Theory and History of Ontology

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Avicenna (Ibn-Sina) on the Subject and the Object of Metaphysics


"Ibn Sina (Arabic), also known as Avicenna (Latin) and Abu Ali Sina (Persian) was the most original and systematic Muslim philosopher. In this light he is mentioned by two celebrated historians of medieval western philosophy: A. Maurer states, "...his [ibn Sina's] philosophy is a highly personal achievement, ranking among the greatest in the history of philosophy;" and F. Copleston holds, "The greatest Muslim philosopher of the eastern group without doubt is Avicenna or ibn Sina (980-1037), the real creator of a scholastic system in the Islamic world." (1) Y. Mahdavi lists 244 texts attributed to him and G. A. Anawati lists 270. (2) These works envelop a multiplicity of topics such as metaphysics, poetics, animal physiology, minerals, rhetoric, mechanics of solids, Arabic syntax, meteorology, mystical treatises, and a medical treatise, and are translated into more than nineteen languages. The crown of his philosophical corpus is a set of encyclopedic collections of treatises, especially al-Shifa, al-Najàt, al-Isharatwa al-Tanbihàt and the Danish Nameh; each collection contains elaborate philosophical treatises on metaphysics, physics, psychology, and logic. A standard edition of the logical texts of al-Shifa' alone comprises more than one sixteen hundred double size (1600) pages. (3)


Contemporary philosophies of logical syntax of a language distinguish between two types of primitives-one, designative types of sign, the other, rules for transformation, designation, and interpretation, and these distinctions can be applied to ibn Sina's system.

Ibn Sina's two primordial notions of the soul are 'being' (hasti, wujûd) and the modalities [of necessity (wajib), contingency (mumkin) and impossibility (mumtani )]. The notion of being is the core of his system, while the modalities specify the subset of beings that are existents. The notion of 'being' concatenated with 'necessity' point to 'the necessary being;' using the second version of the ontological argument, 'necessary being' results in 'the Necessary Existent.' The notion of 'being' concatenated with 'contingency' has two possible results: (a) if there is a cause for the case in question, then the contingency is an actual existent-for example, in the case of 'being a human,' persons are existents because they have parents; (b) in the case of absence of the cause, the results are non-actual contingencies such as unicorns. 'Impossibility' and 'being' lead to no existent, as illustrated by 'round squares,' and 'the largest number.' The key notions of ibn Sina's system are very clear: 'Being-qua-being' (hasti, wujûd) corresponds to Aristotle's notion of 'being-qua-being' in Metaphysica 1002a 20 (ὂν ἢ ὀν) and E. Moody's reading of Ockham's use of 'ens' in Summa Totius Logicae. (4) It signifies the most determinable concept. 'Non-being' is meaningless. We should note that all mental concepts (actual or not actual) signify a being. For this reason 'being' is different from 'existent'.

'Existent' (mawjûd) signifies actual entities, Aristotle's notion of first substance (πρώτη φιλοσοφία). There are no impossible existents. For ibn Sina there is only one Necessary existent, which is the ultimate cause of generation of other existents. 'Existence' itself is not an existent, but signifies those entities which are neither uncaused 'contingent beings' nor 'impossible entities.''Essence,' (mahyya) is used by ibn Sina in the sense of "ti esti" and in the secondary sense of "ousia" employed by Aristotle. (5) An existent partakes of an essence; for example, the feature of a basket-hall can be discussed in terms of the formal properties of a sphere. An unrealized entity such as a unicorn may have an essence but no existence."

(1) A. Maurer, Medieval Philosophy, New York, 1962, p. 94; F. Copleston, A History of Philosophy, New York, 1962, vol. II pt. 1 p. 215.

(2) Y. Mahdavi, Bibliographie d'ibn Sina, Tehran, 1954; G. C. Anawati, Essai de bibliographie avicennienne, Cairo, 1950 [these Bibliographies are in Arabic]

(3) Al-Shifa'Al-Mantiq, ed. I. Madkour, et al. 4 vols. (Cairo, 1960).

(4) See A. Moody, The Logic of William of Ockham, New York, 1965 p. 137

(5) See P. Morewedge, The Metaphysica of Avicenna (ibn Sina), London, 1973 p. 313.

From: Parviz Morewedge, The Mystical Philosophy of Avicenna, Binghamton, Global Publications, 2001 pp. 1-2 and 20-21.


"The inspection of the llahiyyat reveals not only the importance of Metaph. α, 1-2 and Λ, 6-10, but also the particular way in which Avicenna reproduces these two loci of the Metaphysics in his work: first, the doctrines of α, 1-2 and Λ, 6-10 are somehow interconnected in the final section of the Ilahiyyat, the one dealing with philosophical theology (VIII, 1–X, 3); second, within this section the doctrine of α, 1-2 is placed before that of Λ, 6-10, and constitutes a sort of introduction to philosophical theology. It is possible that Avicenna read α, 1-2 and Λ 6-10 during his secondary education according to this same pattern. (...)

In sum, Avicenna's approach to the Metaphysics at the time of his secondary instruction had three main features: (i) it was not an extensive reading of this work in its entirety, but only of the essential parts of it, namely--on the basis of the evidence at our disposal--α, 1-2 and Λ, 6-10; (ii) these two loci were read in connection with one another, as elements of the theological part of the Metaphysics, in disregard of the ontological part of it; (iii) a was read as an introduction to Λ, 6-10 whereas books A, B-K of Aristotle's work were probably neglected." pp. 57-58

"The first specific endeavour of clarifying the relationship between ontology and theology within the [Aristotle's] Metaphysics took place, as far as we know, in Arabic philosophy. In post-Aristotelian Greek philosophy, this relationship was not perceived as problematic: it appears as a crucial issue neither in an independent "aporetic" treatise on metaphysics like Theophrastus' Metaphysics, nor in a reworking of the Metaphysics such as parts II and III of Nicholas of Damascus' Philosophy of Aristotle (at least judging from the extant portions of this latter work), nor in the commentaries on the Metaphysics by Alexander of Aphrodisias, Themistius, Syrianus and Ammonius/Asclepius. In Arabic philosophy the problem was determined by the "theologizing" interpretation of the Metaphysics offered by philosophers like al-Kindi, which derives proximately from the classifications of sciences of Late Antiquity and depends ultimately on Aristotle's perspective (iii) taken in isolation from the others. (*) Al-Farabi's reacted to al-Kindi's one-sided view of the Metaphysics: connecting himself with the commentatorial tradition of Alexander of Aphrodisias, Themistius and Ammonius/Asclepius, he had a broader view of the Metaphysics and in the Fi Agrad he clarified that Aristotle's work contains not only a theology, but also an ontology. (**) The background of the entire discussion is the relationship of falsafa and Islam: whereas al-Kindi emphasizes the theological part of the Metaphysics in order to assimilate Aristotelian metaphysics (and Greek metaphysics in general) and Islamic theology, al-Farabi stresses the distinction of metaphysics and philosophical theology and assigns a broader scope (and, implicitly, a higher rank) to the former with regard to the latter. Avicenna further develops al-Farabi's point of view, somehow incorporating in it al-Kindi's perspective, and presents the fullest and most articulated account of the relationship of ontology and theology within metaphysics in the history of Medieval philosophy.

Avicenna regards as very important to determine the subject-matter of metaphysics: he starts the Ilahiyyat addressing this issue and adding the "subject-matter" ( mawud), as we will see in Chapter 5, to the preliminary questions traditionally discussed by Aristotelian commentators at the beginning of their exegesis of Aristotle's works. He appears to be the first in the history of philosophy to have devoted to this issue a separate and articulated treatment, and his contribution in the first two chapters of Ilahiyyat (I, 1-2) has rightly attracted the attention of scholars. (***) In Avicenna's powerful synthesis, Aristotle's different perspectives on the issue are elucidated and harmonized. As we are going to see in the first part of the present chapter, the main elements of Avicenna's discourse are five. First, he starts with a notion of metaphysics that gathers points (iii) and (i), namely the idea that metaphysics deals with immaterial things and with the first causes and the absolute Prime Cause, i.e. God. Second, he adds point (ii) to point (i) by means of the distinction between the "subject-matter" of metaphysics and the "things searched" in it: according to Avicenna, "existent qua existent", rather than God or the first causes, is the subject-matter of metaphysics. God and the first causes are things searched in metaphysics, and can be taken into account by this discipline just because they are not its subject-matter, for the subject-matter of a discipline is something that is common to all the things searched by the discipline in question, without being itself one of them. Third, he brings to unity perspective (iii) and perspective (ii) by means of a peculiar notion of "existent", according to which this concept is immaterial in as much as it is not restricted to the sphere of material things. Conceived as immaterial, "existent" can be common to all the objects of research of metaphysics. Fourth, he reaches a synthesis between perspective (i) and perspective (ii) by stressing that the first causes and God are a part of "existent" and the principles of the "existent" that is caused. Fifth, he stresses that the first causes and God, despite not being the subject-matter of metaphysics, have nonetheless a fundamental function within this discipline: among the things searched by metaphysics, they are its "goal", namely the things whose knowledge is ultimately pursued." pp. 113-114.

(*) See Chapter 2, 6-7.

(**) See Chapter 3, 2.

(***) See Fakhry [1984]; Davidson [1987], pp. 284-288; Hasnawi [1991]; Roccaro [1994]; Ramon Guerrero [1996]; Bertolacci [2001b] pp. 230-232, 259-261.

From: Amos Bertolacci, The Reception of Aristotle's Metaphysics in Avicenna's Kitab al-Sifa'. A Milestone of Western Metaphysical Thought. Leiden: Brill 2006.

"Martin Heidegger claims that the history of metaphysics is a history of the oblivion of being while propounding that his "fundamental ontology" presents a "genuine" account of the question of being that attempts to overcome metaphysics and its oblivion of being. Yet, it is perhaps doubtful that, for more than two thousand years (from Aristotle to Edmund Husserl), no philosopher was able to come up with a "genuine" approach to the question of being, and that no philosopher attempted to overcome the metaphysical history of the oblivion of being. This issue becomes more polemical and problematic, given that it is unlikely the case that in the global intellectual history of Chinese, Jewish, or Islamic philosophy, no philosopher or philosophical tradition has successfully attempted to overcome the history of the oblivion of being. In the case of Islamic philosophy, it is well documented that the Near Eastern Muslim world of the Middle ages has had an impact on the intellectual history of Western science and metaphysics. However, it is not yet well documented that the same Near Eastern Islamic philosophical tradition does indeed testify to the development of a phenomenological philosophical tradition that took the question of being to be the most central question of philosophical investigations. Considering the particular case of the physician, philosopher, and poet: Avicenna ([Ibn Sina] 980-1037), it is known that his influential al-Qanun fi al-tib (Book on medicine) was translated into Latin ( Liber Canonis) and many other languages, and was in currency since the late Middle ages and early Renaissance in Europe. It is also known that Avicenna's philosophical works have had a strong impact on Thomism and on the works of Maimonides among others. Moreover, Avicenna's philosophical contributions constituted the milestones of a phenomenological mode of investigation in ontology that impacted subsequent philosophical developments in the Near East, up to the recent modem times, and some investigators have already depicted some of the phenomenological dimensions that characterize his views."

From: Nader El-Bizri - The Phenomenological Quest between Avicenna and Heidegger, Binghamton, Global Publications, 2000 pp. XIII-XIV.


"For Ibn Sina, metaphysics is basically the study of "being qua being", but he immediately adds that its most noble, although not its first object is God, the Necessary Being by virtue of itself. (3) All this implies that the existence of God is not self-evident, but has to be proven. In order to do so, Ibn Sina develops his theory of the essence/existence distinction. In God, His essence is His existence, while in all other Beings one has to sharply distinguish their existence from their essence. (4) In the latter case, he qualifies the existence as being not identical with, but "accidental" to essence. Ibn Rushd saw in it a simple affirmation of the pure accidentality of existence, and therefore vehemently criticized Ibn Sina on this point. (5) Till recent times, this latter interpretation remained the standard one in the West. F. Rahman seems to have been the first contemporary commentator to have seriously put into question such an understanding of Ibn Sina's affirmation. (6) However, it deserves to be stated that already Henry of Ghent, in the late thirteenth century, was aware of the fact that the restricted Aristotelian notion of "accidentality" was surely not involved here, but a larger one. (7)

Among the vast majority of the Latin scholastics who followed Ibn Rushd's line of interpretation, was Thomas Aquinas. However, he accepted as most valid Ibn Sina's distinction between essence and existence, (8) a fact already evident from the very title of his famous early work De ente et essentia. Thomas Aquinas uses Ibn Sina's theory in order to explain the composite nature of all creatures, especially the immaterial ones, i.e., the angels. He obviously rejects any kind of hylemorphic composition in them. Although he does not mention the Avicennian vocabulary of "necessary in virtue of itself', "necessary in virtue of another", and "possible", he clearly derived his view from Ibn Sina, and not from Aristotle, Boethius, or the Liber de Causis as he suggests. (9) But, on the other hand, Thomas wants to distance himself from what he considers to be Ibn Sina's "essentialism". For him, there is not only identity in God between essence and existence, but God is above all " esse subsistens", which clearly means that the priority is on the side of the existence. Thomas certainly believed that he thus was radically opposing Ibn Sina's view. Even if he misunderstood the accidentality of existence in the latter's thought, he was right in his opinion that Ibn Sina had not fully appreciated existence as a part of the integral ontological dimension of Beings.


I have already stressed that for Ibn Sina, metaphysics was essentially the study of being qua being, i.e., an ontology, but that its most noble object of investigation is God, in other words it also includes theodicy. One may add that for Ibn Sina metaphysics is moreover the science that has to demonstrate the principles of the other sciences, which means that it also deals with the "archaeology" of the sciences. Although Aristotle's metaphysics entails elements of all three of these views, it never linked them together within a substantial unity. Based on the important preparatory work of his predecessor al-Farabi, for the first time in the history of philosophy Ibn Sina had worked out a metaphysical "system" as "system". In this respect this latter rightly deserves to be qualified as a kind of onto-theology even if it does not completely match Heidegger's – inspired by Duns Scotus – conception. In view of all this, metaphysics is certainly the highest and most valuable of all sciences, a fact particularly underlined by Ibn Sina when he discusses, in his Danesh-Nameh, metaphysics immediately after the "instrumental" science of logic, but before "physics", and such contrary to the customary habit, a habit he himself respects in his Arabic encyclopaedias, of presenting it as the latest of all sciences. While it is commonly designated as "meta-physics", i.e., the science of what comes after physics, an appellation sometimes used by Ibn Sina as well, he does not hesitate to call it Ilahiyyat, i.e. "(science) of the Divine Things" as well, and indeed prefers to do so."

(3) This is a common doctrine in his writings, clearly expressed in his major writing al-Shifa, al-Ilahiyyat, vol. I, eds. G.C. Anawati and S. Zayed, Cairo, OGIG, 1960, book I, chapters 1-2. This text is also available in a mediaeval Latin translation, see S. Van Riet (ed.), Avicenna Latinus. Liber de philosophia prima sive scientia divina, I–IV, Louvain, Peeters; Leiden, Brill, 1977, Tractatus primus, capitula 1-2.

(4 )This idea is omnipresent in Ibn Sina's metaphysical works too. Again, I refer only to al-Shifa, al-Ilahiyyat, but now vol. II, eds. M.Y. Musa, S. Dunya and S. Zayed, Cairo, OGIG, 1960, book VIII, chapter 4; for the Latin translation, see S. Van Riet (ed.), Avicenna Latinus. Liber de philosophia prima sive scientia divina V-X, Louvain, Peeters; Leiden, Brill, 1980, Tractatus octavos, capitulum 4.

(5) See e.g., Ibn Rushd, Tafsir ma ba'd al-Tabia, ed. M. Bouyges, Beirut, 1938. Repr. Tehran, Int. Hikma, 1377 H.S., vol. I, commentary on book Gamma, C 3, p. 313; there exists a medieval Latin translation, see Averroes, Opera omnia, Venetiis, Junta, 1562, vol. VIII, f. 67 B.

(6) F. Rahman, "Essence and Existence in Avicenna", Medieval and Renaissance Studies 4 (1958), pp. 1-14; see also ID., "Essence and Existence in Ibn Sina. The Myth and the Reality", Hamdard Islamicus 41 (1981), pp. 3-14.

(7) See P. Porro, "Possibility ed esse essentiae in Enrico di Gand", in W. Vanhamel (ed.), Henry of Ghent. Proceedings of the International Colloquium on the Occasion of the 700th Anniversary of His Death (1293) (Ancient and Medieval Philosophy, Ser. I, vol. XV), Leuven, Leuven University Press, 1996, pp. 211-53, especially p. 215.

(8) There exists ample literature on this subject. For references, see my An Annotated Bibliography on Ibn Sina (1970-1989) (Ancient and Medieval Philosophy, Ser. I, vol. XIII), Leuven, Leuven University Press, 1991, pp. 244-250 and my An Annotated Bibliography on Ibn Sina. First Supplement (1990-1994) (FIDEM, Textes et études du moyen age, 12). Louvain-la-Neuve, FIDEM, 1999, pp. 137-161.

(9) See Thomas d'Aquin. Dietrich de Freiberg, L'être et l'essence. Le vocabulaire médiéval de l'ontologie. Traduction et commentaires par A. de Libera et C. Michon (Points. Essais, 339), Paris, Editions du Seuil, 1996, pp. 27-36.

From: Jules Janssens, Ibn Sina and His Influence on the Arabic and Latin World, Aldershot, Ashgate, 2006, I, 1-2 and 6-7.


" behooves us to commence making known the ides of metaphysics. (...)

The philosophical sciences, as has been pointed out elsewhere in [our] books, are divided into the theoretical and the practical. The difference between the two has [also] been indicated. It has been mentioned that the theoretical are those wherein we seek the perfecting of the theoretical faculty of the soul through the attainment of the intellect in act -- this by the attainment of conceptual and verifiable knowledge through things that are [the things] they are, without [reference to their] being our [own] actions and states. Thus, the aim in these [things] is to attain an opinion and belief which is not an opinion and belief pertaining to the manner of an action, or to the manner of a principle of an action inasmuch as it is a principle of action. And [it has also been stated] that practical [philosophy] is that wherein one first seeks the perfection of the theoretical faculty by attaining conceptual and verifiable knowledge involving things that are [the things] they are in being our own actions -- thereby attaining, secondly, the perfection of the practical faculty through morals.

It was stated that theoretical knowledge is confined to three divisions -- namely, the natural, the mathematical, and the divine.

[It was also stated] that the subject matter of the natural is bodies, with respect to their being in motion and at rest, and [that] its investigation pertains to the occurrences that happen to them essentially in this respect.

[It was also stated] that the subject matter of mathematics is either that which is quantity essentially abstracted from matter, or that which has quantity -- the thing investigated therein being states that occur to quantity inasmuch as it is quantity and where one includes in its definition neither a species of matter nor a motive power.

[Finally, it was stated] that the divine science investigates the things that are separable from matter in subsistence and definition.

You have also heard that the divine science is the one in which the first causes of natural and mathematical existence and what relates to them are investigated; and [so also is] the Cause of Causes and Principle of Principles -- namely, God, exalted be His greatness.

This much is what you would have come to know from the books that have previously come to you. But from this it would not have become evident to you what the subject matter of metaphysics really is (except for a remark in the Book of Demonstration, if you remember it). This is because in the other sciences you would have something which is a subject; things that are searched after; and principles, [universally] admitted, from which demonstrations are constructed. But now you still have not truly ascertained what is the subject matter of this science -- whether it is the essence of the First Cause, so that what one seeks here is knowledge of His attributes and acts, or whether the subject matter is some other notion." pp. 2-3 (Book One, Chapter One).

"Hence, we must inescapably indicate the subject matter of this science so that the purpose that lies in this science becomes evident for us. (...)" p. 7

"Moreover, [the subject matter of metaphysics] cannot be specifically confined to any one category, nor can it be the attributes of any one thing except the existent inasmuch as it is an existent.

It is thus clear to you from this totality [of what has been said] that the existent inasmuch as it is an existent is something common to all these things and that it must be made the subject matter of this are for the reasons we have stated. And, moreover, because it is above the need either for its quiddity to be learned or for itself to be established so as to require another science to undertake to clarify [such] a state of affairs therein ([this] because of the impossibility of establishing the subject matter of a science and ascertaining its quiddity in the very science that has that subject), [it thus needs] only the admission of its existences and quiddity. The primary subject matter of this science is, hence, the existent inasmuch as it is an existent; and the things sought after in [this science] are those that accompany [the existent,] inasmuch as it is an existent, unconditionally." pp. 9-10 (Book One, Chapter Two).

From: Avicenna, The Metaphysics of the Healing. A Parallel English-Arabic Text Translated, Introduced and Annotated by Michael E. Marmura, Provo, Utah: Brigham Young University Press 2005.


"What adheres necessarily to this science [therefore] is that it is necessarily divided into parts. Some of these will investigate the ultimate causes, for these are the causes of every caused existent with respect to its existence. [This science] will [also] investigate the First Cause, from which emanates every caused existent inasmuch as it is a caused existent, not only inasmuch as it is an existent in motion or [only inasmuch as it is] quantified. Some [of the parts of this science] will investigate the accidental occurrences to the existent, and some [will investigate] the principles of the particular sciences. And because the principles of each science that is more particular are things searched after in the higher science -- as, for example, the principles of medicine [found] in natural [science] and of surveying [found] in geometry -- it will so occur in this science that the principles of the particular sciences that investigate the states of the particular existents are clarified therein.

Thus, this science investigates the states of the existent -- and the things that belong to it that are akin [to being] divisions and species -- until it arrives at a specialization with which the subject of natural science begins, relinquishing to it this specialty; [and at a] specialization with which the subject matter of mathematics begins, relinquishing to it this specialty; and so on with the others. And [this science] investigates and determines the state of that which, prior to such specialization, is akin to a principle. Thus, [some of] the things sought after in this science are the causes of the existent inasmuch as it is a caused existent; some [of the things sought after] pertain to the accidental occurrences to the existent; and some [pertain] to the principles of the particular sciences.

This, then, is the science sought after in this art. It is first philosophy, because it is knowledge of the first thing in existence (namely, the First Cause) and the first thing in generality (namely, existence and unity).

It is also wisdom, which is the best knowledge of the best thing known. For, it is the best knowledge (that is, [knowledge that yields] certainty) of the best thing known (that is, God, exalted be He, and the causes after Him). It is also knowledge of the ultimate causes of the whole [of caused things]. Moreover, it is knowledge of God and has the definition of divine science, which consists of a knowledge of the things that are separable from matter in definition and existence. For, as has become clear, the existent inasmuch as it is an existent, and its principles and the accidental occurrences [it undergoes] are all prior in existence to matter, and none of them is dependent for its existence on [matter's] existence." pp. 11-12 (Book One, Chapter Two).

From: Avicenna, The Metaphysics of the Healing. A Parallel English-Arabic Text Translated, Introduced and Annotated by Michael E. Marmura, Provo, Utah: Brigham Young University Press 2005.


On the website "Theory and History of Ontology" (

Selected bibliography on Avicenna's Logic and Metaphysics:

A - K

L - Z

Translations of the Philosophical Works of Avicenna (Ibn Sina)

Islamic (Arabic and Persian) Logic and Ontology

Index of the Pages on Medieval Philosophy from Boethius to ca. 1400


Gutas, Dimitri "Ibn Sina [Avicenna]", The Stanford Encyclopedia of Philosophy (Fall 2016 Edition), Edward N. Zalta (ed.)

Lizzini, Olga, "Ibn Sina's Metaphysics", The Stanford Encyclopedia of Philosophy (Fall 2016 Edition), Edward N. Zalta (ed.)

Rizvi Sajjad H., "Avicenna (Ibn Sina) (c.980—1037)", Internet Encyclopedia of Philosophy, James Fieser and Bradley Dowden (eds.)