity with objects in this world from which one abstracts universal concepts" which is developed through a "syllogistic method of reasoning; observations lead to prepositional statements, which when compounded lead to further abstract concepts." He further argued that the intellect itself "possesses levels of development from the material intellect (al-‘aql al-hayulani), that potentiality that can acquire knowledge to the active intellect (al-‘aql al-fa‘il), the state of the human intellect at conjunction with the perfect source of knowledge."
In the 12th century, the Andalusian-Arabian philosopher and novelist Ibn Tufail (known as "Abubacer" or "Ebn Tophail" in the West) first demonstrated Avicenna's theory of tabula rasa as a thought experiment in his Arabic novel, Hayy ibn Yaqdhan, in which he depicted the development of the mind of a feral child "from a tabula rasa to that of an adult, in complete isolation from society" on a desert island. The Latin translation of his work, entitled Philosophus Autodidactus, published by Edward Pococke the Younger in 1671, had an influence on John Locke's formulation of tabula rasa in An Essay Concerning Human Understanding, which went on to become one of the principal sources of empiricism in modern Western philosophy, and influenced many Enlightenment philosophers, such as David Hume and George Berkeley.
Gul A. Russell writes: 
"The principle of associative learning was first introduced by Ibn Sina (Avicenna; d. 1039) in Book VI of the Kitab al-Shifa (there is for example, no Artistotelan foundation). It was further developed in a unique narrative (Hayy ibn Uyakzan) by Ibn Tufayl (d. 1185)."
"Ibn Tufayl’s work provides a graphic exposition as well as an explanation of the emergence and development of the mind of a child (initially cast up on a desert island as a baby and fostered by a gazelle), solely by sensory experience, association, and reasoning, without innate ideas. It will be argued that Ibn Tufayl’s explanation is based on his creation of a coherent synthesis out of Avicenna’s psychological theories from three distinct areas."
Neuropsychiatry, psychophysiology, psychosomatic medicine
In The Canon of Medicine, Avicenna noted the close relationship between emotions and the physical condition and felt that music had a definite physical and psychological effect on patients. Of the many mental disorders that he described in the Qanun, one is of unusual interest: love sickness. Avicenna is reputed to have diagnosed this condition in a Prince in Jurjan who lay sick and whose malady had baffled local doctors. Avicenna noted a fluttering in the Prince's pulse when the address and name of his beloved were mentioned. The great doctor had a simple remedy: unite the sufferer with the beloved.
Avicenna was the pioneer of neuropsychiatry. He first described numerous neuropsychiatric conditions, including hallucination, insomnia, mania, nightmare, melancholia, dementia, epilepsy, paralysis, stroke, vertigo and tremor.
Avicenna was also a pioneer in psychophysiology and psychosomatic medicine, and the firs to recognize 'physiological psychology' in the treatment of illnesses involving emotions, and developed a system for associating changes in the pulse rate with inner feelings, which is seen as an anticipation of the word association test attributed to Carl Jung. Avicenna identified love sickness when he was treating a very ill patient by "feeling the patient's pulse and reciting aloud to him the names of provinces, districts, towns, streets, and people." He noticed how the patient's pulse increased when certain names were mentioned, from which Avicenna deduced that the patient was in love with a girl whose home Avicenna was "able to locate by the digital examination." Avicenna advised the patient to marry the girl he was in love with, and the patient soon recovered from his illness after his marriage.
Thought experiments on self-consciousness
- "Floating Man" thought experiment
While he was imprisoned in the castle of Fardajan near Hamadhan, Avicenna described the earliest known thought experiment, now famously known as the "Floating Man" thought experiment, to demonstrate human self-awareness and the substantiality of the soul. He referred to the living human intelligence, particularly the active intellect, which he believed to be the hypostasis by which God communicates truth to the human mind and imparts order and intelligibility to nature. His "Floating Man" thought experiment tells its readers to imagine themselves in the air, isolated from all sensations, which includes no sensory contact with even their own bodies. He argues that, in this scenario, one would still have self-consciousness. He thus concludes that the idea of the self is not logically dependent on any physical thing, and that the soul should not be seen in relative terms, but as a primary given, a substance. This idea was in contrast with Muslim theologians including Mu'tazili and Ash'ari ones. Avicenna summarized his thought experiment as follows:
"Most people and many of the speculative theologians have thought that the human being is this body and that everyone refers to it when saying 'I'. This is a false belief, as we shall show."
"The one among us must imagine himself as though he is created all at once and created perfect, but that his sight has been veiled from observing external things, and that he is created falling in the air or the void in a manner where he would not encounter air resistance, requiring him to feel, and that his limbs are separated from each other so that they neither meet nor touch. He must then reflect as to whether he will affirm the existence of his self."
"He will not doubt his affirming his self existing, but with this he will not affirm any limb from among his organs, no internal organ, whether heart or brain and no external thing. Rather, he would be affirming his self without affirming it for length, breadth, and depth."
"Hence the one who affirms has a means to be alerted to the existence of his soul as something other than the body - indeed, other than body - and to his being directly acquainted with [this existence] and aware of it."
Later Muslim philosophers and theologians such as Suhrawardi and Nasīr al-Dīn al-Tūsī attempted to further develop this idea. This argument was then later refined and simplified by René Descartes in epistemic terms when he stated: "I can abstract from the supposition of all external things, but not from the supposition of my own consciousness." There's another viewpoint that Descartes's quotation is a misunderstanding when he said "I think, therefore I am." On the basis of Avicenna's discussion, a human knows himself without any internal or external effect and before any thought and if somebody tries to prove himself on the basis of an effect like his own consciousness, then he is just misleading himself.
- "Flying Man" thought experiment
Avicenna also described another similar "Flying Man" thought experiment, which asks the question: "Can the soul be aware of its existence without the body?" Avicenna then responded with the following thought experiment:
"Imagine a man flying in a void. His organs would not register any sensation, and perhaps he would not feel like a three dimensional being. But he would be aware of not experiencing his body, which means that the soul is a spiritual reality."
This experiment was well-known in medieval Europe and had an influence on Christian philosophers such as Saint Bonaventure and Albertus Magnus.
In optics, Ibn Sina posited that the speed of light is finite, as he "observed that if the perception of light is due to the emission of some sort of particles by a luminous source, the speed of light must be finite." He also provided a sophisticated explanation for the rainbow phenomenon. Carl Benjamin Boyer described Ibn Sīnā's theory on the rainbow as follows:
"Independent observation had demonstrated to him that the bow is not formed in the dark cloud but rather in the very thin mist lying between the cloud and the sun or observer. The cloud, he thought, serves simply as the background of this thin substance, much as a quicksilver lining is placed upon the rear surface of the glass in a mirror. Ibn Sīnā would change the place not only of the bow, but also of the color formation, holding the iridescence to be merely a subjective sensation in the eye."
In thermodynamics, a 1253 Latin text entitled Speculum Tripartitum stated the following regarding Avicenna's theory on heat:
Avicenna says in his book of heaven and earth, that heat is generated from motion in external things.
Theory of impetus
- See also: Theory of impetus
In mechanics, Ibn Sīnā, in The Book of Healing, developed an elaborate theory of motion, in which he made a distinction between the inclination and force of a projectile, and concluded that motion was a result of an inclination (mayl) transferred to the projectile by the thrower, and that projectile motion in a vacuum would not cease. This was the first alternative to the Aristotelian theory. In the Avicennan theory of motion, the violent inclination he conceived was non-self-consuming, a permanent force whose effect was dissipated only as a result of external agents such as air resistance, making him "the first to conceive such a permanent type of impressed virtue for non-natural motion." Such a self-motion (mayl) is "almost the opposite of the Aristotelian conception of violent motion of the projectile type, and it is rather reminiscent of the principle of inertia, i.e., Newton's first law of motion." His theory of mayl also attempted to provide a quantitive relation between the weight and velocity of a moving body, resembling the concept of momentum. for which he is considered a pioneer of the concept of momentum. His theory of motion later formed the basis of Jean Buridan's theory of impetus and exerted an influence on the work of Galileo Galilei.
In the 14th century, Jean Buridan rejected the Hipparchan-Philoponan (H-P) notion that the motive force, which he named impetus, dissipated spontaneously, and adopted the Avicennan theory of impetus in which (i) it is only corrupted by the resistances of the medium and of gravity in the case of anti-gravitational motion, but would otherwise be permanently conserved in the absence of any resistances to motion, and in which (ii) gravity is also a downward projector and creator of downward impetus, unlike in the radically different Hipparchan-Philoponan theory in which gravity neither creates not destroys impetus. The assimilation of the role of gravity in natural motion to the role of a projector that creates impetus just as it is created by a thrower in anti-gravitational violent motion was explicitly stated by Buridan's pupil Dominicus de Clavasio in his 1357 De Caelo, as follows:
- "When something moves a stone by violence, in addition to imposing on it an actual force, it impresses in it a certain impetus. In the same way gravity not only gives motion itself to a moving body, but also gives it a motive power and an impetus, ...".
Buridan's position was that a moving object would only be arrested by the resistance of the air and the weight of the body which would oppose its impetus.
- The tunnel experiment and oscillatory motion
The Avicennan-Buridan (A-B) self-conserving impetus theory developed one of the most important thought-experiments in the history of science, namely the so-called 'tunnel-experiment', so important because it brought oscillatory and pendulum motion within the pale of dynamical analysis and understanding in the science of motion for the very first time and thereby also established one of the important principles of classical mechanics. The pendulum was to play a crucially important role in the development of mechanics in the 17th century, and so more generally was the axiomatic principle of Galilean, Huygenian and Leibnizian dynamics to which the tunnel experiment also gave rise, namely that a body rises to the same height from which it has fallen, a principle of gravitational potential energy. As Galileo expressed this fundamental principle of his dynamics in his 1632 Dialogo:
"The heavy falling body acquires sufficient impetus [in falling from a given height] to carry it back to an equal height." 
This imaginary experiment predicted that a canonball dropped down a tunnel going straight through the centre of the Earth and out the other side would go past the centre and rise on the opposite surface to the same height from which it had first fallen on the other side, driven upwards past the centre by the gravitationally created impetus it had continually accumulated in falling downwards to the centre. This impetus would require a violent motion correspondingly rising to the same height past the centre for the now opposing force of gravity to destroy it all in the same distance which it had previously required to create it, and whereupon at this turning point the ball would then descend again and oscillate back and forth between the two opposing surfaces about the centre ad infinitum in principle. Thus the tunnel experiment provided the first dynamical model of oscillatory motion, albeit a purely imaginary one in the first instance, and specifically in terms of A-B impetus dynamics.
Whereas the orthodox Aristotelians could only see pendulum motion as a dynamical anomaly, as inexplicably somehow 'falling to rest with difficulty' as the American irrationalist historian and philosopher of science Tom Kuhn put it in his 1962 The Structure of Scientific Revolutions, on the A-B impetus theory's novel analysis it was not falling with any dynamical difficulty at all in principle, but was rather falling in repeated and potentially endless cycles of alternating downward gravitationally natural motion and upward gravitationally violent motion. Hence, for example, Galileo was eventually to appeal to pendulum motion to demonstrate that the speed of gravitational free-fall is the same for all unequal weights precisely by virtue of dynamically modelling pendulum motion in this manner as a case of cyclically repeated gravitational free-fall along the horizontal in principle. In Kuhnian terms, this A-B impetus dynamics model of pendulum motion was 'a gestalt-switch induced by lateral thinking'.
In fact the tunnel experiment, and hence pendulum motion, was an imaginary crucial experiment in favour of A-B impetus dynamics against both orthodox Aristotelian dynamics without any auxiliary impetus theory, and also against Aristotelian dynamics with its H-P variant. For according to the latter two theories the bob cannot possibly pass beyond the normal. In orthodox Aristotelian dynamics there is no force to carry the bob upwards beyond the centre in violent motion against its own gravity that carries it to the centre, where it stops. And when conjoined with the H-P auxiliary theory, in the case where the canonball is released from rest, again there is no such force because either all the initial upward force of impetus originally impressed within it to hold it in static dynamical equilibrium has been exhausted, or else if any remained it would be acting in the opposite direction and combine with gravity to prevent motion through and beyond the centre. Nor were the canonball to be positively hurled downwards, and thus with a downward initial impetus, could it possibly result in an oscillatory motion. For although it could then possibly pass beyond the centre, it could never return to pass through it and rise back up again. For dynamically in this case although it would be logically possible for it to pass beyond the centre if when it reached it some of the constantly decaying downward impetus remained and still sufficiently much to be stronger than gravity to push it beyond the centre and upwards again, nevertheless when it eventually then became weaker than gravity, whereupon the ball would then be pulled back towards the centre by its gravity, it could not then pass beyond the centre to rise up again, because it would have no force directed against gravity to overcome it. For any possibly remaining impetus would be directed 'downwards' towards the centre, that is, in the same direction in which it was originally created.
Thus pendulum motion was dynamically impossible for both orthodox Aristotelian dynamics and also for H-P impetus dynamics on this 'tunnel model' analogical reasoning. But it was predicted by the A-B impetus theory's tunnel prediction precisely because that theory posited that a continually accumulating downwards force of impetus directed towards the centre is acquired in natural motion, sufficient to then carry it upwards beyond the centre against gravity, and rather than only having an initially upwards force of impetus away from the centre as in the H-P theory of natural motion. So the tunnel experiment constituted a crucial experiment between three alternative theories of natural motion.
On this analysis then A-B impetus dynamics was to be preferred if the Aristotelian science of motion was to incorporate a dynamical explanation of pendulum motion. And indeed it was also to be preferred more generally if it was to explain other oscillatory motions, such as the to and fro vibrations around the normal of musical strings in tension, such as those of a zither, lute or guitar. For here the analogy made with the gravitational tunnel experiment was that the tension in the string pulling it towards the normal played the role of gravity, and thus when plucked i.e. pulled away from the normal and then released, this was the equivalent of pulling the canonball to the Earth's surface and then releasing it. Thus the musical string vibrated in a continual cycle of the alternating creation of impetus towards the normal and its destruction after passing through the normal until this process starts again with the creation of fresh 'downward' impetus once all the 'upward' impetus has been destroyed.
Philosophy of education
In the medieval Islamic world, an elementary school was known as a maktab, which dates back to at least the 10th century. Like madrasahs (which referred to higher education), a maktab was often attached to a mosque. In the 11th century, Ibn Sina, in one of his books, wrote a chapter dealing with the maktab entitled "The Role of the Teacher in the Training and Upbringing of Children", as a guide to teachers working at maktab schools. He wrote that children can learn better if taught in classes instead of individual tuition from private tutors, and he gave a number of reasons for why this is the case, citing the value of competition and emulation among pupils as well as the usefulness of group discussions and debates. Ibn Sina described the curriculum of a maktab school in some detail, describing the curricula for two stages of education in a maktab school.
Ibn Sina wrote that children should be sent to a maktab school from the age of 6 and be taught primary education until they reach the age of 14. During which time, he wrote that they should be taught the Qur'an, Islamic metaphysics, language, literature, Islamic ethics, and manual skills (which could refer to a variety of practical skills).
Ibn Sina refers to the secondary education stage of maktab schooling as the period of specialization, when pupils should begin to acquire manual skills, regardless of their social status. He writes that children after the age of 14 should be given a choice to choose and specialize in subjects they have an interest in, whether it was reading, manual skills, literature, preaching, medicine, geometry, trade and commerce, craftsmanship, or any other subject or profession they would be interested in pursuing for a future career. He wrote that this was a transitional stage and that there needs to be flexibility regarding the age in which pupils graduage, as the student's emotional development and chosen subjects need to be taken into account.
Philosophy of science
In the Al-Burhan (On Demonstration) section of the The Book of Healing, Avicenna discussed the philosophy of science and described an early scientific method of inquiry. He discusses Aristotle's Posterior Analytics and significantly diverged from it on several points. Avicenna discussed the issue of a proper methodology for scientific inquiry and the question of "How does one acquire the first principles of a science?" He asked how a scientist would arrive at "the initial axioms or hypotheses of a deductive science without inferring them from some more basic premises?" He explains that the ideal situation is when one grasps that a "relation holds between the terms, which would allow for absolute, universal certainty." Avicenna then adds two further methods for arriving at the first principles: the ancient Aristotelian method of induction (istiqra), and the method of examination and experimentation (tajriba). Avicenna criticized Aristotelian induction, arguing that "it does not lead to the absolute, universal, and certain premises that it purports to provide." In its place, he develops "a method of experimentation as a means for scientific inquiry."
In The Canon of Medicine, Avicenna was the first to describe the methods of agreement, difference and concomitant variation which are critical to inductive logic and the scientific method. However, unlike his contemporary Abū Rayhān al-Bīrūnī who developed scientific methods where "universals came out of practical, experimental work" and "theories are formulated after discoveries", Avicenna developed a scientific method where "general and universal questions came first and led to experimental work."
Avicenna and Abū Rayhān al-Bīrūnī, who are both regarded as two of the greatest polymaths in Persian history, engaged in a written debate, with al-Biruni mostly criticizing Aristotelian natural philosophy and the Peripatetic school, while Avicenna and his student Ahmad ibn 'Ali al-Ma'sumi respond to al-Biruni's criticisms in writing. Al-Biruni began by asking Avicenna eighteen questions, ten of which were criticisms of Aristotle's On the Heavens, with his first question criticizing Aristotle's reasons for denying the existence of levity or gravity in the celestial spheres and the Aristotelian notion of circular motion being an innate property of the heavenly bodies.
Biruni's second question criticizes Aristotle's over-reliance on more ancient views concerning the heavens, while the third criticizes the Aristotelian view that space has only six directions. The fourth question deals with the continuity and discontinuity of physical bodies, while the fifth criticizes the Peripatetic school's denial of the possibility of there existing another world completely different from the world known to them. In his sixth question, Biruni rejects Aristotle's view on the celestial spheres having circular orbits rather than elliptic orbits. In his seventh question, he rejects Aristotle's notion that the motion of the heavens begins from the right side and from the east, while his eighth question concerns Aristotle's view on the fire element being spherical. The ninth question concerns the movement of heat, and the tenth question concerns the transformation of elements. The eleventh question concerns the burning of bodies by radiation reflecting off a flask filled with water, and the twelfth concerns the natural tendency of the classical elements in their upward and downward movements. The thirteenth question deals with vision, while the fourteenth concerns habitation on different parts of Earth. His fifteenth question asks how two opposite squares in a square divided into four can be tangential, while the sixteenth question concerns vacuum. His seventeenth question asks "if things expand upon heating and contract upon cooling, why does a flask filled with water break when water freezes in it?" His eighteenth and final question concerns the observable phenomenon of ice floating on water.
After Avicenna responded to the questions, Biruni was unsatisfied with some of the answers and wrote back commenting on them, after which Avicenna's student Ahmad ibn 'Ali al-Ma'sumi wrote back on behalf of Avicenna.
Avicenna was a devout Muslim and sought to reconcile rational philosophy with Islamic theology (Kalam). His aim was to prove the existence of God and his creation of the world scientifically and through reason and logic.
Avicenna wrote a number of treatises dealing with Islamic theology. These included treatises on the Islamic prophets, who he viewed as "inspired philosophers", and on various scientific and philosophical interpretations of the Qur'an, such as how Quranic cosmology corresponds to his own philosophical system. He attempted to use philosophy in order to prove the realities established by the Islamic prophetic tradition.
Avicenna's investigation into the natural sciences was inspired by his quest to discover the signs (a’yat) of Allah and thus arrive at a better understanding and appreciation of God’s magnificence. He wrote:
"There is a natural hierarchy of knowledge from the physics of matter to the metaphysics of cosmological speculation, yet all knowledge terminates in the Divine. All phenomena are creations of Allah, His theophanies, and nature is a vast unity to be studied by believers as the visible sign of the Godhead. Nature is like an oasis in the bleak solitude of the desert; the tiny blades of grass as well as the most magnificent flowers bespeak of the gardener's loving hand. All nature is such a garden, the cosmic garden of God. Its study is a sacred act."
Avicenna memorized the Qur'an by the age of seven, and as an adult, he wrote five treatises commenting on suras from the Qur'an. One of these texts included the Proof of Prophecies, in which he comments on several Quranic verses and holds the Qur'an in high esteem. Avicenna argued that the Islamic prophets should be considered higher than philosophers, and in his Autobiography, he considered both religion and philosophy as necessary parts of the entire truth.
Avicennism in Islamic philosophy
Avicenna's immediate followers were of the highest standing. There was, first and foremost, the faithful Abu Ubayd al-Juzjani, who wrote a Persian version and commentary on the Hayy ibn Yaqdhan; Ibn Tufail (Abubacer) wrote a philosophical novel, also entitled Hayy ibn Yaqzan; Husayn ibn Zayla of Isfahan, who wrote a commentary on it in Arabic; and Bahmanyar, a Zoroastrian whose important work remains unedited.
However Avicennism affected the critics too. Just two generations after Avicenna, al-Ghazali testifies to the fact that no serious Muslim thinker could ignore the claim of philosophy as a way to the highest and most comprehensive knowledge available to man and as a way to the Truth. He also testifies to the fact that philosophy for all practical purposes meant Avicenna's philosophy. When he tried to present the intentions of the philosophers, he wrote a summary of Avicenna's philosophy. And when he tried to show the incoherence of the philosophers, he wrote a refutation of Avicennism. Similarly, when Al-Shahrastani came to give an account of the doctrines of “the philosophers of Islam” as distinguished from the doctrines of Greek or Indian philosophers, he simply summarized the doctrines of “the most distinguished ... Avicenna”. His supriority has been so great that several scholars in the 12th century commented on his strong influence at the time:
"People nowadays [believe] that truth is whatever [Ibn Sina] says, that it is inconceivable for him to err, and that whoever contradicts him in anything he says cannot be rational."
Most of the later Muslim theologians and mystics who tried to harmonize philosophy and theology, like Nasir al-Din Tusi, or philosophy and mysticism, like Suhrawardi, and later on, philosophy and theology and mysticism, like Mulla Sadra, also made use of Avicennan methodology and arguments.
Criticism and post-Avicennian philosophy among Muslims
- See also: Early Islamic philosophy, Sufi philosophy, Persian philosophy, Eastern philosophy, and Scholasticism
Avicenna's philosophical doctrine was later criticized by Muslim theologians, Sufis and other Islamic philosophers. These criticisms eventually led to a new philosophy in the 16th century known as Transcendent Theosophy.
Ash'ari theologians, especially al-Ghazali and Fakhr al-Din al-Razi, criticized him due to the contrast of some of his ideas to that of the Qur'an and Hadith. Al-Ghazali, in his famous work The Incoherence of the Philosophers (Tahafat al-Falasafah), criticized Avicenna in three cases: First, qadim, that is the world has no beginning in the past and is not created in time. Second, that God's knowledge includes only classes of beings (universals) and does not extend to individual beings and their circumstances (particulars), and third, bodily resurrection, i.e. after death the souls of humans will never again return into bodies. According to al-Ghazali, in these three cases the teachings of Islam, which are based on revelation, suggest the opposite and thus overrule the unfounded claims of Avicenna.
He accused Avicenna of disbelief in Islam and even argued that it was fard to consider him a Kafir, despite the fact that Avicenna accepted the shortage of his own philosophy in several works, including The Book of Healing, where he confessed that he can not prove bodily resurrection but accepts it on the basis of faith. In the following period, in the wake of Avicenna's Peripatetic philosophy in the 11th and 12th centuries, Ash'ari theology was predominant in the eastern Islamic lands. Of course, as Henry Corbin mentions, Avicennism didn't fade away by such criticisms in the Muslim world, especially in Iran.
Among Muslim philosophers Averroes criticized Avicenna due to his divergence from Aristotle. He rejected the theory of the celestial Souls, and consequently the theory of an imagination which is independent of the corporeal senses. The tide of Averroism was to submerge the effects of Avicennism in Christianity, though quite a different fate awaited it in the East. There Averroism was unknown, and al-Ghazali's critique didn't have great effect.
On the other hand some Sufis such as Rumi and Attar usually criticized rationalistic methodology of Early Islamic philosophy which put reason as a curtain between intellect and truth, which lead to considering the God as the First Cause which couldn't be worshiped. Sufis also have criticized Avicenna on the basis of Sufi metaphysics. For example Farid-al-Din Attar criticized him while describes Tawhid in Conference of the Birds. The basis of the criticism is "Wahdat-ul-Wujood" or Unity of Being which means there is not any true being but God. This idea contradicts with the Avicennan cosmology which considers God as the first cause of all things. According to Sufism there isn't any real cause but God.
Insofar as the opposition between al-Ghazali and philosophers may with truth be defined as the opposition between the philosophy of the heart and pure speculative philosophy, it was one that could be overcome only by something which did not reject either philosophy or the spiritual experience of Sufism, this was the doctrine of al-Suhrawardi. In the eastern part of Muslim lands Shahab al-Din Suhrawardi followed Avicenna's attempts to build an "Oriental philosophy" (Hikmat al-Mashriqia), a project which according to Suhrwardi, could never have been completed because he was ignorant of true Oriental sources such as Persian philosophy. Al-Suhrawardi essentialistic approach led to a new philosophy which is known as the School of Illumination. As Suhrwardi wrote in the beginning of Story of Western Loneliness, he starts the story from where Avicenna ended the story of Hayy ibn Yaqdhan.
In the 13th century, Avicennism was revived by the efforts of Nasir al-Din Tusi, though the interpretation of this Avicennism was based on the ideas of Suhrwardi and Ibn Arabi, and differed from the rationalist Avicennism known in Europe. In the 16th century, Mulla Sadra innovated a new philosophical system which combined the vision of Sufi metaphysics and the rationalistic Peripatetic approach of Avicenna. He also solved some of the major problems in Avicennism such as bodily resurrection.
Avicennism in medieval Europe
In medieval Europe, the main significance of the Latin corpus lies in the interpretation of Avicennism, in particular for regarding his doctrines on the nature of the soul and his existence-essence distinction, along with the debates and censure that they raised in scholastic Europe. This was particularly the case in Paris, where Avicennism was later proscribed in 1210. However, the influence of his psychology and theory of knowledge upon William of Auvergne and Albertus Magnus have been noted. More significant is the impact of his metaphysics upon the work and thought of Thomas Aquinas. Finally the tide of Averroism was to submerge the effects of Avicennism in Christianity.
The Latin followers of Avicenna, known as the "Avicennian left" in Europe, also came close to materialism in the 13th century, according to Ernest Mandel.
- Ibn Sina Academy of Medieval Medicine and Sciences
- The Book of Healing
- Iranian philosophy
- Islamic philosophy
- Early Islamic philosophy
- Sufi philosophy
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- Sajjad H. Rizvi (2006), Avicenna/Ibn Sina (CA. 980-1037), Internet Encyclopedia of Philosophy
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- (Razavi 1997, p. 130)
- نظريه توحيد و راههای اثبات آن تا پيش از ابنسينا غالباً بر محور ارتباط خدا با جهان آفرينش، يعنی وحدت آفريننده جهان از جهت آفرينندگی او، در نظر بوده است. كندی (ج 1، ص 207) در رسالهای كه در پاسخ به علیبن جَهْم نگاشته، خدا را به عنوان مُحدِث جهان، واحد خوانده و برای اثبات اين مطلب، به اقامه استدلال به شيوه مذكور پرداخته است. برای فارابی (1405، ص 102) نيز اساس تبيين و اثبات توحيد، همين رابطه آفرينندگی خدا نسبت به جهان است. برای تبارشناسيِ اين بذلِ توجه فيلسوفان مسلمان به رابطه خدا با جهان در اثبات توحيد، میتوان به استشهاد فارابی (همانجا) به اُثولوجيا اشاره كرد. با توجه به اينكه اُثولوجيا نوشته فلوطين * (متوفی 269 يا 270 ميلادی) است، شايد بتوان يكی از ريشههای اين گرايش فيلسوفان مسلمان را انديشه فلوطين دانست. گر چه فارابی (1982، ص 39؛ همو، 1993، ص 42، 45) بنا بر اين گرايش، در اثبات وحدت خدا از برخی معانی، مانند «اول بودن»، استفاده كرده، لكن بر خلاف فلوطين، رابطه خدا را با جهان همانند رابطه جزء و كل، و نوعی رابطه درونی و حلولی ندانسته، بلكه بر تغاير جوهری و ذاتی خدا با جهان تصريح نموده است. علاوه بر اين، از حيث وجود نيز خدا را وجودی خاص و متمايز و از اين جهت نيز «واحد» دانست Tawhid in the words of Philosophers Encyclopaedia Islamica
- Johnson (1984), pp. 161–171.
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- AVICENNA'S COSMOLOGICAL ARGUMENT FOR GOD'S EXISTENCE
- Davidson (1992) p.82
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- Corbin (1993), p.172
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- Richard F. Washell (1973), "Logic, Language, and Albert the Great", Journal of the History of Ideas 34 (3), p. 445-450 .
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- Kneale p. 229
- Kneale: p. 266; Ockham: Summa Logicae i. 14; Avicenna: Avicennae Opera Venice 1508 f87rb
- History of logic: Arabic logic, Encyclopædia Britannica.
- Dr. Lotfollah Nabavi, Sohrevardi's Theory of Decisive Necessity and kripke's QSS System, Journal of Faculty of Literature and Human Sciences.
- Nicholas Rescher and Arnold vander Nat, "The Arabic Theory of Temporal Modal Syllogistic", in George Fadlo Hourani (1975), Essays on Islamic Philosophy and Science, p. 189-221, State University of New York Press, ISBN 0873952243.
- Lenn Evan Goodman (2003), Islamic Humanism, p. 155, Oxford University Press, ISBN 0195135806.
- Lenn Evan Goodman (1992), Avicenna, p. 33, Routledge, ISBN 041501929X.
- Muhammad Iqbal, The Reconstruction of Religious Thought in Islam, "The Spirit of Muslim Culture" (cf.  and )
- Dr. Abu Shadi Al-Roubi (1982), "Ibn Al-Nafis as a philosopher", Symposium on Ibn al-Nafis, Second International Conference on Islamic Medicine: Islamic Medical Organization, Kuwait (cf. Ibn al-Nafis As a Philosopher, Encyclopedia of Islamic World).
- G. A. Russell (1994), The 'Arabick' Interest of the Natural Philosophers in Seventeenth-Century England, pp. 224-262, Brill Publishers, ISBN 9004094598.
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- Nasr (1996), pp. 315, 1022 and 1023
- پارسانيا حميد (1989) حديث پيمانه
- Nasr (1996), pp. 315 and 1023
- Turgut Özal, The Philosophies of Islam, Greece and the West
- Robert Briffault (1938). The Making of Humanity, p. 191.
- George Sarton, Introduction to the History of Science, Vol. 1, p. 710.
- Carl Benjamin Boyer (1954). "Robert Grosseteste on the Rainbow", Osiris 11, p. 247-258 .
- Gutman, Oliver (1997). "On the Fringes of the Corpus Aristotelicum: the Pseudo-Avicenna Liber Celi Et Mundi". Early Science and Medicine 2 (2): 109–28. Brill Publishers. doi:10.1163/157338297X00087.
- Fernando Espinoza (2005). "An analysis of the historical development of ideas about motion and its implications for teaching", Physics Education 40 (2), p. 141.
- Aydin Sayili (1987), "Ibn Sīnā and Buridan on the Motion of the Projectile", Annals of the New York Academy of Sciences 500 (1): 477–482 : Ibn Sina adopted this idea in its rough outline, but the violent inclination as he conceived it was a non-self-consuming one. It was a permanent force whose effect got dissipated only as a result of external agents such as air resistance. He is apparently the first to conceive such a permanent type of impressed virtue for non-natural motion. [...] Indeed, self-motion of the type conceived by Ibn Sina is almost the opposite of the Aristotelian conception of violent motion of the projectile type, and it is rather reminiscent of the principle of inertia, i.e., Newton's first law of motion.
- Seyyed Hossein Nasr & Mehdi Amin Razavi (1996). The Islamic intellectual tradition in Persia. Routledge, 72. ISBN 0700703144.
- Seyyed Hossein Nasr, "Islamic Conception Of Intellectual Life", in Philip P. Wiener (ed.), Dictionary of the History of Ideas, Vol. 2, p. 65, Charles Scribner's Sons, New York, 1973-1974.
- Seyyed Hossein Nasr & Mehdi Amin Razavi (1996). The Islamic intellectual tradition in Persia. Routledge, 72. ISBN 0700703144.
- A. Sayili (1987), "Ibn Sīnā and Buridan on the Motion of the Projectile", Annals of the New York Academy of Sciences 500 (1), pp. 477–482
- "Jean Buridan: Quaestiones on Aristotle's Physics".
- See p22-3 & p227 Dialogo, Stillman Drake (tr) University of California Press 1953, where the tunnel experiment is discussed. Also see Galileo's Discorsi, p206-8 on p162-4 Drake 1974 where Salviati presents 'experimental proof' of this postulate by pendulum motions.
- For statements of the relationship between pendulum motion and the tunnel prediction, see for example Oresme's discussion in his Treatise on the Heavens and the World translated on p.570 of Clagett's 1959, and Benedetti's discussion on p235 of Drake & Drabkin 1959. For Buridan's discussion of pendulum motion in his Questiones see p.537-8 of Clagett 1959
- See pp117-125 of 1962 edition and pp118-26 of its 1970 second edition.
- See p128-131 of his 1638 Discorsi, translated on p86-90 of Drake's 1974 English edition.
- (1999) The Age of Achievement: Vol 4. Motilal Banarsidass, 33–4. ISBN 8120815963.
- (1999) The Age of Achievement: Vol 4. Motilal Banarsidass, 34–5. ISBN 8120815963.
- McGinnis, Jon (July 2003). "Scientific Methodologies in Medieval Islam". Journal of the History of Philosophy 41 (3): 307–327. doi:10.1353/hph.2003.0033.
- Sardar, Ziauddin (1998). "Islamic Philosophy". Routledge Encyclopedia of Philosophy. Retrieved on 2008-02-03.
- Rafik Berjak and Muzaffar Iqbal, "Ibn Sina--Al-Biruni correspondence", Islam & Science, June 2003.
- Rafik Berjak and Muzaffar Iqbal, "Ibn Sina--Al-Biruni correspondence", Islam & Science, December 2003.
- Rafik Berjak and Muzaffar Iqbal, "Ibn Sina--Al-Biruni correspondence", Islam & Science, Summer 2004.
- Rafik Berjak and Muzaffar Iqbal, "Ibn Sina--Al-Biruni correspondence", Islam & Science, Winter 2004.
- Lenn Evan Goodman (2003), Islamic Humanism, p. 8-9, Oxford University Press, ISBN 0195135806.
- James W. Morris (1992), "The Philosopher-Prophet in Avicenna's Political Philosophy", in C. Butterworth (ed.), The Political Aspects of Islamic PhIlosophy, Chapter 4, Cambridge Harvard University Press, p. 142-188 [159-161].
- Nadarajan, Gunalan (October 2005). "Islamic Automation: A Reading of al-Jazari's The Book of Knowledge of Ingenious Mechanical Devices (1206)" (PDF). Media Art Histories Archive. Retrieved on 2008-09-05.
- Jules Janssens (2004), "Avicenna and the Qur'an: A Survey of his Qur'anic commentaries", MIDEO 25, p. 177-192.
- Corbin (1993), p.174
- Al-Ghazali by Stanford Encyclopedia of Philosophy, First published Tue 14 Aug, 2007
- Keller, Nuh Ha mim (2006), Kalam and Islam
- Nasr, (1996) p.35
- Corbin, (1993) p. 174
- Nasr, (2006) p. 86 and 87
- Corbin (1993), p.153
- Corbin (1993), p.171
- علم تقليدي وبال جان ماست عاريه است و ما نشسته كان ماست علم گفتاري كه آن بيجان بود طالب روي خريداران بود به عقيدهي مولانا، فلسفه و به ويژه بخش مابعدالطبيعهي آن، بارزترين جلوهي علم تقليدي است. چرا كه با افضل معلوم - خداوند متعال - برخوردي مبتني بر بيگانگي و نه الفت اتخاذ كرده است. اينكه مولانا «علت اولي» ناميدن خداوند را سقيم (56) مييابد و از قول خداوند ميگويد كه «چار طبع و علت اولي نيام»، دليل بيزاري مولانا از طرز تلقي فلاسفه از خداوند است. خداوندي كه بارزترين صفت او «علت اولي» بودن باشد، البته نميتواند قبلهي آشنايي و عشقورزي و حاجت خواهي آدمي قرار گيرد. به نظر ميرسد اين مواجههي مبتني بر بيگانگي فلاسفه با خداوند، عمدهترين دليل بيزاري مولانا از اهل فلسفه بوده باشد. اينگونه مواجهه سبب گرديده است كه مولانا بارزترين نمود علم تقليدي را در فلسفه سراغ كند و فلسفه و اهل آن را به نمايندگي تمام علوم تقليدي مورد طعن و تعريض [ http://www.iptra.ir/vdcjuqxheem.html ريشه جدال مولانا با فلسفه چه بود]
- رفت پیش بوعلی آن پیر زن کاغذی زر برد کین بستان ز من شیخ گفتش عهد دارم من که نیز جز ز حق نستانم از کس هیچچیز پیرزن در حال گفت ای بوعلی از کجا آوردی آخر احولی تو درین ره مرد عقد و حل نهای چند بینی غیر اگر احول نهای حکایت پیرزنی که کاغذ زری به بوعلی داد
- Corbin (1993), p. 251
- Corbin (1993), p. 174
- Nasr (2006), p. 87
- The Internet Encyclopedia of Philosophy, Avicenna/Ibn Sina (CA. 980-1037)
- Ernest Mandel (1986), The Place of Marxism in History, "I. The general historical context"
- Corbin, Henry (1993 (original French 1964)). History of Islamic Philosophy, Translated by Liadain Sherrard, Philip Sherrard. London; Kegan Paul International in association with Islamic Publications for The Institute of Ismaili Studies, 167–175. ISBN 0710304161.
- Davidson, Herbert Alan (1992). Alfarabi, Avicenna, and Averroes, on Intellect. Oxford University Press US. ISBN :0195074238.
- Goodman, Lenn Evan (1992). Avicenna. Routledge. ISBN 041501929X.
- Razavi, Mehdi Amin (1997). Suhrawardi and the School of Illumination. Routledge. ISBN 0700704124.
- Nasr, Seyyed Hossein; Oliver Leaman (1996). History of Islamic Philosophy. Routledge. ISBN 0415131596.
- Nasr, Seyyed Hossein (2006). Islamic Philosophy from Its Origin to the Present: Philosophy in the Land of prophecy. SUNY Press. ISBN 0791467996.
- Hakim Syed Zillur Rahman. Resalah Judiya of Ibn Sina (First edition 1971), Literary Research Unit, CCRIH, Aligarh Muslim University, Aligarh; (Second edition 1981) Central Council for Research in Unani Medicine, Govt. of India, New Delhi; (Fourth edition 1999), Central Council for Research in Unani Medicine, Govt. of India, New Delhi.
- Hakim Syed Zillur Rahman (1996). AI-Advia al-Qalbia of Ibn Sina. Publication Division, Aligarh Muslim University, Aligarh.
- Hakim Syed Zillur Rahman. Ilmul Amraz of Ibn Sina(First edition 1969), Tibbi Academy, Delhi (Second edition 1990), (Third edition 1994), Tibbi Academy, Aligarh.
- Nasr, Seyyed Hossein (2007). "Avicenna". Encyclopedia Britannica Online. Retrieved on 2007-11-05.
- "Islam". Encyclopedia Britannica Online. (2007). Retrieved on 2007-11-27.
- Hakim Syed Zillur Rahman (1986). "Qanoon lbn Sina Aur Uskey Shareheen wa Mutarjemeen".. Publication Division, Aligarh Muslim University, Aligarh.
- Special Numbers
- Shaikh al Rais Ibn Sina (Special number) 1958-59, Ed. Hakim Syed Zillur Rahman, Tibbia College Magazine, Aligarh Muslim University, Aligarh, India.
- Ibn Sina (Islamic Philosophy Online)
- Avicenna on the subject and the object of metaphysics with annotated bibliography
- Influence of Arabic and Islamic Philosophy on Judaic Thought by Stanford Encyclopedia of Philosophy