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On Knowledge:  Augustine and Aquinas

Kyle Sanders

The thoughts of St. Augustine of Hippo and St. Thomas Aquinas can be compared to Raphael’s painting The School of Athens, each doctor imitating the gestures of their philosophical heroes, Plato and Aristotle.  Augustine is pointing up to the heavens, and Aquinas gesturing toward the earth.  This is particularly true with their respective epistemologies.  However, their thoughts interweave as well.  There are both similarities and differences within the epistemologies of Augustine and Aquinas. 

            The first similarity is their description of an ascent of the soul that moves from reason to beyond reason, known to most as a mystical experience.  Augustine, of course, draws this image from Plotinus’ ascent of the soul.  For Augustine the soul takes seven steps to ascend to greater knowledge.  The first knowledge is “of the body”[1] in which the soul contemplates the body, and focuses its attention on it.  The second knowledge is “through the body” in which the body is able to sense and discern with greater clarity its surroundings.  The third knowledge is “about the body.” This is knowledge that goes beyond the sensory memory of the previous degree; it’s an occupational (farming, cooking, and being bi-lingual) knowledge.  The fourth knowledge is “toward itself;” it is here that the soul turns in on itself contemplating something closer to God.  The fifth knowledge is “in itself;” contemplating itself purely, without the stain of sin, the soul moves closer to that contemplation of truth, namely God.  The sixth knowledge is “toward God.”  It is not enough for the soul to be free of stain; it must look towards something that is greater than itself, mainly those trascendentals, truth, good, and beauty.  The final knowledge is “in God” this is the mystical knowledge, the knowledge that succeeds that of reason.[2]  The knowledge moves from corporeal things, to incorporeal things, to the incorporeal thing, namely God.

            Aquinas had the same sort of idea.  First, there must be the knowledge and understanding of things on this earth, the physical, before the philosopher can move to something incorporeal.  This is mostly because one gains knowledge through the senses—this is a subject that will be discussed later, however, it must be revealed at this point in time.  After this knowledge, one would put down reason, as if it were a hat, to more fully know the divine.  “Moreover, philosophical knowledge of God, though genuine is extremely limited.”[3]  More blatantly put, one must have a mystical experience.  “Finally, knowledge about God, whether philosophical or theological, is subordinate and teleologically orientated to the experimental knowledge of God, knowledge by acquaintance, which is attainable, imperfectly in mystical states, perfectly in the vision of God in heaven.”[4]  For both Augustine and Aquinas one must move from reason to something beyond reason, namely the mystical, to know God more fully.

            They both agree that knowledge of God is not found from the senses.  However, the senses themselves are treated very differently by each.  Augustine has a negative view of the senses.  He does not think knowledge can come from them because they never provide a stable knowledge.  Everything the senses perceive is ever-changing.  “Through Plotinus he early understood that pure sensism leads inevitably to universal doubt; if reality is in the end reducible to sensible appearance, then, since this is in a state of perpetual flux and self-contradiction, no kind of certitude will any longer be possible.”[5]  He doubts that truth can even be conferred from the senses.  “From our corporeal senses, then, no genuine truth is to be looked for.”[6]  He also says that sense knowledge is not lasting which in turn questions the validity of the senses as vessels of which to perceive truth.  “Moreover, all that I contact with a bodily sense, such as this sky and this earth and whatever I perceive to be in them, I do not know how long it will last.  But seven and three make ten not only now but always.”[7]  In other words, things perceived not by the senses but by the mind are more able to discern and know truth.  To Augustine, one comes to knowledge of the truth through the mind not senses. 

            Aquinas, in the Aristotelian tradition, sticks to the senses.  To him the senses are that by which we perceive truth.  This is in part because of his hylomorphism, which is the essence of a being is both form and matter.  Because the form and matter are united, and not divided as in Platonic tradition, and by philosophical heritage Augustinian, a human soul/mind knows truths through the body, to which senses adhere.  “By means of the senses we directly grasp the things we know, thanks to our perception of their sensible qualities.”[8]  It is by our senses that we know.  The mind knows of other things through the senses.  George knows a car because he sensed that car.  He saw it; he smelled it; he even touched it.  The knowledge of car was not his a priori but was sensed.  “For Aquinas the mind is initially a capacity for knowing; and, as far as the natural order of things is concerned at any rate, it cannot come to know anything except through or in dependence on experience, the primary form of experience being sense-experience or sense-perception.”[9]  Again, knowledge comes from the experience of the senses not solely from the mind.

For Aquinas sensing is how we come to knowledge.  Augustine has different idea.  Augustine says that we come to know through divine illumination of ideas in the memory.  “We ought rather to believe that the nature of the intellectual mind was so made that, by being naturally subject to the intelligible realities, according to the arrangement of the creator, it see these truths in a certain incorporeal light of a unique kind, just as the eye of the body see the things all around it in this corporeal light.”[10]  One’s knowledge is illumined by the light of God.  Much like a flashlight or a candle illumines a dark house without electricity.  “It is clear that in his opinion the human mind needs a divine illumination to apprehend truths which in some sense transcend it or are superior to it and thus exceed its capacity when it is left to itself.”[11]  Truths are beyond the weak human intellect.  The human necessarily needs divine illumination to grow in knowledge; he cannot do it himself.  This idea fits in well with Augustine’s whole thought of the weakness of humanity.  To clarify, this illumination does not inhibit free will.  Each man chooses to “see the light” or not “see the light.”  “The divine illumination makes visible to the mind the elements of immutability, necessity and unchangeability in eternal truths, though it does not follow that we actually see the divine activity.”[12]  Men must have “an eye fit to see”[13] the illuminated ideas, but that does not necessarily show that the illumination is divine.  Augustine held firmly to this theory of divine illumination, but “As for the theory of divine illumination, it was given a minimizing interpretation by Aquinas.”[14]

Aquinas’ idea of knowledge began with the senses.  One senses another being and in turn comes to knowledge that he himself knows.  “No one perceives that he understands except from this that he understands something: because he must first know something before he knows that he knows; and the consequence is that the mind comes to actually know itself through that which it understands or senses,”[15] and, “It is by knowing something that we know that we know.”[16]  One comes to know himself through the revelation that he knows something else.  This is where knowledge buds.  Every other genus of knowledge directly comes from this first deduction as a knower.  However, one takes this knowledge, that of being a knower, and directs it towards things outside of himself.  “Indeed, he observes that the direct and immediate object of our knowledge is not our knowledge, but physical things existing outside our knowledge.”[17]  Material things, though, are not the only objects of the intellect.  One experiences material things through the senses and then abstracts in the mind.  “In saying that the proper object of the intellect is that which the things is (proprium objectum intellectus quod quid est) Thomas has provided a simple and exhaustive explanation for the tendency, so obvious in the human mind, to turn all its objects into abstract essences.”[18]  The dynamism of the intellect moves also to incorporeal things—these are less knowable because they cannot be sensed.  “Although, Thomas insists, the primary objects of human knowledge are material things, the mind is not limited to them in its potential field of knowledge.”[19]  For Aquinas, knowledge is directed material things, although the only direction the mind can take.  Overall, though, Aquinas’ knowledge is dependent not upon divine illumination but upon the senses.

            As the ascent of the soul earlier in the essay hinted at, the ultimate knowledge is that of God.  Because man is creation, he cannot know God fully.  If he did, he would be equal to God which is not possible in the Christian metaphysical systems.  Both Augustine and Aquinas hold this position.  Aquinas said, “Almost the whole of philosophy is directed toward the knowledge of God.”[20]  For Augustine, once man comes to know himself, he is ready to know God.  “To know oneself means to know God, and know the self as God knows it, for from Him nothing can be hidden.  In this self-knowledge can man truly ‘confess,’ to God in silence which ‘cries aloud with love,’ a cry expressed not with ‘bodily words and sounds but with words uttered by the soul.”[21]  To know God is the ultimate knowledge of the philosopher.

            Augustine and Aquinas have some similarities within their different ideas of knowledge.  Both present an ascent which starts with reason and ends in a mystical experience.  This is where they separate though.  Augustine discounts the senses as not being sources of knowledge while Aquinas bases his whole epistemology on the senses.  Augustine claims that one comes to know through divine illumination.  Aquinas claims that one comes to know through the senses.  However one attains knowledge, knowledge of God is the end and final thought. 

Work Cited

1.      Augustine of Hippo. The Greatness of the Soul and The Teacher. trans. Joseph Colleran,

Westminster, Maryland: Newman Press, 1950.

2.      Augustine: Earlier Writings. ed. John Burleigh, Philadelphia: The Westminster Press,

1953.

3.      Copleston, F.C. A History of Medieval Philosophy. Notre Dame, Indiana: University of

Notre Dame Press, 1972.

4.      Gilson, Etienne. Elements of Christian Philosophy. Garden City, New York: Doubleday,

1960.

5.      Gilson, Etienne. The Spirit of Medieval Philosophy.  Trans. A.H.C. Downes, NY: Charles

Scribner’s Sons, 1940.

6.      Gilson, Etienne.  Thomist Realism and the Critique of Knowledge. San Francisco:

Ignatius Press, 1986.

7.      O’Connell, Robert. St, Augustine’s Confessions the Odyssey of Soul. Cambridge, Mass:

Belknap Press, 1969.

8.      Piefer, John Fredrick. The Concept in Thomism. NYC: Bookman Associates, 1952.