In St Augustine’s (354-430 AD) analysis, there are three different external sources from where the Human Soul can receive impulses and information leading to the Truth:

1. a psychical object in the external world accessed through the 5 senses
2. Teacher, through signs (e.g., spoken or written textual teachings, testimonies, revelations – like the Bible)
3. God through illumination

The 1st source exists in the sensible/physical, while the 2nd and 3rd is in the intelligible/spiritual realm.

According to the standard (but maybe simplistic view – see “Augustine on the Varieties of Understanding and Why There is No Learning from Words”) Augustine sustains, that information transmitted with signs by a trustworthy Teacher (like textual information) is not enough for a true understanding; Sense perception and/or illumination is also needed to attain it.

It is noteworthy the presence of the stoic assent [2.2.1] and the importance of free will [2.8.6] in this structure (see UML Use Case diagram below).

Use cases:

Faculty, Power	Use Case	Relations
5 senses: HEAR, SEE, SMELL, TASTE, TOUCH	Use SEE, HEAR, SEE, SMELL, TASTE, TOUCH perception (UC1-UC5): Senses are hierarchical: “The criteria governing the hierarchy are the relative publicity of the object of the cognitive capacity, the reliability of the capacity and its object , and, corresponding to both of these, the relative degree of immateriality and immutability of the object. Relying upon the criterion of relative publicity, Augustine begins by noting that even among the senses there is a hierarchy of sorts, for vision and hearing seem considerably less private than both smell and taste, wherein part of the object must actually be taken into one’s body and consumed during the process. Likewise, it seems possible to see or hear the same object at the same time. In between these two extremes is the sense of touch, since two individuals can touch the same part of an object, but not at the same time. Augustine also emphasizes the fact that even in sight and hearing, the most public of the senses, one’s relation to the object is always perspectival. For example, one’s visual or aural relation to the object imposes limits upon how many others can have a similar relation, as well as the nature of the relation they can have. Thus, sense experience, in addition to relating to objects that are material, mutable, and hence ultimately unreliable, is also intractably private.” (Mendelson, 2018)
INNER SENSE	Senses coordinated by INNER SENSE (sensus interior) (UC6): “The inner sense… makes us aware that the disparate information converging upon us from our various senses comes from a common external source (e.g., the smell and taste belong to the same object one is looking at while holding it in one’s hand). The inner sense also makes us aware when one of the senses is not functioning properly. In both of these respects, the inner sense bears an organizational and criterial relation to the senses, not only combining the information of the senses, but passing judgment on the results of this synthesis.” (Mendelson, 2018)	includes UC1-UC5
REASON (ratio)	Use REASON (Ratio) to access Knowledge (Sciencia) and Truth (UC7): Reason is the highest function of Soul, co-ordinates the subordinated faculties, provides deductive, logical thinking and access to Knowledge and Truth. “two functions of the mind are distinguished: contemplating truth as the source of true judgments (sapientia) and the rational activity of knowing and managing temporal affairs (scientia). One might interpret this as the current distinction between the theoretical and the practical intellect. God’s image is in the contemplative mind, for only this, as wisdom, lasts forever. The act of faith belongs to the rational (practical) mind, which focuses on the temporal Christ, his life, words, death, and resurrection. Human beings ascend from knowledge (scientia) in this temporal life to wisdom (sapientia) in eternal life where God is contemplated.” (Teske, 2003)	includes UC6, UC8, UC9, UC10, UC11, UC13
REASON (ratio)	UNDERSTANDING (scire, intellegere) concepts (UC8): is cognitive state characterized posession and autonomuous usage of concepts. “Augustine thinks of understanding rather than justification as the differentiating ingredient of knowledge, the main thesis of the De Magistro, that no man can teach another knowledge (scientia), can now be glossed as the claim that no man can teach another to understand something. The argument will not be that information cannot be transmitted from one person to another, but that the appreciation or understanding of any such information is a task that each person must work at for himself.” (Burnyeat, 2018)
REASON (ratio)	Deductive reasoning (UC9): “Augustine seems to think of ‘reason’ as strict demonstration, perhaps as a simply deductive process” (Teske, 2003)
MEMORY	Use MEMORY to store/recollect images and ideas (UC10): “Augustine holds that the things which memory remembers can be entirely in the past or still existing in the present; that the memory of those things which always exist, such as eternity itself, requires no imagery; and that, though such things which always exist are present, the intellectual vision of them is past – a vision from which we have flowed down so that we have begun to see other things – that is, sensible things – in another way: that is, through the senses.” (Teske, 2003)
IMAGINATION	Use IMAGINATION to form images based on senese perception and signs transmitted by the “Witness” (UC11): “Thus he can say that just as images are the objects of the vision of imagination (what he sometimes calls “spiritual vision”) so the bodies themselves (“ipsa corpora”) are what we see in bodily vision” (Teske, 2003)
BELIEF	Form justified true BELIEF based on trust on the “Witness” (UC12): “Augustine thinks that true knowledge requires first-hand acquaintance; second-hand information, e.g., from reliable testimony, may yield true and even justifiable belief, but not knowledge in the strict sense. […]  The later Augustine, in a more generous way of speaking, widens the term “knowledge” (scientia, to be distinguished from “wisdom”, sapientia) so as to include what we learn through sense perception and from reliable witnesses“. (Tornau , 2020)	extends UC11 if there is trust in Witness
ILLUMINATION	Precieve intelligible realities through ILLUMINATION (UC13): The Soul through Illumination precieves intelligible realities presented by God. “Augustine uses an analogy as old as Plato according towhich the mind’s relation to intelligible objects is like the relation of the senses to sensible objects… Illumination is… something that is available to all rational minds, the atheistic mathematician as well as the pious farmer measuring a field.” (Tornau, 2020)
WILL	Exercise free WILL to initiate action (UC14): “Like desires, first-order volitions are intentional or object-directed and operate on all levels of the soul. Like memory and thought, will is a constitutive element of the mind. It is closely related to love and, accordingly, the locus of moral evaluation. We act well or badly if and only if our actions spring from a good or evil will, which is equivalent to saying that they are motivated by right (i.e., God-directed) or perverse (i.e., self-directed) love (De civitate dei 14.7). “As in Stoicism, the will to act is triggered by an impression generated by an external object (visum). To this the mind responds with an appetitive motion that urges us to pursue or to avoid the object (e.g., delight or fear). But only when we give our inner consent [assent] to this impulse or withhold it, does a will emerge that, circumstances permitting, results in a corresponding action. […] The mechanics of the will in Augustine’s moral psychology is strongly indebted to the Stoic theory of assent [to impulse], which it however modifies in at least one respect” (Tornau , 2020)	extends UC7 if assent is given; includes UC15
LOVE	Use Love e.g. for Truth, Itself etc..(UC15)

Actors:

ACTOR	DESCRIPTION	RELATIONS
Object in External World	A material object in the external world.	in relation with UC1-UC5
User of soul	A human person.	uses UC7, UC14
God	The Christian God	in relation with UC13
Witness	A human person testifying, teaching	uses UC1-UC2

Sources:

• Burnyeat, Myles, “Wittgenstein and Augustine De Magistro” Proceedings of the Aristotelian Society 61 (1987), 1–24.
• King, Peter, “Augustine on the Impossibility of Teaching” in Metaphilosophy” 29 (1998), 179–195
• Teske, Roland “Augustine’s theory of soul” in The Cambridge companion to Augustine, Eleonore Stump and Norman Kretzmann (ed.), Cambridge University Press, 2003
• Tornau, Christian, “Saint Augustine”, The Stanford Encyclopedia of Philosophy (Summer 2020 Edition), Edward N. Zalta (ed.), The Stanford Encyclopedia of Philosophy (Winter 2020 Edition), Edward N. Zalta (ed.)
• Nawar, Tamer, “Augustine on the Varieties of Understanding and Why There is No Learning from Words”, Oxford Studies in Medieval Philosophy, Volume 3, (2015)
• William P. O’Connor, “The Concept of the Human Soul according to Saint Augustine”, Dissertation 1921, Catholic University of America

First published: 23/5/2019
Updated: 10/5/2021