Augustine (AD 354–430)
Authors: Matthews Gareth B. 
Published: September 2018

Augustine was the first of the great Christian philosophers. For well over eight centuries following his death, in fact until the ascendancy of Thomas Aquinas at the end of the thirteenth century, he was also the single most influential Christian philosopher. As a theologian and Church Father, Augustine was the person who did the most to define Christian heresy and so, by implication, to formulate Christian orthodoxy. Of the three most prominent heresies defined by Augustine - Donatism, Pelagianism and Manicheism - the latter two also have especially important philosophical implications. In rejecting Pelagianism and its thesis of human perfectibility, Augustine rejected one form of the principle, often associated with Kant, that ‘ought’ implies ‘can’, and in rejecting Manicheism, with its doctrine that good and evil are equally basic metaphysical realities, Augustine rejected one solution to the philosophical problem of evil.

The Categories may have been the only work of Aristotle that Augustine actually read. Plato he knew somewhat better. He seems to have been familiar with several Platonic dialogues and he clearly felt a special affinity for Plato and the Platonists, which is particularly evident in De civitate Dei (The City of God) and De vera religione (On True Religion). Although he could be said to have responded to classical Greek philosophy in consequential ways, it must be added that what he responded to had been filtered through Neoplatonism, Hellenistic scepticism and Stoicism. It was principally through the writings of Cicero that Augustine became schooled in the opinions of his philosophical predecessors, and it was through the works of the Neoplatonists that he developed his deep appreciation for Plato.

Augustine’s philosophy thus draws significantly on the philosophy of late antiquity as well as on Christian revelation. Its originality lies partly in its synthesis of Greek and Christian thought, and partly in its development of a novel ego-centred approach to philosophy that anticipates modern thought, especially as exemplified in the philosophy of Descartes. In his De trinitate (The Trinity) and De civitate Dei, Augustine presents a line of thinking that foreshadows Descartes’ famous cogito, ergo sum. Through his Confessionum libri tredecim (Confessions, more usually known as Confessiones), the first significant autobiography in Western literature, and also through his Soliloquia (Soliloquies), which is a dialogue between himself and Reason, Augustine introduced a first-person perspective to Western philosophy.

Early in his career, Augustine found himself attracted to philosophical scepticism. In his earliest extant work he offers his most extensive response to the main sceptical arguments of his day, including those that raise the possibility one might only be dreaming. His later responses to scepticism, though less extensive, are better focused; they concentrate on the self-knowledge he considers directly available to each knowing subject, including the knowledge that one exists. Taking the first-person perspective one can also develop, he tries to show, in his De trinitate, a convincing argument for mind-body dualism. But supposing, as he does, that each of us knows from our own case what a mind is raises, as Augustine is perhaps the first philosopher to realize, a problem about how one can ever know that there are minds in addition to one’s own.

Augustine’s account of language and meaning influenced the development of ‘terminist’ logic in the high middle ages. His thoughts on language acquisition in Confessiones provide a foil for Wittgenstein in the latter’s Philosophical Investigations. Yet, some of Augustine’s own reflections on ostensive definition in his dialogue De magistro (The Teacher) anticipate Wittgenstein’s own views on language learning.

Augustine develops what is described as an ‘active’ theory of sense perception, according to which rays of vision touch objects whose consequent action on the body is ‘noticed’ by the mind or soul. Although his ideas on sense perception are interesting, his most influential epistemological conception is certainly his ‘theory of illumination’. Instead of supposing that what we know can be abstracted from sensible particulars that instantiate such knowledge, he insists that our mind is so constituted as to see ‘intelligible realities’ directly by an inner illumination.

The modern concept of the will is often said to originate with Augustine. Certainly the idea of will is central to his philosophy of mind, as well as to his account of sin and the origin of evil. Strikingly, he uses psychological ‘trinities’, including the trinity of memory, understanding and will, to illuminate the doctrine of the Divine Trinity, where there is also a baffling unity in plurality. The theological warrant for this analogy Augustine finds in the biblical idea that God created human beings, and specifically the human mind, in his own image.

Augustine’s attempts to achieve a philosophical understanding of theology and religious belief set the framework for much later medieval and early modern philosophy. On the issue of how reason should bear on religious faith, Augustine develops the idea that reason should work out an understanding of what we must first accept on faith. Yet he also displays a keen sensitivity to those issues most likely to challenge one’s religious faith. Prominent among his concerns is the philosophical problem of evil, to which he offers what has proved to be perhaps the most influential type of solution.

Particularly striking is Augustine’s virtually lifelong preoccupation with human freedom and how the fact that human beings are free to make their own choices can be reconciled with the Christian doctrines of God’s foreknowledge, predestination and grace. Almost every important medieval philosopher in the Christian West would later contribute to the continuing effort to achieve a satisfactory reconciliation of these issues. It is significant that Leibniz, who gave the problem of freedom, foreknowledge, predestination and grace one of its most sophisticated treatments, also gave much of his philosophical attention to the equally Augustinian problem of evil.

Although Augustine did present an argument for the existence of God, it is his understanding of the divine attributes, and especially his insistence on divine ‘simplicity’, that is, on the idea that God is not distinct from his attributes, that has been especially influential on later thinkers. Also influential are his various attempts to understand the created world. Augustine made several important efforts, perhaps most notably in the last books of his Confessiones and in his De genesi ad litteram (The Literal Meaning of Genesis) to give a philosophically sophisticated account of the creation story in the biblical book of Genesis. His contrast between God’s eternity and human temporality set the stage for later medieval and modern discussions of these issues, and his discussion of the nature of time in Book XI of his Confessiones is sometimes taken to epitomize philosophy.

Augustine’s descriptions of mystical experience are among the most eloquent in Western literature; they belong among the classic texts of mysticism. However, Augustine’s attempts to understand ritual are perhaps more remarkable for the directness with which he identifies and confronts difficult issues than for the success of his efforts to solve them. Those efforts seem to be hobbled by his version of mind-body dualism.

Augustine is a thoroughgoing intentionalist in ethics. This feature of his thought, as well as his unflinching insistence that one can do what one knows one ought not to be doing, mark him off from ethicists of the classical Greek period. Yet Augustine also preserves in his own thinking important strands of ancient Greek thought. Thus, for example, his development of the doctrine of the Christian virtues includes an echo of Plato’s idea of the unity of the virtues. His insistence that ‘ought’ does not, in any straightforward way, imply ‘can’, distinguishes him, not only from his contemporary Pelagius, whom he helped brand as a Christian heretic, but also from most modern ethicists as well.

The philosophy of history Augustine develops in De civitate Dei initiates a branch of philosophy that came into full flower in the nineteenth century. Also in that same work Augustine makes an influential contribution to what has come to be called ‘just war theory’, an applied ethical theory that has continued to develop even into the latter half of the twentieth century.