Saint Augustine
The Doctrine of Divine Illumination

"Le point de départ de la philosophie augustinien:  Preuve noologique de l'existence de Dieu"

    Like Plato, Augustine considered intelligible truth the best safeguard there was against scepticism.  His doctrine of the divine illumination always remained for him the decisive moment in his own liberation from scepticism.

    The soul is the cause of its intellectual cognitions.  Yet, on this point, Augustine has often stressed the fact that there is more in intellectual knowledge than in either the thing or the mind.  Fully rational knowledge is true knowledge.  Now, true knowledge exhibits certain characters which are both distinct and intimately related.  Truth is necessary: whether we say that seven plus three are ten, or that wisdom is a knowledge that confers beatitude upon those who possess it, we do not simply know that it is so; we say that it cannot be otherwise.  Since truth is necessary, it is immutable, for indeed that which cannot be other than it is, cannot possibly change.  Thirdly, since truth is immutable, it is eternal, because that which cannot change cannot cease to be.  Now, where could our mind discover these characters of truth?  Not in things, for all of them are contingent and, since they all begin and end in time, none of them is either immutable or eternal.  Nor can our mind discover these characters  in itself, since, like all created things, it is contingent, mutable and enduring in time.  The only way to account for these characters of truth in the human mind is to admit that, every time it forms a true judgment, our mind is so to speak in contact with something that is immutable and eternal.  But to say "immutable" and "eternal" is tantamount to saying God.  The existence of immutable truths in mutable minds is the proof of the existence of God.  In other words, the demonstration of God's existence can be considered as included in the epistemology of Saint Augustine.

    This proof is confirmed by the common nature of truth.  All minds can see the same truth in the same way.  Now, since I cannot see it in the mind of any other man, nor make any other man see it in my own mind, there must be a cause which makes us all see it at the same time and in the same way.  God is the inner master who teaches the same truth to all the minds that seek after it.  He is, so to say, the Intelligible Sun which enlightens the minds of all men.  Those who turn away from sensations and purify their souls from vices can raise their minds up to contemplation of truth that is a sort of intellectual contact with God, but even in the simplest judgment, provided only it be a true one, there is a sufficient foundation for a proof of the existence of God.  However different in their details, all the Augustinian itineraries of the soul in quest of God are substantially the same:  they go from the exterior to the interior, and from the inferior to the superior; ab exterioribus as interiora, ab inferioribus as superiora.


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    We cannot, says Augustine, perceive the immutable truth of things unless they are illuminated as by a sun.  This divine light, which illumines the mind, comes from God, who is the 'intelligible light', in whom and through whom all those things which are luminous to the intellect become luminous.  In this doctrine of light, common to the Augustinian School, Augustine makes use of a neo-Platonic theme which goes back to Plato's comparison of the Idea of the Good with the sun,  the Idea of the Good irradiating the subordinate intelligible objects or Ideas.  For Plotinus the One or God is the sun, the transcendent light.  The use of the light-metaphor, however, does not by itself tell us very clearly what Augustine meant.  Happily we have to help us such texts as the passage of the De Trinitate where the Saint says that the nature of the mind is such that, 'when directed to intelligible things in the natural order, according to the disposition of the Creator, it sees them in a certain incorporeal light which is sui generis, just as the corporeal eye sees adjacent objects in the corporeal light'.  These words seem to show that the illumination in question is a spiritual illumination which performs the same function for the objects of the mind as the sun's light performs for the objects of the eye: in other words, as the sunlight makes corporeal things visible to the eye, so the divine illumination makes the eternal truths visible to the mind.  From this it would appear to follow that it is not the illumination itself which is seen by the mind, nor the intelligible Sun, God, but that the characteristics of necessity and eternity in the necessary and eternal truths are made visible to the mind by the activity of God.  This is certainly not an ontologistic theory.

    But why did St. Augustine postulate such an illumination; why did he think it necessary?  Because the human mind is changeable and temporal, so that what is unchangeable and eternal transcends it and seems to be beyond its capacity.  'When the human mind knows and loves itself, it does not know and love anything immutable,' and if truth 'were equal to our minds, it also would be mutable', for our minds see the truth, now more now less, and by this very fact show themselves to be mutable.  In fact, truth is neither inferior nor equal to our minds, but 'superior and more excellent'.  We need, therefore, a divine illumination, in order to enable us to apprehend what transcends our minds, 'for no creature, howsoever rational and intellectual, is lighted of itself, but is lighted by participation of eternal Truth'.  God hath created man's mind rational and intellectual, whereby he may take in His light. . . and He so enlighteneth it of Himself, that not only those things which are displayed by the truth, but even truth itself may be perceived by the mind's eye.'  This light shines upon the truths and renders visible to the mutable and temporal human mind their characteristics of changelessness and eternity.

    That the divine illumination is something imparted and sui generis is explicitly stated by St. Augustine, as we have seen.  It hardly seems possible, therefore, to reduce the illumination-theory to nothing more than a statement of the truth that God conserves and creates the human intellect and that the natural light of the intellect is a participated light.  Thomists who wish to show St. Augustine the same reverence that St. Thomas showed him, are naturally reluctant to admit a radical difference of opinion between the two great theologians and philosophers and are inclined to interpret St. Augustine in a way that would attenuate the difference between his thought and that of St. Thomas; but St. Augustine most emphatically did not mean by 'light' the intellect itself or its activity, even with the ordinary concurrence of God, since it is precisely because of the deficiencies of the human intellect that he postulated the existence and activity of the divine illumination.  To say that St. Augustine was wrong in postulating a special divine illumination and that St. Thomas was right in denying the necessity of such an illumination is an understandable attitude; but it seems to be carrying conciliation too far, if one attempts to maintain that both thinkers were saying the same thing, even if one affirms that St. Thomas was saying clearly and unambiguously what St. Augustine had said obscurely and with the aid of a metaphor.

    I have already indicated that I accept the interpretation of Augustine's thought, according to which the function of the divine illumination is to render visible to the mind the element of necessity in the eternal truths, and that I reject the ontologistic interpretation in any form.  This rejection obviously involves the rejection of the view that according to Augustine the mind beholds directly the idea of beauty, for example, as it is in God; but I am also unwilling to accept the view that according to Augustine God actually infuses the idea of beauty or any other normative idea (i.e. in reference to which we make comparative judgments of degree, such as that this object is more beautiful than that, this action juster than that, etc.) ready-made into the mind.  This extreme ideogenetic view would make the function of divine illumination that of a kind of separate active intellect: in fact, God would Himself be an ontologically separate active intellect which infuses ideas into the human mind without any part being played by the human sensibility or intellect other than the mind's purely passive role.  (This reference to an active intellect is not, of course, meant to imply that Augustine thought or spoke in terms of the Aristotelian psychology.)  It does not seem to me that such an interpretation, although doubtless much can be said for it, is altogether satisfactory.  According to St. Augustine, the activity of the divine illumination in regard to the mind is analogous to the function of the sun's light in regard to vision, and though the sunlight renders corporeal objects visible, Augustine certainly did not think of it as creating images of the objects in the human subject.  Again, although the divine illumination takes the place in Augustine's thought of reminiscence in the Platonic philosophy, so that the illumination would seem to fulfil some ideogenetic function, it must be remembered that Augustine's problem is one concerning certitude, not one concerning the content of our concepts or ideas:  it concerns far more the form of the certain judgment and the form of the normative idea than the actual content of the judgment or the idea.  In the De Trinitate Augustine remarks that the mind 'gathers the knowledge of corporeal things through the senses of the body, and, so far as he deals at all with the formation of the concept, he would seem to consider that the human mind discerns the intelligible in the sensible, performing what is in some way at least equivalent to abstraction.  But when it comes to discerning that a corporeal thing is, for example, more or less beautiful, to judging the object according to a changeless standard, the mind judges under the light of the regulative action of the eternal Idea, which is not itself visible to the mind.  Beauty itself illuminates the mind's activity in such a way that it can discern the greater or less approximation of the object to the standard, though the mind does not behold Beauty itself directly.  It is in this sense that the illumination of Augustine does not clearly indicate how we obtain the notions of seven and three and ten, the function of illumination is not to infuse the notions of these numbers but so to illuminate the judgment that seven and three make ten that we discern the necessity and eternity of the judgment.  From a passage already referred to, as from other passages, it seems to follow that, while we obtain the concept of corporeal objects, a horse, for example, in dependence on the senses, and of an immaterial object like the soul through self-consciousness and interpretation, our certain judgments concerning these objects are made in the light of 'illumination' under the regulative action of the eternal Ideas.  If the illumination has an ideogenetic function, as I believe it to have in Augustine's view, then this function has reference not to the content of the concept, as if it infused that content, but to the quality of our judgment concerning the concept or to our discernment of a character in the object, its relation to the norm or standard, which is not contained in the bare notion of the thing.  If this is so, then the difference between St. Augustine and St. Thomas does not so much consist in their respective attitudes towards abstraction (since, whether St. Augustine explicitly says so or not, his view, as interpreted above, would at least demand abstraction in some form) as in the fact that Augustine thought it necessary to postulate a special illuminative action of God, beyond His creative and conserving activity, in the mind's realisation of eternal and necessary truths, whereas St. Thomas did not.

    On this view of illumination one can understand how it was that St. Augustine regarded the qualities of necessity and unchangeability in the eternal truths as constituting a proof of God's existence, whereas it would be inexplicable on the ontological interpretation, since, if the mind perceives God or the divine ideas directly, it can need no proof of God's existence.  That Augustine did not explain in detail how the content of the concept is formed, may be regrettable, but it is none the less understandable, since, though interested in psychological observation, he was interested therein, not from an academic motive, but rather from spiritual and religious motives: it was the soul's relation to God which concerned him primarily and, while the necessity and unchangeability of the eternal truths (as contrasted with the contingency and changeability of the human mind) and the doctrine of illumination helped to set this relation in a clear light and to stimulate the soul in its Godward direction, an investigation concerning the formation of the concept as such would not have had such a clear relation to the Noverim me, noverim Te.

    To sum up.  Augustine asks himself the question: How is it that we attain knowledge of truths which are necessary, immutable and eternal?  That we do attain such knowledge is clear to him from experience.  We cannot gain such knowledge simply from sense-experience since corporeal objects are contingent, changeable and temporal.  Nor can we produce the truths from our minds, which are also contingent and changeable.  Moreover, such truths rule and dominate our minds, impose themselves upon our minds, and they would not do this if they depended on us.  It follows that we are enabled to perceive such truths under the action of the Being who alone is necessary, changeless and eternal, God.  God is like the sun which illuminates our minds or a master who teaches us.  At this point the difficulty in interpretation begins.  The present writer inclines to the interpretation that, while the content of our concepts of corporeal objects is derived from sense-experience and reflection thereon, the regulative influence of the divine ideas (which means the influence of God) enables man to see the relation of created things to eternal super-sensible realities, of which there is no direct vision in this life, and that God's light enables the mind to discern the elements of necessity, immutability and eternity in that relation between concepts which is expressed in the necessary judgment.  Owing, however, to St. Augustine's use of metaphor and to the fact that he was not primarily interested in giving a systematic and carefully defined 'scholastic' account of the process of knowledge, it does not seem possible to obtain a definitive interpretation of his thought which would adequately explain all the statements he made.

(HISTORY OF PHILOSOPHY: Mediaeval Philosophy; Copleston, Frederick, S.J.; NY; 1962)