It is no secret that the classical philosophies of the Greco-Roman world were revived by Muslim and Christian thinkers.

Before the “recovery of Aristotle” I like to think that there were two main schools of thought in the Christian world. These are Christian Platonism, which was universal in the Church Fathers (people like St. Maximus the Confessor, St. Gregory of Nyssa, and especially Psuedo-Dionysus), and Augustinianism. Like his contemporaries St. Augustine of Hippo made a heavy use of the doctrines of Platonism, specifically the Neoplatonist's like Plotinus and Proclus as their writings were the most accessible and popular amongst the Fathers, and out of him a school of thought that bears his name started in the Western European world. I think a good definition of Augustinianism is “Christian Platonism with adjustments.” For example, the Augustinian definition of original sin is very different from how the Greek Fathers and other Latin Fathers understood it (that is an entirely different discussion). Augustine’s definition of original sin as not just having the tendency to sin but also inherit the moral guilt of Adam and Eve is completely foreign to the Platonic Corpus. After St. Augustine’s time, intellectually you took one of two accepted positions: The Christian Platonism of the Greek Fathers or Augustinianism. Platonism by itself in Western Europe would eventually be overridden by the Augustinian movement.

Beginning in the 8th century, Avicennism was an early attempt at reviving the Aristotelian metaphysical and ethical tradition in the religion of Islam and forming a synthesis with the ideas of Platonism. Avicenna’s Sufficientia, or The Book of Healing, is a vast encyclopedia of ideas in metaphysics, logic, psychology, and the natural sciences. Averroes, a contemporary of Avicenna, would go on to found his own synthesis suggesting that philosophy and faith were compatible writing his Incoherence of the Incoherence in response to Al-Ghazali’s Incoherence of the Philosophers. Ibn Arabi founded Akbarism, a branch of Sufi philosophy, and he expounded upon the idea of Wahdat al-Wujud or the Unity of Being. Ibn Arabi equates Wujud to God, arguing that God is the Necessary Being for causation much like how Aristotle formulates the idea of a primum movens, a primary uncaused cause. The Persian philosopher Suhrawardi sought to synthesize the work of Avicenna, Aristotelianism, and Platonism into what he called Ishraqi or Illuminationism in order to revive classical thought in his society (also looking to the texts of Zoroastrianism as well).

As a result of the intellectualism going on in the Muslim world the tradition of Scholasticism began with St. Anselm of Canterbury, seeking to use Platonic and Aristotelian ideas to defend the axioms of the Christian faith. One notable achievement from him is his ontological argument. High Scholasticism in the 13th and 14th centuries paved the way for three commentators on Aristotle: St. Thomas Aquinas, John Duns Scotus, and William of Occam. High Scholasticism would cause the popular Augustinianism of the day to be replaced by Aristotelian philosophy. The students of Aquinas and Duns Scotus, largely members of the Dominican Order and Franciscan Order respectively, created the intellectual traditions of Thomism and Scotism; Thomism was very popular and influential while Scotism was less popular and stuck mainly amongst the Franciscans but the two schools of thought borrowed much from each other. William of Occam’s students founded Occamism, the core tenet of it being nominalism, the denial of universal essences. This would be challenged by church authorities but never formally condemned just frowned upon. Second Scholasticism would take off between the 15th and 17th centuries with the rise of the School of Salamanca in Spain. Founded by Francisco de Vitoria the school put an emphasis on natural law ethics, just war theory, and speaking out against slavery in the America’s. Students of international relations and economics are indebted to the rise of this school. The school produced two great minds, Luis de Molina and Francisco Suarez. After their deaths, students of theirs would found Molinism and Suarezianism, taking ideas from both Thomism and Scotism. Scholastic philosophy entered a slight downhill during the Enlightenment as the entire cultural climate of the Western European consciousness was changing and becoming radically more secular. In the 20th century there was a serious revival. Thomism was divided into a couple of camps or schools. Strict Observance Thomism was represented by Reginald Garrigou-Lagrange; This is a hard reading of the Corpus Thomisticum that frowns upon comparing Thomistic theses with modern philosophies. Analytical Thomism was an attempt to bridge the analytical way of doing philosophy that we find in the anglophone world with classical Thomist propositions. The third school in mind which I have paid much attention to in my graduate program is Existential Thomism. Beginning with Ettiene Gilson, he saw Thomism as a philosophy concerned with the nature of Being or esse. A subfield of this school is Polish Existential Thomism usually just called Lublin Thomism, Phenomenological Thomism, the Lublin School, or simply “Lublinism.” Representatives such as Mieczysław Krąpiec and Karol Wojtyła (known to the world as John Paul II) stuck with the Gilsonian idea that philosophy should be an investigation of Being but attempted to do it via the methodology of phenomenologists like Edmund Husserl and Max Scheler. I am convinced that Lublin Thomism/Polish Existential Thomism uniquely rose as an attack on the Marxism and totalitarianism that plagued Post-war Poland.

However, Islam and Christianity spread into the Far East as well. When Christianity reached China in the 6th century people attempted to explain the overall message of the New Testament in Confucian, Daoist, and Buddhist terminology hence the writing of the Jingjiao Documents. The same can be said of Islam when it arrived in the Middle Ages. Great thinkers like Wang Tai-yü and Liu Chih pulled ideas from Confucianism, drawing heavily not only from the canon but also from the Neoconfucians, to explain the overall doctrine of Islam; this implies that they would have had some knowledge of Islamic philosophy and indirectly understood ideas from Platonism and Aristotelianism. The Jesuit missionaries did a lot of work in East Asia attempting to learn the culture. Matteo Ricci, studying Confucianism, wrote an apologetical work entitled The True Meaning of the Lord of Heaven arguing that there is nothing contradictory between Christianity and Confucianism and did a translation of the canonical texts of Confucianism, bringing them to a western audience for the first time in history. Ippolito Desideri visited Tibet and was the first westerner to actually grasp the previously unknown Tibetan language. He enrolled in courses at Sera Monastery and learned Buddhist philosophy and engaged in debates. He was puzzled by the ideas of reincarnation (which he calls in his journals “Pythagorean transmigration”) and the concept of sunyata or emptiness but what really astounded him was that there was no explicit mention of a Creator in Buddhism (if you read any esoteric work the idea is there but it is very hard to understand). Regardless, Buddhist moral philosophy (e.g. Four Noble Truths, Eightfold Path, Five Precepts) impressed him greatly and found none of this to contradict Christianity.

To conclude, the historical use of these philosophical tradition’s amongst people of the western religious mind hopefully paves the way for dialogue between traditions.