Faith and Reason in Islamic-Christian Scholasticism:
Al-Ghazali, Avicenna, and Thomas Aquinas
Abstract:
This paper explores the extent to which Islamic discourse on faith and reason has been integrated into Christian scholastic theology. Al-Ghazali’s repudiation of Islamic philosophy does not necessarily exclude philosophical reasoning. A comparison between Al-Ghazali and Thomas Aquinas reveals shared views on miracles, revelation, and resurrection, with Aquinas incorporating elements of Aristotle-Avicenna reasoning into his theological framework. However, Aquinas’s critique of Averroes and Anselm remains contentious. Ultimately, the Protestant Christian perspective, as articulated in the epistemological framework of Anselm and Barth, seeks to critically and constructively supplement Aquinas’s ideas to address contemporary challenges in the relationship between religion and science.
Historical Overview: Cultural Renaissance
Al-Mansur (r. 754–775) laid the foundation for the new Abbasid capital, Baghdad, on 30 July 762. This marked the beginning of the Arabic translation movement, which would soon flourish. In this context, Greek, Persian, and Indian sciences were synthesized with Arabic literature, Islamic jurisprudence (fiqh), and Islamic speculative theology.
During the reign of Caliph al-Mamun (r. 813–833), the Arabic translation movement reached its zenith. The political influence of the Muʿtazilites was solidified under his rule, attaining the status of religious orthodoxy. The House of Wisdom, established during this period, became the first institution of higher learning in both the Islamic and Western worlds.
Nestorian and Jacobite Christian intellectuals had previously worked at the Academy of Gundeshapur, a major center of study during the reign of Khosrow I (531–579) of the Sasanian Empire. The renowned Nestorian Christian translator Hunayn ibn Ishaq (809–877) and his associates made significant contributions by translating numerous works, establishing the standard Arabic philosophical lexicon with clarity and precision.[1]
This historical context represents an Arabic-Islamic intellectual constellation that enabled the development of falsafa, the Arabic-Islamic philosophical tradition, as exemplified by figures such as al-Farabi (c. 870–c. 950) and Avicenna (980–1037).
The Platonic corpus was interpreted through the lens of later philosophers, including Plotinus (204–270 CE) and Proclus (411–485 CE). Neo-Platonic concepts of the One and emanation significantly shaped the understanding of the One as a transcendent divinity, entirely and unequivocally simple. Creation emanates from the One-Good through the divine Intellect (Nous), analogous to the Demiurge in Plato’s Timaeus, and the world soul; from here, the human soul emanates. Within this unified framework, the One is regarded as the supreme principle of being and existence.[2]
On the other hand, Muslim Spain experienced its own intellectual Renaissance alongside cosmopolitan Baghdad. The caliphate of Córdoba under the Umayyad dynasty (929–1031) was marked by significant cultural, artistic, scientific, and commercial flourishing. It became the cultural and intellectual hub of al-Andalus (modern-day Portugal and Spain).
The most important philosopher in Islamic Spain was Ibn Rushd (1126–1198), known in the West as Averroes, born in Córdoba. Between 1169 and 1195, Averroes wrote a series of commentaries on most of Aristotle’s works, offering a more accurate interpretation than the Neo-Platonist-influenced Muslim philosophers such as Al-Farabi and Avicenna.
By Avicenna’s era, falsafa (Islamic philosophy) faced growing scrutiny from the prominent Asharite theologian al-Baqillani (d. 1013). His critique resonated with al-Ghazali, a century later, whose works helped shape the Asharite school of thought. Al-Ashari (d. 935), who had originally studied under the Mutazilite school, ultimately founded the Asharite theological tradition, which would become dominant in Sunni Islam. While the Mutazilites emphasized reason and logic, al-Ashari argued that faith was essential for understanding God’s revelation in the Quran. He also asserted that the Quran is the uncreated word of God.
This paper primarily focuses on al-Ghazali’s engagement with Islamic philosophy, particularly his critique of Avicenna, and Averroes’s rebuttal within the Arabic-Islamic intellectual milieu. I will offer a philosophical and theological analysis of Ghazali’s later affirmation of Aristotle’s model of causation, emphasizing Thomas Aquinas’s interpretation. The comparison between Aquinas’s agential theology and al-Ghazali’s Occasionalism will be explored, alongside an analysis of the relationship between Aquinas and Avicenna.
Subsequently, I will explore Christian scholastic theology, focusing particularly on Aquinas’s critique of Anselm, through the lens of Karl Barth. Barth’s synthesis of analogical reasoning and the agential model of concurrence provides a dogmatic theology that is both constructive and epistemologically rigorous. His approach addresses contemporary issues, particularly the interaction between science and religion, emphasizing divine action and God’s grace.
Ghazali’s Refutation of Philosophical Arguments
Al-Ghazali (1058–1111), of Persian descent, was one of the preeminent theologians and legal scholars in Sunni Islam. He established the framework for a comprehensive critique of the philosophical system. Ghazali examined the translations of Aristotle and Neo-Platonism in the writings of earlier Islamic philosophers, such as al-Farabi and Ibn Sina (Avicenna in Latin).
Avicenna, born in 980 CE in the town of Afshana near Bukhara (present-day Uzbekistan), was profoundly influenced by Aristotle. He is considered the progenitor of early modern medicine and a pivotal Muslim Peripatetic philosopher, shaped by Aristotle’s philosophy as interpreted by Plotinus.
In his Tahafut al-Falasifa (The Incoherence of the Philosophers), al-Ghazali engages in a significant critique and refutation of the philosophical doctrines of his time. Averroes, in his Tahafut al-Tahafut (The Incoherence of the Incoherence), written after al-Ghazali’s death, offers a rebuttal to Ghazali’s criticisms, further elucidating the philosophical stance.
This theological-philosophical discourse continues to inspire contemporary Islamic intellectual developments and also fosters ecumenical engagement with Western scholastic theology, particularly that of Thomas Aquinas.
One of Ghazali’s key critiques is aimed at the philosophical doctrine of the eternity of the world. According to some philosophers, the universe has always existed alongside God as His effect, coexisting in time. In Islamic philosophy, the priority of God over the world is not temporal but correlational—God is the cause, and the world is the effect. In this view, God precedes the world, but not in a linear sense of time; rather, the cause takes precedence over the effect.
Ghazali critiques Avicenna’s interpretation of Aristotle’s cosmology. For Aristotle, the cosmos is a synthesis of substance and form. Nature, as a principle of change and transformation, is dialectical and dynamic, encompassing both substance and form (or purpose). Entelecheia denotes the ongoing process of transformation or active existence, which is directed toward the ultimate goal (energia).
In this hylomorphism framework, there is a relationship between potentiality (matter, exemplified by an uncarved piece of wood) and actuality (the form of a table, as the realized state or substance). “Actuality is hot, while potentiality is cold; the actuality of potential, as potential, is change.”[3] Matter is the potential for something to exist in a particular way, taking on different forms. For example, the bronze of a statue represents its matter.
Avicenna says: “The form is something that prepares the matter in order that it be acted upon by some cause from an external agent that is accidental…”[4] Generation arises from pre-existing material. For the cosmos to exist, God, as the Unmoved Mover, must ‘create’ both matter and forms. Therefore, the universe was not created at a specific point in time; rather, it has existed eternally through a process of concurrence.
Creation ex Nihilo
To counter the idea of the world’s eternity, Ghazali argues that time itself is part of the created order. True creation, in the sense of creation ex nihilo (creation from nothing), necessitates that God is ontologically prior to creation. As such, creation exists or subsists solely through God’s ongoing creative act.
Ghazali briefly mentions Plato, who is said to have held that the world had a beginning in time. However, Ghazali does not fully engage with Plato’s position in depth.[5] He finds it difficult to maintain that “something which has a beginning in time should proceed from the eternal without there being any intermediary.”[6]
In Timaeus, one of Plato’s dialogues, there is a distinction between the eternal world (which is apprehended by reason) and the physical world (which is understood through opinion and sensory perception). The demiurge, or divine craftsman, is the cause (or “father”) of the universe, creating it by looking to the eternal model or form. Out of its inherent goodness, the demiurge desires to shape chaotic matter into something good, like itself. The physical world is created as an “analogate,” a reflection of the eternal, the primary analogon, and is made a living being endowed with a soul (which precedes and is older than the body) and intelligence (27c-28b).
However, against Plato, Aristotle argues that anything generated must depend on an efficient cause. Aristotle’s God, the Unmoved Mover, is not merely an efficient cause of the cosmos’ existence. Rather, God functions solely as the final cause, explaining why the cosmos eternally changes and is in constant motion—echoing the ideas of Heraclitus.
But the beginning lies in change. If God is eternal, the universe must also be eternal, since it is continuous with God.[7] But God is one, living, and eternal, while everything comes into being from the underlying substance, with form or nature as the source of things’ movements and changes. Nonetheless, Aristotle understands the dialectical relationship between potentiality and actuality, or form and matter, by analogy. Actuality, in terms of becoming and time, is prior to potentiality. A is to B as C is to D in the analogy of proportionality, just as bronze is to a statue or wood is to a bed.[8]
An actuality in the agent through practice for fulfillment is prior in substance to an ontology of potentiality, tracing back to the actuality of the eternal Prime Mover, who exists actually and is prior in substance to perishable things. A philosophy of hylomorphism, which draws on both matter (potentiality) and form (actuality), assumes the pre-existence of matter, which is then structured and formed through change. This view stands in contrast to the concept of creatio ex nihilo.
However, Ghazali affirms the creation of the world in time through the eternal will of God, reacting against the philosophical claim that the connection between an eternal will and a temporal creation would be absurd.
To defend a philosophical position, Averroes in his response after the death of Ghazali argues that “the starting-point of His acts is at the starting point of His existence; for neither of them has a beginning.”[9] Thus, God and the world are correlative by virtue of concurrence. For Aristotle, God’s essential actuality is the highest good, eternal, and a living being, so that life and duration—continuous and eternal—belong to God.[10]
The living God participates in human life as aletheia, particularly through human contemplative activity, resembling Plato’s concepts of divine parousia (presence) and methexis (participation or imitation). Imperishable things are imitated or participated in by those involved in change, tracing back to the actuality of God, the final purpose.[11]
Aristotle appears to be a phenomenologist avant la lettre, with a dual concept of aletheia: one that moves from potentiality to actuality through dialectical dynamis, striving toward life-intentionality and its ontological and ethical realization (energia-actuality); the other, divine aletheia, which is present in and concerned with human intellectual activity, particularly contemplative thought. A dialectical process in the interaction between dynamis (potentiality) and energia (actuality) involves movement, change, privation through violence, and modification. This process adopts a critical attitude toward the natural attitude, questioning that which is typically taken for granted, in light of the actuality that challenges it.
Avicenna and Creation: Atemporal and Temporal
Ghazali is concerned with God’s infinite power in the creation of the world, emphasizing that divine power is not bound by the periods or constraints of created time. He challenges the philosophical assumption that time existed prior to the existence of the world.
In doing so, Ghazali appears to sidestep Avicenna’s distinction between two types of creation: “atemporal creation” (ibdāʿ), or absolute creation, and “temporal creation” (ḥudūth). In atemporal or absolute creation, nothing precedes the creative act of God, who is ontologically—though not temporally—prior to creation. An immaterial intellect, such as the Giver of Forms or Active Intellect (Nous), is atemporally created and serves as the ground for the emergence of created existence (Avicenna, Metaphysics, IV.2, 138.4–139.1).
As Jon McGinnis explains, the Necessary Existent is the eternally unchanging, complete cause of the cosmos’ necessary existence. Since effects must exist simultaneously with their complete causes, the cosmos must also exist eternally as something necessary through the Necessary Existent.[12]
Avicenna appropriates the Aristotelian model while incorporating Plotinus’ notion of the One-Good as the transcendence, thereby affirming the Islamic monotheistic tenet that emphasizes the world’s dependence on God. Avicenna’s metaphysics of creation aligns with the Quranic verses that describe the creation of the angel from divine light (Surah Fatir 35:1) and the creation out of nothing (Surah 2:117).
The necessary emanation or outflow originates from the ‘Necessary Existent’—God. However, the universe is not identical with God, since it is a projection from the Divine Plenitude and emanates as a distinct reality.
Neo-Platonic Metaphysics of the Soul
In Avicenna’s framework, the First Principle is the intellect, which is generated by the Necessary Existent analogous to the One-Good. Avicenna divides the rational soul into two faculties: knowing and acting, both of which are referred to as the intellect. Theoretical intellect serves as the foundation of science, while practical intellect underpins ethics. The reasoning soul enhances or realizes the natural body, which contains potential life, as posited by Aristotle. However, Avicenna endorses the Neo-Platonic concept of the soul’s immortality, arguing that the soul is not intrinsically bound to the body.
According to Ghazali, Avicenna posits that the souls of human beings are self-subsisting substances, acting as the directing or governing principle of matter. These souls are so self-originated that they pre-exist their physical embodiment. There is no essence or matter prior to the existence of these souls. Avicenna refuted Plato’s assertion that “the soul is eternal and that its relation to the body is accidental.”[13]
However, Avicenna also suggests that “their possibility is a relative attribute,” [14] meaning that the soul’s potential for existence is contingent upon certain conditions but does not exist as a distinct substance before its actualization. Avicenna follows Aristotle’s notion of the soul or the intellect, but incorporates the Neo-Platonic scheme of emanation.
In Plotinus’ interpretation of Aristotle, the Soul is an Ideal Form within corporeal matter, immortal and divine, free from sin. The Soul uses the body as a tool, and within it resides an essence—a self-subsistent being—that remains unaffected by the body and sensory perception. The concept of the Good pertains exclusively to the Soul, which transcends the limitations of the material world.[15]
Plotinus’s synthesis, which includes the contributions of Proclus (312-485), remains crucial in facilitating Augustine’s theology of the Trinity. Augustine recognizes in God three principles or hypostases: the One, or the Good, as the Father; the Intelligence, Mind, or Word of the Father as the Son; and the Soul as the universal principle of life. Augustine further asserts that the Holy Spirit is the Spirit of both the Father and the Son.[16]
Augustine’s theology of the Trinity initiated a paradigm for synthesizing God’s creation ex nihilo with the new life in birth (natality), rejecting the concept of the migration of the soul. “God can create new things—new to the world, but not to Him—which He never before created, but yet foresaw from all eternity.” [17] The fact that there is a beginning is demonstrated in the creation of the first man (Initum ergo ut esset, creatus est homo), implying the significance of birth and the potential for a fresh start through freedom and creativity.
In fact, Aristotle suggests that there is a part of the soul called the intellect, which might be separated from the body-soul entity. The soul is the actuality of a natural body, but the intellect appears to be a different kind of soul—immortal and eternal—able to exist independently from the perishable. Aristotle departs from the Platonic notion of soul migration, emphasizing one God who is living, free, and eternal.
Occasionalism and Divine Intervention
In contrast to Avicenna, Ghazali emphasizes the power of God as the foundation and explanation for the possible existence, situating it within a theological context. “God is eternal and omnipotent, and that if He wills, no action is impossible for Him. And this much does not necessitate the affirmation of an extended time…”[18]
Ghazali affirms the Quranic view of creation through Allah’s direct activity over six days (youm, meaning a long period of time) (Q 21:33, 7:54), which parallels the biblical account of Genesis. The Quran also states that “a day in the sight of the Lord is like a thousand years of our reckoning” (Q 22:47). However, creation is understood as an ongoing process through Allah’s continual power (Q 57:4), rather than a completed act followed by divine rest.
In fact, most Islamic speculative theologians adhered to occasionalism, reserving all causal efficacy or agency for God alone. Ghazali’s emphasis on God’s omnipotence is evident in his argument: if the occurrence of anything is due to God’s eternal will, “it makes no difference whether that which happens is existence or non-existence.”[19]
Ghazali’s position on occasionalism challenges the conventional cause-effect mechanism or necessary causation. According to him, the created order is not necessarily governed by secondary efficient causes but by God’s direct intervention. Everything that proceeds from God is a necessary consequence of His will.
However, I question how we can reconcile this view with the nature of the Quran as the eternal word of God. If the world is not eternal and was created temporally, does this imply that the Quran, too, must be temporal and created? If God alone is eternal, does this force Ghazali (perhaps against his will) to reject the eternal nature of the Quran? And, if the Quran is created, should we then interpret it according to logic, reason, and independent analysis, rather than viewing it as an eternal, unchanging divine revelation?
Averroes: Mutual Witness to God’s Truth
In summary of Ghazali’s major critiques, we find the following key points: (1) the connection between causes and effects as a logical necessity; (2) human souls as substances that exist independently, not imprinted on the body; (3) the immortality of the soul; and (4) the denial of bodily resurrection, meaning these souls cannot return to their bodies.[20]
Avicenna posits that upon the body’s death and decomposition, the essence of the soul is liberated from its association with the body. It is then drawn toward the celestial luminescence, the radiance of angels, and the heavenly realm. “Oh soul at complete rest, return to thy Lord, well pleased and well pleasing. Enter then among my devoted servants! Enter My heaven!”.’[21]
Ghazali defends the concept of corporeal resurrection against the philosophical notion of spiritual resurrection by clearly articulating its foundational principles. “After the death of the body, the soul continues to have an everlasting existence either in the state of indescribably great pleasure, or in the state of indescribably great pain. In some cases, the pain or pleasure will be everlasting; in others, it will pass away in the course of time.”[22]
Unlike Avicenna, Averroes firmly upholds the Quranic teaching on the resurrection of the body, positioning himself in contrast to Avicenna’s dual stance. For Avicenna, bodily resurrection can be denied, while spiritual resurrection is grounded in the immortality of the soul. This immortality, along with the soul’s eternal experience of happiness or pain, is supported by rational argument.
Averroes upholds the doctrine of bodily resurrection as a core principle of religion. The denial of the future life in the sense of bodily resurrection constitutes unbelief and must be eradicated. For him, “what arises from the dead is simulacra’ of these earthly bodies, not these bodies themselves,” because “that which has perished does not return individually and a thing can only return as an image of that which has perished.”[23]
Reason (philosophy) can align with faith while transcending traditional and literalist interpretations of the sacred text. In this context, reason seeks to understand faith in an intelligible sense, engaging with God’s mystery and power. This approach can be seen as a mutual witness to the ultimate truth, achieved through the recognition of each position’s distinctiveness and a non-contradictory understanding of the divine ultimate truth. It is characterized by a reconciling discourse on the distinction (between theology and philosophy) without separation, underlying the ultimate reality of Tawhid and the attributes of God.
Thomas Aquinas in Encounter with Islam Thoughts
During the first period of European engagement in the 12th and 13th centuries, Arabic philosophical writings had a profound influence on the great synthesis of Christian Aristotelianism, as exemplified by St. Albert the Great (1200-1280) and St. Thomas Aquinas (1225-1274).[24]
Albert the Great was a pioneer in compiling an encyclopedia of Aristotelian philosophy, drawing upon Aristotelian, Arabic, and Jewish writings in the twelfth century. Despite Pope Urban IV’s ban on the study of Aristotle’s works, by 1263, the Faculty of Arts in Paris had already organized the entire body of Aristotle’s teachings, paving the way for the development of a philosophical faculty independent from theology.
In the earlier century, Ghazali’s works were translated into Latin in Toledo, exerting a significant influence on Christian and Jewish thinkers of the medieval period. Ghazali may have entered Christian scholastic theology through St. Albert the Great, as Thomas Aquinas engaged deeply with the works of great Muslim philosophers. Additionally, the Quran was translated into Latin under the initiative of Peter the Venerable (1156), the last significant Abbot of Cluny.
Ghazali’s writings were studied intensively at the Toledo school by the Dominican Raymond Martin (d. 1285), a contemporary of Thomas Aquinas. Aquinas, in turn, incorporated Martin’s work Pugio Fidei into his own Summa Contra Gentiles.[25]
Aquinas’s project was to reconcile faith and reason, asserting that philosophy exists independently alongside theology. His approach, intelligo ut credam (“I know in order to believe”), contrasts with Augustine’s credo ut intelligam (“I believe in order to know”).
For Aquinas, a thing’s existence must be eternally caused, as God is the first source of all existence. All things originate from God (exitus) and return to God (reditus). Within this theological-philosophical framework of exitus and reditus, all things emanate from God and participate in God’s existence (Esse).[26]
This theological framework mirrors Plotinus’s concept of procession and return. Our participation is expressed through the beatific vision or mystical union with God. The process of deriving from the One-Good aligns with the emanationist interpretation, wherein the contemplation of the first principle imbues the emanation. In this view, emanation and contemplation are closely intertwined.
Agent Model and God’s Absolute Power
Ghazali and Aquinas share significant common ground in their views on the role of reason in demonstrating the existence of God, the relationship between faith and reason, miracles, and the resurrection of the body.
Aquinas takes issue with Plato’s teaching, in which the intellectual soul is not united with the body. In Plato’s view, the body is seen as the prison of the soul, with death marking the soul’s liberation; the soul itself is divine (Rep. 611e). The preexistence of souls is tied to Plato’s doctrine of transmigration and reincorporation (Phaed. 76e-77d).
Contrasting with the Platonic perspective, Aquinas argues that humans are created in the image of God and are endowed with intellect and will through the soul. Divine likeness, for Aquinas, resides primarily in the soul. The principle of understanding (referred to as the “mind” or “intellect”) is embodied in the human soul, which is incorporeal, subsistent, and possesses its own distinct activity.[27]
Aquinas follows in the footsteps of St. Paul, who speaks of the resurrection of the body rather than the immortality of the soul. According to Aquinas, the disembodied soul, after its separation, will be reunited with a body, joining Christ’s resurrected body. Thus, Christians believe in the future resurrection of the dead. [28]
However, Aquinas follows in Ghazali’s argument for the infinity of the soul in number: “Algazel responded to this in his Metaphysics saying that ‘in anything where there is one of these without the other,’ that is, quantity or a multitude without order.”… “Similarly we grant that human souls, which are separable from the body at death, are infinite in number, although they exist at the same time…”[29]
Ghazali does not deny the immortality of the soul, as it is affirmed in the doctrine of Resurrection. In the final part of Tahafut al-Falasifa, Ghazali seeks to address the problem of the world’s origin by exploring the possibility of the emanation of the temporal from the Eternal. He challenges both the traditional cause-and-effect mechanism and the concept of emanation.
For example, in the case of burning with fire, it does not necessarily prove that the fire causes the burning. Instead, God’s power serves as the basis—or even the cause—of the connection between things in empirical events.
However, Ghazali’s occasionalism becomes more nuanced in his later work, Mi’yar al-‘Ilm (Criterion of Knowledge), where he accepts the Aristotelian model of causation. In this later work, he advocates for demonstrative science, incorporating all four causes into his theological framework.[30]
Obviously, Aquinas favors Aristotle’s model of causation. He affirms that “God is the Cause of Activity in all Active Agents” and the cause of all things. God possesses infinite power and is present everywhere, in all things.[31]
The human will can contribute by acting, meaning that effects should be produced by the actions of creatures rather than by the direct intervention of God. Thomas rejects the occasionalist position, which argues that all effects are solely the result of God’s actions. “Fire does not warm, but God causes heat where fire is present.”[32]
Faith and Reason in Aquinas and Anselm
Aquinas rejects Anselm’s notion of God by stating: “Even if the meaning of the word ‘God’ were generally recognized to be ‘that than which nothing greater can be thought’, nothing thus defined would thereby be granted existence in the world of fact, but merely as thought about. Unless one is given that something in fact exists than which nothing greater can be thought—the conclusion that God in fact exists does not follow.”[33]
However, Aquinas’s reading of Anselm is misguided, as God’s transcendence in Anselm’s thought does not undermine the existence of God. Anselm, Archbishop of Canterbury (1093–1109), is regarded as the father of scholasticism. Influenced primarily by Augustine and Pseudo-Dionysius, his Neo-Platonic position drew from the works of Boethius (477–524) and incorporated Aristotelian logic.
Obviously, Aquinas identifies the prime mover with Christian God. For Aristotle “God is in a better state.” “And life also belongs to God; for the actuality of thought is life, and God is that actuality; God’s essential actuality is life most good and eternal. We say therefore that God is a living being, eternal, most good, so that life and duration continuous and eternal belong to God; for this is God.”[34]
If God is the first source of existence, creatures depend on God by sharing in the divine existence, which underpins His teaching of the analogia entis (analogy of being). The likeness between creatures and God comes through participation in some divine good and life, which is the analogia participationis (analogy of participation).
The rational creature, possessing existence, life, and knowledge, is most like God through proportionality (analogia proportionalitatis). Truth, goodness, and all similar attributes are predicated of God and creatures not univocally or equivocally, but analogically, according to varying degrees of perfection. The analogia attributionis (analogy of attribution) implies that the truth in God differs from the truth in creatures.[35]
In his proof for the existence of God, Anselm also articulates an analogical understanding of God’s incomprehensibility in relation to creatures, with an eschatological proviso that faith’s knowledge is ultimately limited; “per similitudinem, per analogiam.”[36]
Anselm’s notion of God implies divine aseity, meaning that God exists through Himself and from Himself, prior to all things, and creates all things ex nihilo (from nothing). Furthermore, Anselm treats the unbeliever’s quest as identical to that of the believer, as he dispels the apparent conflict between human rationality and faith.
“There is a solidarity between the theologian and worldling…but because he [the theologian] is determined to address the worldling as one with whom he has at least this in common—theology.”[37]
Anselm’s Proslogium refers to the discourse on faith seeking understanding of the divine Being, where faith in the revelation of God, or the Word of God, leads the believer to a deeper understanding of the mystery of God (Credo ut intelligam). God, “a being than which nothing greater can be conceived” “exists both in the understanding and in reality.”[38]
All things exist in God, yet God transcends them. The analogy between the Creator and the artisan is incomplete, as God’s existence permeates all things; He exists within them and through them, sustaining and encompassing everything. God’s participation in the world embraces all creatures.[39]
This is what Aquinas overlooks in his critique of Anselm’s proof for the existence of God. According to the Thomistic principle Gratia non tollit naturam, sed perficit (Grace does not destroy nature, but perfects it, ST I, I, 8 ad 2), grace builds upon nature rather than replacing it.
For Anselm, this principle is embodied in the Word of God, “the intelligence of the Creator,” [40] through which all things are created in Christ and fulfill their future actuality in the eschatological light of God’s mystery and eternity.
Anselm’s Christocentric focus and his analogical approach had a significant influence on Karl Barth. In the agential model, the Thomist position distinguishes between primary and secondary causes. God, as the primary cause, continues to sustain and conserve nature under divine providence. Natural agents are ordered toward divine goodness, bearing the likeness of divine grace—moved by God to act, and receiving a continual influx of divine power to be efficacious through human freedom.
This model of agency maintains that the source of a creature’s power to cause effects is rooted in divine causality. Therefore, God’s action within creatures is understood in a way that allows them to still exercise their own operations, while being moved by divine influence.[41] Thomas’s doctrine of concursus emphasizes divine activity as the primary agent, which does not render the activity of secondary agents redundant (Is 26:12; ST I, q. 105, art. 5, c).
In my opinion, Aquinas’s theory of concurrence does not supersede Anselm’s notion of God in solidarity with the world in an analogical sense. By the force of reason, Anselm argues that the term “good” is used analogically to describe things we experience, such as a horse being swift or strong.
Every analogy works according to some proportion, guided by the supremely good or true (God, the analogans who makes the analogy). The reality of the first good or true enters into every one of the things we call good or true (analogata, the things that are analogized). Anselm’s notion of truth is analogical in nature, grounded in the relationship between the analogans and the analogata.[42]
Anselm’s analogical thought does not contradict Aquinas’s analogy of cooperation, as it is not incompatible with human freedom. God grants human beings freedom while still being under divine providence as free agents. The primary cause grounds every existent without infringing upon their freedom.
However, Anselm’s analogy of God’s participation in the world differs essentially from Aquinas’s analogy of participation. For Anselm, all things apart from God participate in God’s existence, but the nature of this participation is distinct in both thinkers’ frameworks.
Avicenna and Thomas in Shared Views
Avicenna’s views on the question of God’s existence find an echo in Aquinas. In Aquinas’s Third Way, he argues that there are perishable beings (such as plants and animals) and imperishable, necessary beings. The imperishable, as Aquinas explains, is independent of anything else for its existence, which forms the basis of his cosmological argument for the existence of God. This concept of necessary existence in Aquinas can be compared to Avicenna’s proof of God as the Necessary Existent.
Moreover, both Avicenna and Aquinas share the view that created beings emanate from God. For Aquinas, the emanation of all beings comes from the universal cause, God, which he designates as creation.
“Hence if the emanation of the whole universal being from the first principle be considered, it is impossible that any being should be presupposed before this emanation.…so creation, which is the emanation of all being, is from the not-being which is nothing.”[43]
This emanative position contrasts with Aristotle’s concept of the prime mover, which does not generate or emanate but simply moves the matter of eternal things. Aquinas’s idea of creation ex nihilo takes on a Neo-Platonic twist.
Avicenna’s idea of emanation operates through the divine will of the Good (the very existence of the Necessary Existent). The One-Good, unchangeable and immutable (compared to light), is the source of the world, beyond all attributes and unaffected by emanation.
Avicenna’s understanding of the emanated Intellect (Nous) is associated with the celestial sphere. Through the contemplation of the first Intellect, another Intellect emanates—the soul of the celestial body or the world soul. This emanative process continues in a perpetual manner, influencing the multiplicity of forms in the entire cosmos.[44]
Nonetheless, Aquinas’s doctrine of creation through emanative action does not align with Avicenna’s notion of atemporal creation. Instead, it is tied to the doctrine of continuous preservation, or creatio continua, where God continually sustains and upholds creation.[45]
At this point, some questions arise regarding Aquinas: Is not God’s creation, in the biblical sense, carried out through God’s activity in the Word? If God not greater than that which has been created, “God is in all things, and throughout all; and all derive existence from it and exist through and in it.”[46]
Anselm’s perspective on God’s creative power and immanence offers an alternative to the blend of creatio ex nihilo and the concept of emanation. Furthermore, the Thomist doctrine of concursus has yet to fully clarify the relationship between the primary and secondary causes, especially in an overestimated view of human nature, reason, and history—tainted by sin and corruption, such as collective egotism, genocides, and wars.
Epilogue
In our analysis of Avicenna, Al-Ghazali, and Thomas Aquinas, we have explored the extent to which Avicenna embraces and reinterprets Aristotle for his own purposes. Al-Ghazali’s critique of Avicenna does not entail the exclusion of Avicenna or Aristotle from religious discourse. However, Ghazali’s argument requires further clarification, especially concerning his later endorsement of Aristotle’s causality model.
Within the Christian Scholastic framework, Aquinas engages with the works of Aristotle and Avicenna but is not confined by their systems. While there are notable similarities between Ghazali and Aquinas, the Thomist framework of divine and natural causes presents a distinct Christian interpretation of divine providence and human freedom, particularly in the context of divine concurrence. This framework fosters a unique dialogue between Christian and Islamic public theology, paving the way for a theology of divine action, especially in the context of the science-religion interaction.
From a Protestant perspective, Karl Barth employs the Thomist concept of concursus to preserve divine sovereignty while maintaining human freedom. Barth refines the agent model and incorporates a Catholic understanding of analogia entis, as proposed by German Catholic theologian G. Söhngen, who emphasized a Christocentric view of ontological participation in God’s grace.
The comprehension of God’s essence is inherently tied to understanding God’s actions (Esse sequitur operari—human knowledge of being follows the knowledge of divine activity). God’s being (esse) is revealed through divine acts (operari). To know God is to know Him through His Word and actions. The analogy of participation in the divine action cannot be understood solely through the analogy of being’s capacity for participation (Operari sequitur esse—action follows being, as a being’s actions are determined by its nature).
In fact, the analogia entis must be assumed by the analogia fidei, which sanctifies and elevates the analogia entis through Jesus Christ in the assumptio carnis.[47]
Obviously, the Word of God assumes human flesh, establishing an analogy of embodiment. Faith’s involvement does not contradict human participation in God, due to the divine efficacy of grace.
In modern theological discourse, it is difficult to fully align with Anselm’s transcendentalist stance, which minimizes the concept of divine passibility—an issue also absent in Aquinas’s thought. If God is compassionate and gracious, this is grounded in the divine revelation of God’s abundant love, forgiveness, and faithfulness (Ex.34:7). A compassionate and merciful God is one who ardently provides solace, like a mother comforting her child (Isa. 66:13). The names Allah Rahman and Raheem derive from the root word Rahim (womb), signifying a maternal love that is nurturing, compassionate, and enveloping, as seen in the Quran (Q 157).
An epistemology of faith and reason is inseparable from divine revelation (Torah, Christ, and the Quran), and this epistemology does not inherently exclude a framework of concurrence and co-participation between divine grace and human experience. This relationship of mutual collaboration can be understood in terms of convivencia—a living together. The double-agent paradigm of co-participation can be further explored and refined within the philosophical and theological evaluation of Christian-Islamic dialogue, especially when addressing modern challenges, as evidenced in the interdisciplinary study of science and religion.
God’s creation is continual in the sense of epigenesis, addressing an eschatological horizon of prolepsis through God’s reconciliation in Christ with the world. Faith and reason exist within a hermeneutical circle, mutually witnessing to God’s truth, undergirding a double-agent model of co-participation.
[1] Jon McGinnis, Avicenna (Oxford: Oxford University Press, 2010), 12.
[2] Ibid., 8.
[3] “Physics,” Book II. Ch. 8, in A New Aristotle Reader, 112. 108.
[4] Avicenna, The physics of The Healing I. 6, trans. Jon McGinnis (Provo, Utah:Brigham Young University, 2009).
[5] AL-Ghazali, Tahafut, 13.
[6] Ibid.
[7] Aristole, Physics. Bk. VIII, ch. 6.
[8] Aristotle, Metaphysics, Bk. Ch.6. 8.
[9] Averroes (Ibn Rushd), Tahafut al-Tahafut (The Incoherence of the Incoherence), E-text conversion
Muhammad Hozien, 146.
[10]Aristotle, Metaphysics, Bk. XV. Ch.7.
[11] Ibid., Ch, 8.
[12] McGinnis, Avicenna, 200.
[13] Al Ghazali, Tahafut, 222.
[14] Ibid., 49.
[15] Plotinus, The Six Enneads, trans. Stephen MacKenna and rev. B.S. Page (London: Faber, 1957), 7.
[16] St Augustine, The City of God (New York: The Modern Library, 1950), bk. X. 23.
[17] Ibid.,bk. XII. 20.
[18] Al-Ghazali, Tahafut, 45.
[19] Ibid., 62.
[20] Averroes (E-text): 407-8.
[21] Abd al-Rahman al Naqib, Avicenna, in Prospects, vol. XXIII, no. 1/2, 1993, 56 [Pp. 53-69].
[22] Al-Ghazali, Tahafut, 229.
[23] Averroes, Tahafut al-Tahafut, 470.
[24] Nicholas Rescher, Studies in Arabic Philosophy (Pittsburgh, Penn.: University of Pittsburgh Press, 1966), 156–57.
[25] St. Thomas Aquinas, Summa Contra Gentiles, trans. Joseph Rickaby, S. J. The electronic version (The Catholic Primer, 2005), 19.
[26] ST Ia.44.I.
[27] ST. Ia. 75.2.
[28] ST 3a.54. 4 ad.2.
[29] Aquinas, On the Unity of the Intellect against the Averroists (Milwaukee: Marquette University Press, 1968), Ch. 5. 117.
[30] Mehmet Vural, “Classic Logic of Al-Ghazali’s Methodology,” Journal of Islamic Research, vol.3. nr.2. (Dec. 2010), Pp. 143-148.
[31] Aquinas, Summa Contra Gentiles III, 67-68.
[32] Ibid., III, 69.
[33] ST Ia. 2. I ad.2.
[34] Aristotle, “Metaphysics” Bk. XII. Ch.7.
[35] An Aquinas Reader, ed. Mary T. Clark, 89-93.
[36] Karl Barth, Anselm: Fides Quaerens Intellectum (London: SCM press, 1960), 117.
[37] Ibid., 68. 43-4.
[38] “Proslogium” in St. Anselm Basic Writings, trans. S. N. Deane, 2nd ed. (La Sale, IL: Open Court, 1993), 54.
[39] “Monologium,” Ch, XIV. Ibid.,106.
[40] Ibid., 146.
[41] ST 1a.105.5.
[42] “Monologium,” ch, IV. St. Anselm Basic Writings, 89-91.
[43] ST Ia.45.I.
[44] McGinnis, Avicenna, 207-9.
[45] ST Ia. 104.I.
[46] “Monologue “XIV, in St. Anselm Basic Writings, 106.
[47] Barth, Church Dogmatics II/1: 82.