How Augustine Made Us More than Matter—and Immortal

The Conversion of St. Augustine, by Fra Angelico (c. 1395-1455).

St. Augustine was fascinated by the human soul. Before and after his conversion to Catholicism, he strove to understand its nature, its relation to the body, and its duration.  Augustine’s thinking on the soul, like the rest of his life, followed a tortuous path. In this article, I retrace the steps that led him to his developed understanding of the soul—an understanding that would shape subsequent Catholic teaching.

In his early days, Augustine thought that the soul was a fine material substance dispersed throughout the body. He could not accept the existence of a substance that lacked spatial dimensions: “Whatever was not stretched out in space, or diffused or compacted or inflated or possessed of some such qualities, or at least capable of possessing them, I judged to be nothing at all.”1 Augustine, therefore, starts off a materialist. But he changes his mind upon reading Plotinus, who teaches that God is an immaterial substance. Augustine reasons that, because we are made in the image and likeness of God, the human soul is also an immaterial substance: “when speaking of God, no one should think of him as something corporeal; nor yet of the soul, for of all things the soul is nearest to God.”2

Augustine, however, does not merely rely on the Christian doctrine of the imago Dei to prove his point. Instead, he develops a number of philosophical arguments to demonstrate the soul’s immateriality. One of these arguments is that because the soul’s cognitive objects are not limited spatially, the soul itself cannot be limited spatially; and because the soul cannot be limited spatially, it, therefore, cannot be a material body.3 Another argument is that because the soul thinks and wills, but a material body cannot think or will, the soul, therefore, cannot be a material body.4 A third argument is that we attribute moral qualities to the soul, but moral qualities cannot be spatially extended properties of a material substance (e.g., “justice cannot be three-dimensional”); so the soul cannot be a material substance.5

Augustine’s doctrine of the immateriality of the soul leaves him with a conceptual puzzle: how is the immaterial substance of the human soul related to the material substance of the human body? Neo-Platonic philosophy holds that the soul is independent of the body and, regrettably, trapped in the body, as if in a prison: “the body is (the soul’s) fetter and tomb.”6  The soul’s proper place, therefore, is apart from the body, and it should endeavor to escape the body at the earliest opportunity. Augustine cannot accept this view. His Christian faith teaches that God created man with a body, and that man’s body will rise on the last day and be united with the soul in paradise. So the body is not a mere prison. Augustine must part ways with the Neo-Platonists on this point.

Another option for Augustine is to follow Aristotle, as Aquinas does many years later, by averring that the soul is the form of the body. Augustine, however, dismisses this approach: “he regards the Aristotelian view that the soul is the body’s form as little more than a version of harmony-theory, one to which Platonists had already given short enough shrift.”7  Harmony-theory is too reductionistic, making the soul into a mere physical attribute of the body (e.g., health or well-function) and, thereby, precluding the soul’s immateriality. So Augustine concludes that he needs an account somewhere between strict Neo-Platonism and Aristotelianism.

The account he proposes is that the soul, although entirely distinct from the body, nevertheless, has a necessary relationship with a body.  Every soul “is the principle of life” and the governor of a particular body.8 The soul gives the body movement, and causes the body to act in accordance with its volitions. The soul’s very identity, furthermore, depends upon this relationship. Augustine compares the soul to a horseman.9 A horseman’s very identity depends upon his relationship to a horse: “To count as a horseman, a man has to ride a horse: that is, to be in charge of it, and use it in a certain way.”10 Likewise, to count as a human soul, an immaterial substance has to be in charge of a physical human body, and use it in a certain way. The soul, therefore, is not an alien substance forced into a relationship with a body. Rather, it is an immaterial substance that exists properly, and even necessarily, in relation to its body. Soul and living body are not antagonistic, but interdependent. The body needs the soul in order to live, and the soul needs the body in order to be a soul at all.

Settling the question of the relationship between soul and body, however, still leaves an additional question: what is man? Initially, Augustine wants to follow the Neo-Platonists, and to identify man with the soul only, even though the soul has a necessary connection to a material body: “Man, as he appears to us, is a rational soul, making use of a mortal and earthly body.”11 This approach makes sense, given that Augustine thinks the image of God is in the soul, not the body: “(man) is not called the image of God according to everything that pertains to his nature, but according to the mind alone.”12 Augustine, however, eventually changes his position. The trouble with his initial position is that identifying the man with the soul exclusively seems to undermine the Catholic doctrine of the Incarnation.  The Incarnation requires that Jesus’ identity include his body. As Athanasius points out, Christians “neither divide the body from the Word and worship it by itself, nor when we wish to worship the Word, do we set him far apart from the flesh.”13 When Jesus’ body suffers, he suffers, when his body dies, he dies, and when his body is raised, he is raised.  Jesus is not only soul, but also flesh. So Augustine is forced to reject “the Platonic and Origenist dichotomy which sees the soul as the whole of man with the body serving … as an instrument.”14 In lieu of the full Platonic doctrine, Augustine describes the soul as a “composite of two substances, a soul and a body.”15 Man is two things together, united into a single living unity.16 According to Augustine’s most mature definition, “Man is a rational substance consisting of soul and body.”17

At death, however, the soul is separated, and remains in existence on its own until the resurrection of the dead, when it is reunited with the body. It is important for Augustine to show, therefore, that the soul survives the death of the body. One of Augustine’s arguments for the immortality of the soul goes as follows: 1) The soul is the principle of life. 2) In order to die, the soul must take on the principle of death. 3) The principle of life and the principle of death are contraries. 4) Contrary principles are not compatible. 5) Therefore, the soul cannot die.18 A significant problem with this argument is that it proves too much.  If the argument is sound, then it seems to show that even things such as jellyfish and sponges, simply because they are alive and have principles of life, also have immortal souls.

Augustine relies more heavily on a second argument. This argument is from the eternality of truth, and goes as follows: 1) The truths of mathematics and the truths of logic exist always. 2) The truths of mathematics and the truths of logic reside in the soul—in other words, “the soul is the substance which bears mathematical and logical truths.”19 3) If the eternal truths of mathematics and of logic reside in a substance, then that substance must also be eternal. 4) Therefore, the soul is eternal. It does not die with the body. Here is one objection to the argument: “That which is known does not endow the knower with its own nature,” so the eternal nature of a mathematical truth does not necessitate the eternality of a soul that knows a mathematical truth.20 This objection misses its mark. Augustine does not say that what is known endows the knower with its own nature. Rather, he says that the truths of mathematics, unlike the physical facts instantiated in the world around us, are instantiated in the soul itself.

Another objection, however, is that the argument relies on a highly Platonic view of learning. On a common reading of Plato, we learn abstract truths by looking into our souls where the knowledge already exists and by drawing the knowledge out via memory.  Learning is a process of remembering what we already know innately, but unconsciously.  This creates a problem for anyone who cannot accept a strong Platonic view of learning.  On the other hand, if the Platonic view of learning is correct—and it still does have a few adherents in contemporary philosophy—then the Augustine’s argument is highly plausible.

A final argument is Augustine’s argument from desire. The argument from desire goes as follows: 1) “the aspiration to eternity is ontologically rooted in the essence of the human soul.”21 2) God created the essence of the human soul. 3) God would not have created the human soul with an essence directed to an impossible end. 4) Therefore, the human soul must be immortal. This argument was repeated frequently after Augustine’s death, and it “became a favorite argument among Augustinians, with St. Bonaventure, for example.”22  The application of the argument today, however, is limited. One of its three premises includes the existence of God, and most people today, who need to be convinced about the immortality of the soul, also doubt the existence of God. So the argument is rendered ineffective. On the other hand, the argument from desire can be quite encouraging and convincing for theists. So we do have some reason to revive it.

Augustine’s treatment of the soul has been enormously influential. The view that the soul is immaterial spread quickly around the Christian world of his time, thanks, in large part, to his endorsement, and it eventually became solidified Christian orthodoxy. It may seem strange to us today, but before and during Augustine’s time, the immateriality of the soul was not obvious. For some Christians, “as his fellow African Tertullian had preferred, the soul (was) material.”23 Augustine helped the immateriality of the soul to achieve its nearly universal acceptance amongst Christians (leaving liberal Protestants aside, of course). The Church also follows, and thereby legitimizes, Augustine’s judgment that the soul is a composite of body and soul. We can see this well over a millennium later in the Catechism of the Catholic Church: “The human person … is a being at once corporeal and spiritual.”24  Finally, Augustine helped Christianity to turn away from a great temptation: that of denigrating the body and viewing it as a prison of the soul. Today, the Catholic Church clearly follows Augustine in saying that the body is, in itself, good, and that the soul is created to abide in the body as a home rather than a prison. The Catholic understanding of the soul is permeated with Augustine’s thinking. We owe him a great debt.

  1. Augustine, The Confessions, trans. Maria Boulding (San Francisco: Ignatius Press, 2012), 162.
  2. Augustine, “The Happy Life,” trans. Ludwig Shopp, in The Fathers of the Church, vol. 1 43-84. ed. Ludwig Shopp, et. al. (New York: CIMA Publishing Co., 1947), 47-48.
  3. John Rist, Augustine (Cambridge: Cambridge University Press, 1994), 95.
  4. Frederick Copleston, A History of Philosophy, vol. 2. (London, England: Burns Oates & Washbourne, 1950), 78.
  5. Rist, Augustine, 96.
  6. Plotinus, Ennead IV.8, trans. Barrie Fleet (Las Vegas: Parmenides Publishing, 2012), 58.
  7. Rist, Augustine, 94.
  8. Copleston, A History of Philosophy, 79.
  9. Augustine, “The Way of Life of the Catholic Church,” trans. Donald Gallagher and Idella Gallagher, in The Fathers of the Church: A New Translation, vol. 56, 1-61. ed. Roy Defarrari, et. al. (Washington, D.C.: Catholic University of America Press, 1966), 7.
  10. Rist, Augustine, 94.
  11. Augustine, “Way of Life,” 41.
  12. Augustine, The Trinity, trans. Stephen McKenna (Washington, D.C.: Catholic University of America Press, 1963), 465.
  13. Athanasius, “We Worship the Word Made Flesh,” in The Fathers of the Church, ed. Mike Aquilina (Huntington, IN: Our Sunday Visitor, 2013), 155.
  14. Eugene Portalie, A Guide to the Thought of St. Augustine (Chicago: Henry Regnery Company, 1960), 147.
  15. Rist, Augustine, 94.
  16. Michael Maher, “The Soul,” The Catholic Encyclopedia, vol. 14, 153-157. ed. Charles G. Herbermann, et. al. (New York: Robert Appleton Company, 1912), 156.
  17. Augustine, The Trinity, 464.
  18. Copleston, History of Philosophy, 79.
  19. Joseph Krylow, “It Doesn’t Concern You: An Analysis of Augustine’s Argument for the Immortality of the Soul,” American Catholic Philosophical Quarterly 88, no. 1 (2014), 50.
  20. Richard Penaskovic, “An Analysis of Saint Augustine’s De Immortalitate Animae,” Augustinian Studies 11 (1980), 175.
  21. Brian Brinzan, “The Theory of the Immortality of the Soul with Saint Augustine,” The Scientific Journal of Humanistic Studies 5, no. 9 (2013), 146.
  22. Copleston, History of Philosophy, 79.
  23. Rist, Augustine, 94.
  24. Catechism of the Catholic Church, 362.
Brother Justin Hannegan, OSB About Brother Justin Hannegan, OSB

Br. Justin Hannegan is a Benedictine monk at the Abbey of Saint Mary and Saint Louis in Creve Coeur, Missouri. He earned his undergraduate degree in philosophy from the University of Dallas, and his Master's degree in philosophy from Northern Illinois University.


  1. Jim Foley says:

    This is a valuable discussion of a much neglected subject – the soul. However, the author gives the impression that St. Augustine introduced the concept into Christianity. Actually the idea of the soul was current in late Judaism. It is implicit in the Gospels. We can see it reflected clearly in Paul’s first letter to the Thessalonians, probably the earliest of his epistles written around 52 A.D. “For God has not destined us for wrath, but to obtain salvation through our Lord Jesus Christ, who died for us so that whether we wake or sleep we might live with him. . . May the God of peace himself sanctify you wholly; and may your spirit and soul and body be kept sound and blameless at the coming of our Lord Jesus Christ.”

    • Tonquedec says:

      Please indicate where the author gives that impression? I didn’t find that insinuation at all.

  2. Jim Foley says:

    The title of the article is “How Augustine Made Us More than Matter—and Immortal” which clearly implies that Augustine introduced the idea of an immortal soul. Further, the author states: “In this article, I retrace the steps that led him to his developed understanding of the soul—an understanding that would shape subsequent Catholic teaching.” Actually what the Confessions give us is the tale of one man’s emergence from Manichaeism through Neo-platonism. Remember Augustine died in the 5th century A.D. However, if we read Lactantius or Athanasius of Alexandria a century earlier, we find similar arguments for an immortal, spiritual soul.

  3. Martin B. Drew says:

    Brother Hannegan here is a clear article on man and his existence. and life. In the beginning of the article the impression is given by showing the existence of materialism which eliminates the soul. But each man not only moves but uses those faculties of intellect and will l to choose good or evil or indifferent acts. Augustine discovered that. not only logically but from Imago Dei and eternal salvation.