Received 25 March 2016; accepted 6 May 2016; published 9 May 2016
Avicenna’s doctrine of the Necessary Being (wajib al-wujud) has been widely discussed by Muslim and Western scholars. It has become the focal point of his metaphysics, and left a significant impact on Muslim and non-Muslim thinkers. Yet further study is needed in light of its distinction with Aristotle’s doctrine of the Primary Cause. I shall argue that Avicenna’s doctrine can be better understood when its difference from Aristotle’s doctrine is examined. To embark upon this, it is imperative at the outset to examine Aristotle’s doctrine of the Primary Cause, advocated in his Metaphysics. It is also equally important to determine what “necessary” in this context means for Avicenna and how it differs from the “possible”. As we know, for Aristotle whatever is primary and ultimate must be “simple” and with no reference to anything that is prior to it. This allows the primary being to have a greater claim to priority as well as necessary unity. If something is composite, it will be pre- conditioned ontologically, and postulates its own pre-existed components. Therefore it cannot become primary. Avicenna, like Aristotle, is aware of this problem and determines an existence of absolute simplicity and unity as the first principle by relying on essence-existence dichotomy. Following on from this whatever is determined as “necessary” will be dependent on the relation of essence to its existence rather than on the relation of matter to its form. This approach also indicates Avicenna’s intellectual independence, which is apparent in spite of his interest in Aristotle’s metaphysics.
2. Aristotle’s Prime Cause
An examination of Aristotle’s metaphysics reveals that his doctrine of the Prime Cause is based on the principle of prior simplicity. To demonstrate this, Aristotle draws a clear distinction between the Prime Cause and the world. The latter, for him, is not a simple being but either a composite of form and matter or a hylomorphic substance in the primary sense constituting the basic reality of the world. Every hylomorphic substance is also particular and signifies “this” as well as the essence (Aristotle, 1028a, 27) . Its essence is not distinguished from it, for “We must inquire whether each thing and its essence are the same or different. This is of some use for the inquiry concerning substance; for each thing is thought to be not different from its substance, and the essence is said to be the substance of each thing” (Aristotle, 1031a, 17-18) . Given this understanding of reality, there follows the question of whether or not a substance has a genuine unity.
Since a substance is a composite particular existent, it is unified because composition of any sort signifies a unity of two or more than two combining elements. But this unity is accidental, postulating the existence of its components, namely from and matter. The existence of a hylomorphic substance is very much dependent on form and matter, and therein matter becomes the potentiality of form and capable of receiving it (Aristotle, 1023a, 12; and 191a, 11 and 139b, 1) . It is then, possible to argue that matter and form must have existed independently prior to their accidental unity in each hylomorphic substance. Nevertheless, Aristotle does not advocate this view (Aristotle, 1033b, 6, 11, and, 210a, 20-21) . He does not advocate the existence of pure matter or pure form in the world―whatever is found and experienced is a composite of both.
After denying the possibility of having pure form and pure matter in the world in Physics as well as Metaphysics, Aristotle provides an interesting analysis of the intellectual soul in de Anima and de Generation. In these two texts, he advocates the idea that the intellectual soul of human beings―which stands for the human form―enters the body and is attached to it (Aristotle, 736b, 27-28) . This unity is compared to the unity a lump of wax achieves through its shape. The shape of wax can be easily modified and each new shape comes into being from the wax (Aristotle, 412b, 6-8) . However, this does not mean that Aristotle is in agreement with Plato on the theory of the pre-existing universal forms. This also indicates the possible separation of form and matter before their accidental unity. Through this analysis we will see that no hylomorphic substance can be thought of as the first principle having ontological priority. It is true that a hylomorphic substance is primary in the sense that other realities, whether in the form of natural or accidental universals, depend on it. A primary substance cannot be predicated of anything or be said to be in anything. They are also distinguished from secondary substances, which are universals and can be predicated. But a primary substance is still a composite entity, posterior and derivative. Aristotle uses a different set of criteria to argue with some perplexity that form, matter and the composite of both of them are three kinds of substances. Nonetheless as Terence Irwin remarks, “His argument does not support form to the exclusion of matter and compound, but simply implies that the legitimate claims of matter and compound depend on the prior claims of form” (Irwin, 2002: p. 266) . If “substance” is a particular or basic subject in a proposition, identified as “this” and the “what-it-is”, then it would be easy to find. In the meantime, the criteria set by Aristotle deal with hylomorphic substances. Following the principle of simple priority, it would be impossible for any hylomorphic substance to stand for the Prime Cause.
Aristotle is aware of this problem and for this reason he sought another kind of substance with absolute simplicity to become a prime cause. This new type of substance should be “matter” or “form”, pure potentiality or pure actuality. For Aristotle this new substance, unlike hylomorphic substances, is the purest, operating as the primary cause moving everything without being movable itself (Aristotle, 1073a1, 25) . The arguments for the existence of such a substance are based on the notions of interrupted movement and simplicity. In Metaphysics, Aristotle, denies “matter” to be this principle and believes that the prime cause should be “pure form” or “pure actuality”, stating, “There, must, then, be such a principle, whose very substance is actuality. Further, then, these substances must be without matter; for they must be eternal, at least if anything else is eternal” (Aristotle, 1071a1, 15-20) . At this juncture it becomes clear that there are two kinds of substances, hylomorphic and morphic substances with material and non-material existence. In this regard, only the pure substances have genuine unity because they are simple and not joined with matter. The pure substances are not found in the material world, they are intelligences of the planetary spheres, moving them from outside. The highest among them is the/The Prime Cause or the unmoved mover, whose existence is again a pure form or pure actuality. For many thinkers including Ammonius of Alexandria (early 3rd century A.D.), Aristotle’s interpretation of pure substances represents his agreement with Plato. It is believed that Porphyry (c. 232-c. 304 A.D.), and Simplicus (6th century A.D.), Farabi (c. 870-950) and others held similar views. Lloyd P. Gerson states that the debate regarding the agreement between Plato and Aristotle is primarily based on the view that Aristotle recognises the existence of a unique first principle or a prime cause quite different from and prior to the material world (Gerson, 2006: p. 11) . This prime cause should be one with absolute simplicity otherwise it cannot become the prime cause.
3. Avicenna’s Polarization of Existence
The view that Avicenna’s metaphysics is Aristotelian is based to some extent on the influence of Aristotle on this Muslim thinker. Avicenna employed Aristotle’s language in describing a number of philosophical problems. It is entirely reasonable to propound this point, but in no way will it lead to their reconciliation as Avicenna is not a staunch supporter of Aristotle and incorporated the doctrine of emanation in his philosophical system only to describe the structure of the world. Another significant difference between Aristotle and Avicenna relates to Avicenna’s doctrine of the Necessary Being (wajib al-wujud) elaborated in al-Shifa. As mentioned before, prior simplicity is a ground for any kind of being to become the ultimate reality. In Avicenna’s metaphysics this principle is associated with the essence-existence dichotomy. Indeed, Avicenna, like Aristotle, believes that the prime substances, which constitute the reality of all particular existents, are hylomorphic, “Let us [now] confirm [our] showing that every originated thing has a material principle, and thus we say in brief: Everything that is originated after not being must necessarily have matter. [This is] because every generated thing requires for its generation―before its generation-that it be possible of existence in itself” (Avicenna, 2005: p. 139) . He further states that “This corporeal matter cannot exist devoid of form in actuality” (Avicenna, 2005: p. 57) . No doubt these statements are coherent with Aristotle’s interpretation of the relationship between form and matter in the world, yet his understanding of the nature of the Necessary Being is not based on Aristotelian formula.
Avicenna’s metaphysics focuses on the ontological division of reality into necessary, possible and impossible. In this division every aspect of reality has specific nature determined by the relation of essence to existence. The generated existents are not necessary in themselves, but possible (mumkin). Their necessity is due to their cause or due to something else. They become necessary through association with what is necessary in itself. Existence does not belong to them except through an efficient cause. And so, a possible being cannot be said to be real or actual unless it has come to be. At the same time, they are capable of non-existence because they are caused by something other than themselves. In this case, it is possible to think of a time when every being of this kind can be and a time during which it cannot be. In this manner, whatever is generated becomes a possible being (mumkinwujud) or (al-maujud), and consequently, the being of a possible being is distinct from its essence. Its essence cannot be actual unless joined to an existence. This binary of essence and existence in possible beings is not the product of our intellectual analysis. It is not ascribed to thinking but rather to something real and present in the world. For every possible being is a composite, consisting of essence and existence. And then to know what something is, its essence should be revealed in definition. Essence becomes a ground for the possibility of knowledge about the possible beings. But as mentioned earlier, essence is not considered as something conceptual revealing itself only in a definition or having a logical existence in the mind, it is real as well. This is an important aspect of Avicenna’s understanding of “essence” and its relation to “existence” in the sphere of possible beings. Stephen Menn, for example, states that “The key, for Avicenna, is that the quiddity of which extra mental existence is predicated is not essentially a concept in the soul; rather, it is by its essence neutral to existing in the soul, as a concept, or existing outside the soul. It is not a concept which is capable of existing extra mentally; rather, the quiddity, which exists in the soul as a concept, can also exist extra mentally” (Menn, 2013: p. 153) . It is this neutral essence and not any universal concept, which predicates the existence of every possible being.
The distinction between essence and existence is in the ontological structure of every possible being. The structure of a possible being, like the unity of hylomorphic substances in Aristotle’s metaphysics, will eventually become accidental because its essence is separate from existence. It is then that no possible being is found without this dichotomy and accidental unity in the world. Since a possible being has a composite structure and is contingent, it needs to have been produced or caused. In this manner, it will become necessary not in itself but through something else, and necessarily a possible being with respect to its cause (Avicenna, 2005: p. 30; 1985: p. 262; 1957: p. 19) . A possible being is possible because its existence depends on the existence of its cause. This means that there is no possible being except by the efficient causation of its creator. Besides, since a possible being is caused, we can say that its essence precedes its existence, or as stated by Avicenna, its existence is something added to its essence. Only through a cause can an essence become a possible being. Otherwise, it will remain impossible. This binary demarcation displays again that in all possible beings essence and existence are distinct. They do not represent one another and are loosely attached.
Following the principle of simplicity, it could be argued that if the Necessary Being is composite of essence and existence, then it will not become ultimate and necessary in itself, and its existence will be caused by something other than itself. What is then, the ontological structure of the Necessary Being? It has already been argued that the Necessary Being should be simple and necessary in itself. Simplicity is the negation of any kind of duality and multiplicity in its existence. By acknowledging the binary demarcation between essence and existence, the structural difference between the Necessary Being and all possible beings will become apparent. As such, no possible being is, due to its composite nature, necessary in itself. But if we posit that the Necessary Being is simple, it should be either essence or existence, not a composite of both. If it is thought to be pure essence without existence, then it will be non-existent. As a consequence of this, the Necessary Being should be “pure existence” or existence without a separate essence. It should have no quiddity other than its individual existence (Avicenna, 2005: p. 274) . Likewise, the Necessary Being should either be a cause in itself or a cause by the other. If the Necessary Being is a cause by the other then its existence will become possible or it will be necessary by the other. It is therefore, a cause in itself. For this reason, this kind of being becomes the first principle and the ultimate cause for all possible beings.
A direct corollary of this analysis is that the Necessary Being must be uncaused and absolutely simple. As presented in the arguments above, simplicity becomes a distinctive characterization of the Necessary Being. Unlike the possible beings, the Necessary Being cannot be dissected. One cannot think about the essence of the Necessary Being as something different and separated from its existence, “The existence of the Necessary Being cannot at all be a composite, [deriving] from multiplicity. The true nature of the Necessary Being cannot be shared by another. From our verifying [all this], it follows necessarily that the Necessary Being is not [dependent on] relation, is neither changing nor multiple, and has nothing associated with His existence that is proper to Himself” (Avicenna, 2005: p. 30) . Here, the unity, independence and un-changeability of the Necessary Being specified rely on the simplicity of its existence. Since the Necessary Being is pure existence and not composite, its nature is not shared by another. The notion of absolute simplicity then leads to the notion of unity or “oneness”. The notion of oneness also signifies the uniqueness of its existence as uncaused and having no quiddity that would predicate it. For this reason, Avicenna believes that there is only one kind of this existence, and anything other than the Necessary Being is a possible being, “The Necessary Being must be one entity” (Avicenna, 2005: p. 34) . This intrinsic as well as numerical unity is the negation of genus and differentia for the Necessary Being. On one hand, the Necessary Being is the first principle transcending all possible beings, on the other hand, it is one and nothing is equal to it. Any attempt to define the Necessary Being will doom it to failure, because “… the First has no differentia. Since He has neither genus nor differentia, He has no definition. There is no demonstration of Him, since there is no cause of Him. For this reason there is no ‘why’ regarding Him, and you shall know that there is no ‘why-ness’ for His act” (Avicenna, 2005: p. 277) .
When we think about a being of which unity is predicated, we will realize that its unity postulates plurality of its attributes, for example, the unity of essence and existence in a possible being. Is it reasonable therefore to say when we are taking about the unity of the Necessary Being, its simplicity will be jeopardised? Avicenna tries to deal with this problem by establishing the unity of the Necessary Being on the ground of its oneness and absolute simplicity. Its unity cannot be interpreted in terms of a unity, which is posterior to its existence. In this case, the unity of the Necessary Being is in no comparison with the unity of possible beings, which are dual in nature. The Necessary Being is one and has a subsisting unity in the sense that its nature accepts no multiplicity. According to Stephen Menn, Avicenna has developed this idea under the influence of Yahya ibn ‘Adi (893-974) (Menn, 2013: p. 154) , a Jacobite Christian philosopher from Tikrit, who translated a number of Plato’s dialogues and Aristotle’s works into Arabic. He also wrote a number of books on topics such as existence, quiddity and the incarnation (cf. O’Leary, 1922: p. 112) . It is also reasonable to trace back Avicenna’s notion of unity and oneness of the Necessary Being to Mu’tazilites, a theological school founded in Basra and developed in Baghdad in the eighth century. In order to defend the unity of God, the followers of this theological school rejected the reality and eternity of divine attributes. They strongly advocated the notion of the unity of God.
The purpose for postulating the existence of a transcendent principle with absolute simplicity and unity in Avicenna’s metaphysics is to demonstrate an ontological foundation for multiplicity of the possible world. In a way, Avicenna is averting Aristotle’s interpretation of the Prime Cause and the metaphysical implication of the fourfold causation. For him, the idea of the “eternal matter” or hyle, stated by Aristotle, is not viable as it is indirect disagreement with the Qur’anic paradigm of creation ex nihilo. It is also equally challenging to maintain that the material world was created ex-nihilo. Under the influence of the Greek thought, Avicenna could not admit the creation of the world out of nothing. Hence, following Neo-Platonism, he described the creation of the world as “emanation”. The possible world was emanated from the Necessary Being and multiplicity emerged from the unity of its existence. The rise of multiplicity, however, does not affect its unity and perfection, because the Necessary Being is perfect and necessary in every respect. Now, in talking about the Necessary Being’s perfection, we have to deal with its knowledge, in the sense that its perfection must include knowledge as well. But does the Necessary Being know particular instances of its emanation? Before answering this question it should be remembered that the Necessary Being’s intellect is not of material and changeable objects. This is due to four reasons: first, any knowledge of such objects is empirical; second, since objects of sense-experience are variable, the content of this kind of knowledge will be changeable and inconsistent; third, empirical knowledge is posterior and produced by experience; fourth, empirical knowledge happens within time and is perishable. For these reasons, it is improbable to accredit empirical knowledge to the Necessary Being, which is knowledge about possible beings emanated from the Necessary Being.
According to Avicenna, knowledge of the Necessary Being is about self-knowledge. This view is reminiscent of Aristotle on God’s knowledge in Metaphysics. For Aristotle, God (the Prime Cause) is unmoved but intellectually active. Its thinking is not based on an external object but rather on its own thinking about the intelligible, “And thought thinks itself because it shares the nature of the object of thought; for it becomes an object of thought in coming into contact with and thinks its object, so that thought and object of thought are the same” (Aristotle, 1072b 13-30) . Since God’s thinking is the intelligible or it is thinking about thinking, there will be no distinction between the known and the knower. No distinction can be made between subject and object in God’s knowledge because its object is non-referential. A possible way of understanding this kind of knowledge, as suggested by Lloyd Gerson, is through Plato’s doctrine of the universal forms, and by thinking about the intelligible as something represented by pure universal forms (Gerson, 2006: p. 188) . This provides an interesting way of understanding what Aristotle means by thinking in an intelligible way. But this interpretation may not be precisely accurate because the Platonic forms are distinguished from the existence of the Demiurge and are external to it. In Parmenides, Plato clearly refutes the view that the universal forms be ideas in God’s mind (Plato, 1997: pp. 132 b-c) . But there are Muslim thinkers who argued against Plato’s disapproval. Ibn ‘Arabi, for example, maintains that the essences of possible beings are originally immutable ideas (al-a‘yan al-thabita) that pre-existed in God’s intellect before they came into existence in the process of emanation. These immutable ideas are objects of God’s knowledge and never change. They are also not possible beings but rather their ideas and as such are identical with them (Ibn ‘Arabi, 2004: pp. 109-111) .
Avicenna aims to protect simplicity of the first principle by not allowing any sort of ontological or epistemological dualism to befall its nature. The Necessary Being, whether as pure actuality or pure existence, cannot be separated from its essence because there is no discrepancy in its existence. If this is the case, and knowledge is about revealing the essence of something, then knowledge of the Necessary Being will be different from that of human beings as its knowledge is about itself, and this “itself” is not an “essence”. The question that arises then is about the kind of this knowledge. Since the Necessary Being has no essence to be known or revealed, its self-knowledge is purely about its own existence. On the other hand, one can continue to argue that since the world is an emanated form of its existence, the self-knowledge of the Necessary Being will certainly include knowledge of the world. But for the reasons mentioned above, the Necessary Being’s knowledge cannot be empirical. We also know that empirical knowledge reveals particulars or individual instances rather than universals. Consequently its knowledge will remain universal, “It can be in such a manner that it is universal (kulli), not particular” (Avicenna, 2008: p. 252) . Again, it should be remembered that this kind of knowledge is not about the Platonic universal forms. Rather it is knowledge of everything in the world and about the world in a universal way. The particularity of this universal knowledge is illustrated by Avicenna in an example wherein an astronomer knows that a certain star is at rest at a place and the star will move somewhere else later without experiencing it or without knowledge of the present moment as this temporal knowledge is changeable and will not remain the same, “Thus the difference is clear between knowledge of things which is changeable and particular [and] completely temporal, and the completely universal. Necessary Existence knows all things completely universally, so that everything, small and great, does not escape from its knowledge (‘ilm), as has become clear from our discussion” (Avicenna, 2008: p. 253) . The Necessary Being knows itself and all other things by virtue of its universal knowledge similar to the knowledge of the astronomer. It is neither particular nor does it change according to whether its object is or is not. Avicenna pursues his arguments further to demonstrate that the Necessary Being has knowledge of whatever happens in heaven and on earth. This argument is based on the notion of causation. The Necessary Being is the real cause of everything. In knowing itself as a cause it is able to know its own effect. From this, it follows that there is nothing in the world that cannot be accessed by its knowledge, “Rather, the Necessary Being apprehends intellectually all things in a universal way; yet, despite this, no individual thing escapes His knowledge. Not [even] the weight of an atom in the heavens and the earth escapes Him. This is one of the wonders whose conception requires the subtlety of an inborn, acute intelligence” (Avicenna, 2005: p. 288; 1985: pp. 234-237; 1951: p. 34) . However, the exclusion of particulars from the Necessary Being’s knowledge will dispute the traditionally conceived notion of God as an omniscient being. It will demoralize the theological doctrine of divine retribution. In my opinion, this is a reason for Avicenna to soften his position by claiming that the Necessary Being’s knowledge includes all particulars but in a universal way. On the other hand, by not including particulars in its knowledge, the Necessary Being will suffer privation resulting necessarily in its perfection being compromised.
Avicenna’s doctrine of the Necessary Being is developed in light of Aristotle’ principle of prior simplicity, as the first principle, the Necessary Being has absolute simplicity and unity. But Avicenna’s approach to determine the simple and unitary nature of his first principle is not established upon the distinction between matter and form. The simplicity and unity of the Necessary Being is grounded on the denial of essence-existence dichotomy. Besides, Avicenna does not describe the first principle as a pure substance. In fact, the term “pure substance”, which is the core of Aristotle’s metaphysics, finds no place in Avicenna’s metaphysics. For him the first principle is not a substance but pure existence and has no relation to its essence because it has no essence or its essence cannot be conceived as something different from its existence. Essence and existence, as two different aspects, are employed to describe the nature of possible beings in the world. It could also be concluded that since the Necessary Being is pure existence and not pure substance or pure form, one cannot think of it as a formal cause only. The idea of causation developed by Avicenna is different from that of Aristotle. For this reason, the Necessary Being’s knowledge includes particulars. Meanwhile, knowing the particulars by the Necessary Being is different from knowing them empirically. The Necessary Being does not have empirical knowledge and its knowledge of particulars is not derived from sense-experience. Yet, as the real cause, the Necessary Being is capable of knowing particulars, but universally.
 Avicenna (2008). Danish-namah-yi ‘ala‘I (Treatise on Knowledge, Dedicated to Prince ‘Ala’ al-Dawla). In S. H. Nasr and M. Aminrazavi with the assistance of M. R. Jozi, An Anthology of Philosophy in Persia (Vol.1). London and New York: I. B. Tauris in Association with The Institute of Ismaili Studies in London.
 Ibn ‘Arabi (2004). The Meccan Revelations (Vol. 2, selected text of al-Futuhat al-Makkiya, Presentation and translation from the Arabic under the direction of Michel Chodkiewicz, translated by Cyrille Chodkiewicz and Denis Grill). New York: Pir Press.
 Plato (1997). Parmenides. In Complete Works of Plato (edited with introduction and notes by John M. Cooper, associate editor D. S. Hutchinson). Indianapolis/Cambridge: Hackett Publishing Company.