In Islamic intellectual disciplines, there Arabic term ‘aql plays a role similar to that of “intellect,” “reason,” or even “mind” or “common sense” in English-language discourses. Etymologically derived from the root, ‘-q-l , whose basic verb is ‘aqala, “to bind or fetter [a camel],” some linguists and philosophers explained that the ‘aql is thus named because it is that which restrains the soul from that which is harmful or evil, or that which “binds” human beings to their Divine Origin, or that which “ties down” concepts, permitting comprehension and understanding. This root appears as a verb, but not as a noun, in the Qur’an, typically meaning “to understand,” for example:
Have they not journeyed upon the earth, that they might have hearts by which to understand or ears by which to hear? Truly it is not the eyes that go blind, but it is hearts within breasts that go blind. (22:46)
They say, “Had we listened or had we understood, we would not be among the inhabitants of the Blaze. (67:10)
‘Aql is typically taken to refer to the intellective faculty of the soul (nafs) or heart (qalb) by which human beings can understand the principles of reality underlying its multiform appearances. In Islamic philosophy and theology, it is the characteristic and defining feature of a human being, that which makes moral responsibility possible, and whose development and cultivation is our raison d’être. In most traditions of Islamic philosophy, the human intellect is the last link in a chain of divine intellects going back to God. The potential of the intellect (ʿaql) to achieve the blissful state of divine contemplation and knowledge that is the goal of human existence is actualized through the acquisition of knowledge, and, since the intellect is an immaterial substance, through ascetic exercises, discipline, and a balancing of the passions and bodily humors, which can cloud and weaken the functioning of the intellect.
However, certain traditions of Sufism and theology emphasized the limited and limiting nature of the ‘aql, contrasting it to the infinitely-flexible and receptive heart (qalb). Nevertheless, other traditions of philosophy, Sufism, and later theology identified the Aristotelian/Neo-Platonic Active Intellect (al-‘aql- al-fa‘āl) with the Archangel Gabriel or the Holy Spirit of Abrahamic cosmologies who is the bringer of revelation. In these traditions, the human intellect served as a kind of immanent or subjective revelation that complements, mirrors, and is connected to the origin of prophetic revelation. In this perspective, if God is like the sun, then the Active Intellect is like the moon, and the activated human intellect is like the full moon’s reflection on a placid lake on a perfectly clear night.
It is important to note that in all of these perspectives, the functions of the ‘aql include but also exceed those of the “rational faculty” (ratio in Latin) to include those of the medieval Latin intellectus, that is, the direct metaphysical perception of universal realities. These perspectives are perhaps best summed up in the distinction of the famous Sufi and poet, Jalal al-dīn Rūmī, between the partial intellect (al-‘aql al-juzwī), which is the instrument of rationality and ordinary learning, and the Universal Intellect (al-‘aql al-kullī) (which he calls “the Intellect of the intellect”), which is the purified intellect of prophets and sages and the instrument of direct intellection of things “as they are.” He writes:
What sort of thing could the partial intellect possess that is not possessed by the Universal Intellect? The partial intellect is unable to produce anything from itself that it has not first seen. These compositions, engineering feats and structures that people erect are not new compositions. Having seen something like them, human beings merely make additions. Those who truly produce something new form themselves are the Universal Intellect. The partial intellect can be taught, it is in need of teaching. But the Universal Intellect is the teacher; it has no needs…. Whoever possess a partial intellect is in need of instruction, but the Universal Intellect is the originator of all things. Those who have joined the partial intellect to the Universal Intellect so that the two have become one are the prophets and saints.
As the faculty of knowledge, the ‘aql is the main instrument of the Islamic philosophical tradition (falsafa), in both its theoretical and practical dimensions. Indeed, Al-Kindī (d. 873), the first great Muslim peripatetic philosopher, defined falsafa as “the knowledge of the reality of things within man’s possibility, because the philosopher’s end in his theoretical knowledge is to gain truth and in his practical knowledge to behave in accordance with truth.” As this definition suggests, the tradition of falsafa combines philosophical contemplation, rational demonstration, and ethical cultivation to free the intellect from its limitations and ultimately achieve the goal of human perfection and felicity (saʿāda).
Following the earlier Islamic philosopher, al-Fārābī, Ibn Sīnā describes four levels of the intellect’s potential development through proper training: (a) the material intellect (al-aʿaql al-hayūlānī), which is shared by all mankind and is simply the potential to acquire knowledge from the senses and reason; (b) the dispositional intellect (al–ʿaql bi’l-malaka), which is the level of the intellect attained when one has mastered the basic rules of knowledge and correct thinking and become habituated to putting them into practice; (c) the actual intellect (al-ʿaql biʾl-fiʿl), in which the intellect can arrive at knowledge by itself and generate its own intellectual activity; and finally, if one continues to train the intellect, one can reach the highest stage (excluding the level of the prophets, who, because of the perfection of their nature, have even greater intellectual possibilities), (d) the acquired intellect (al-ʿaql al-mustafād), in which the intellect perfectly mirrors the higher intelligible world, conjoining with the Universal or Active Intellect (al-ʿaql al-faʿāl), the source and home of all intelligibles and through whom all human knowledge is received by Divine outpouring (al-fayḍ al-ilāhī).
For Ibn Sīnā, the Prophets have a nature characterized by a perfect clarity of consciousness and a prefect imagination, which leads to a state of consciousness called the “sacred intellect” (al-ʿaql al-qudsī), which receives all knowledge, directly and without human instruction, from the Active Intellect. The Prophet’s perfect imagination also gives perfect sensible and verbal form to these intelligible realities, which he can communicate to others in the form of stories, parables, metaphors, and rituals to guide the development of their intellects. Herein lies the import of the rituals of religious practice from the perspective of falsafa: they promote and support the development of the intellect in imitation of the Prophetic model of perfect intellection. That is, revelation and its commands and prohibitions kindle the intellect, but the intellect is also necessary to comprehend revelation, and the two work together in a virtuous cycle to cultivate the human perfection of intellection.
Other traditions of philosophical Sufism and theology instead emphasized the limited and limiting nature of the ‘aql, arguing that it seeks to fit reality into its rational constructions, which are exceeded by reality itself. al-Ghazālī famously fell into period of extreme doubt and psycho-intellectual paralysis when he considered that just as the senses can be mistaken, and require an additional faculty to verify conclusions drawn from them, so too could the ‘aql be mistaken, and since it cannot circularly prove the validity of its own conclusions, so too must another faculty be needed to ground and confirm its conclusions. For al-Ghazālī and other Sufis, this form of knowledge beyond the level of the intellect (warā’ tawr al-’aql) is known as kashf (unveiling) or ma‘rifa (direct knowledge) and is bestowed by God to a sound heart (qalb salīm). The influential Sufi master, Ibn al-‘Arabī, emphasizes that one’s ‘aql must work in tandem with imagination and the heart to overcome these limitations and understand and conform oneself to the Real as it is, beyond one’s own rational constructions of reality. Nevertheless, in later traditions of philosophical Sufism, the universal or divine intellect (al-‘aql al-kullī or al-‘aql al-rabbānī ) plays a role somewhat similar to that of the acquired or active intellect in the Avicennan schema—that is, it is cultivated through spiritual exercises and its nearly-perfect knowledge of divine realities is both the means and goal of the process of human perfection. Some later philosophers, such as Mulla Sadra (d. 1636), similarly synthesized Avicennan and Sufi frameworks to create a system that seamlessly combines epistemology, ontology, and ethics, since it is through ethical practice and intellection that the intellect develops and is re-united with the Active Intellect and ultimately, God, Absolute Being.
As with the nafs, Islamic theories of the ‘aql were strongly influenced by the Qur’an, hadith, and traditions of Qur’anic interpretation, and in Shi’ite intellectual traditions, the numerous sayings of the Imams about the ‘aql (e.g. Imam Ja‘far al-Ṣādiq is reported to have said that “Intellect is that ability by which the Merciful God is worshipped and by which Heaven is attained”) profoundly shaped the development of the concept. These traditions interacted with and were interpreted in reference to various Greco-Roman philosophical traditions, especially the Platonic, Aristotelian, and Neo-Platonic, as well as their adaptations by Christian and Jewish authors. Islamic theories of ‘aql influenced Medieval Latin Christian philosophy, Jewish philosophy, and early modern European philosophy. Sufi critiques of the partial intellect and rationalism were taken up by Goethe and the Romantics. The traditions of Islamic philosophy, Sufism and theology, and their various syntheses have continued down to the present day (21st-century), and the nature, function, and limits of the ‘aql continues to be a major topic of debate. Finally, through his many works in both English and Persian, the contemporary Islamic philosopher Seyyed Hossein Nasr (b. 1933) has emphasized the intellectual (‘aqlī) dimensions of Islamic spirituality and the spiritual dimensions of Islamic intellectual (‘aqlī) traditions, especially philosophy and Sufism.
P. Adamson, “Avicenna and his Commentators on Self-Intellective Substances,” in D.N. Hasse and A. Bertolacci (eds), The Arabic, Hebrew and Latin Reception of Avicenna’s Metaphysics (Berlin: 2011), 97-122.
D. Black, “Knowledge (ʿIlm) and Certainty (Yaqīn) in al-Fārābī’s Epistemology,” Arabic Sciences and Philosophy 16 (2006), 11-45.
Davidson, Herbert Alan. Alfarabi, Avicenna, and Averroes on intellect: Their cosmologies, theories of the active intellect, and theories of human intellect. Oxford University Press, 1992
Chittick, William C. “Reason, intellect, and consciousness in Islamic thought.” In Reason, Spirit and the Sacral in the New Enlightenment, pp. 11-35. Springer, Dordrecht, 2011
Kalin, Ibrahim. Knowledge in later Islamic philosophy: Mulla Sadra on existence, intellect, and intuition. OUP USA, 2010.
Marmura, Michael E. “Avicenna’s Psychological Proof of Prophecy.” Journal of Near Eastern Studies 22, no. 1 (1963): 49-56.
Nasr, Seyyed Hossein, Three Muslim Sages: Avicenna, Suhrawardi, Ibn ʿArabi. New York: Caravan Books, 1997.
Nasr, Seyyed Hossein. The Garden of Truth: The Vision and Practice of Sufism, Islam’s Mystical Tradition. HarperCollins, 2007.
Rustom, Mohammed. The Triumph of Mercy: Philosophy and Scripture in Mulla Sadra. SUNY Press, 2012.
Treiger, Alexander. Inspired knowledge in Islamic thought: al-Ghazali’s theory of mystical cognition and its Avicennian foundation. Routledge, 2011
Yazdi, Mehdi Ha’iri. The principles of epistemology in Islamic philosophy: Knowledge by presence. Suny Press, 1992.