What does it mean to be an adult? For Augustine, this question is not simply about reaching a particular age or stage in life. Instead, it touches the very core of his spiritual and philosophical journey. For him, true adulthood is marked by a process of inner formation, a journey from youthful instability to the full stature of a spiritually mature person.
This journey, as Augustine presents it in Confessions, is less about biology and more about the shaping of one’s inner life.
The forming of a mature self
Augustine’s understanding of adulthood is deeply connected to his notion of formatio — the process of being made whole, upright, and fully formed. This is not necessarily a physical or psychological maturation, but a primarily spiritual one.
In fact, Augustine often uses the image of being “made erect” (factius erectior, fully upright, properly human) to describe his own journey to maturity, drawing on the Latin word grandius to convey not just the idea of physical growth, but the emergence of a somewhat heroic, “grand,” spiritually mature self.
This movement toward maturity is, for Augustine, a continuous process. It is not a one-time event, but a series of rebirths — a constant turning away from the distractions of the world toward the stability of the divine.
This idea is beautifully captured in Augustine’s constant references to water and baths, from the public baths in his native Tagaste to the baptismal pool. It is in these scenarios (the public baths) where Augustine claims he first experienced the stirrings of adulthood – and adult desire, even. Later, in the baptismal waters, he finds a more complete and lasting transformation.
Standing upright: From weakness to fullness
Augustine’s language around adulthood often contrasts weakness and strength, flaccidity and fullness. For him, becoming an adult means standing upright in the fullest sense, both physically and spiritually. This is reflected in the famous scene where his father, seeing the physical signs of Augustine’s maturation in the baths of Tagaste, rejoices at the thought of having grandchildren. But this “fertile adulthood,” as he puts it, is not the one Augustine ultimately seeks. Instead, he looks to the spiritual maturation marked by his later baptism — a more profound standing upright, free from the burdens of youthful lust and confusion.
Feeding the mature soul
Augustine’s adulthood is also marked by a change in appetite, moving from the “milk” of childish teachings to the “solid food” of mature spiritual understanding. This shift is vividly illustrated in Confessions, where he describes his philosophical journey as a process of learning to distinguish nourishing food from mere junk, the substantial from the superficial.
This is not at all a matter of dietary preferences, but a profound existential shift — a movement from being driven by base desires to a life animated by higher, more permanent things.
In Latin, adultus is related to the verb adolescere, meaning “to grow up,” but it also draws from alere, which means “to nourish” or “to feed.” The passive suffix tus indicates a state of having been fed or nourished to maturity. An adultus is, in this sense, not just someone who has grown up, but someone who can feed themselves.
This stands in contrast to the term infans, which literally means “unable to speak” and, by extension, unable to feed oneself. In more ways than one, it is all related to what one can do with one’s mouth – either feeding or speaking properly.
Augustine plays with this etymology in Confessions, emphasizing the importance of moving from spiritual infancy, a state of dependence and immaturity, to spiritual adulthood, a state of self-sustenance and mature understanding. It is a journey from being fed to becoming the one who feeds, both in the physical and spiritual senses.
The inner human as the measure of maturity
Finally, Augustine ties adulthood to his concept of the inner human — a self that persists through the many transformations of life, always seeking a deeper, more stable form of existence. This inner self is a psychological state, yes, but it is also the very core of a person’s being: the seat of memory and desire, the place where true maturity takes root.
In sum, adulthood for Augustine is not a static state but an ongoing process of being made grandius — greater, fuller, more complete. It is a journey from distraction to focus, from dispersal to unity, from mere existence to true life. For Augustine, to be an adult is to stand upright in the fullest sense, rooted in the love and knowledge of God.
