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Augustine's Theory of Illumination and Divine Ideas

I want to approach the doctrine of illumination from two points of view: (1) First, as a general claim, that illumination - or something like Platonic reminiscence - is required for all our knowledge. Here we will have to ask whether this "knowledge" is supposed to include the contents of our ideas or concepts, the rules in terms of which we form judgments, or both. (2)Second, I want to investigate the special claim that illumination is required for some kinds of knowledge - even if not for all. And again, we will have to ask whether we are talking aboutcertain ideas or concepts, or whether we are talking about the way we put ideas or concepts together to form judgments - or both.

I want to make this distinction because in the thirteenth century, Thomas Aquinas and John Duns Scotus argue that illumination, as traditionally conceived, is not necessary. (The do keep the term, but that's all; in fact, they have rejected the doctrine.) Now, what they are really arguing against is claim (1). That is, they are arguing against the claim that we always need some kind of illumination, in every instance of knowing. We must then ask: If, in addition to the general claim (1), there are other considerations that seem to require illumination in certain cases and for certain instances of knowledge, then do the arguments by Aquinas and Scotus against the general claim (1) speak also to this weaker claim - that is, to (2)? In short, is the wholesale rejection of illumination by Aquinas and Scotus really justified and well argued for? Or do there remain reasons why illumination might still be needed in certain cases?

The General Theory of Illumination

Let us now look at the general theory of illumination, which is what I will call claim (1) above, that illumination is always needed.

Why did Plato think his doctrine of reminiscence was needed? Well, let me set up a kind of argument:

(1) Knowledge worthy of the name is fixed, immutable. Here we have an ideal notion of knowledge, knowledge as a kind of limit. This is a kind of implicit premise of the whole discussion.

(2) Hence, Plato thinks, the objects of knowledge must be fixed and immutable too. They must be ideal things - that is, the Forms. That is why Plato talks so much about mathematics and values, where we conspicuously encounter idealized notions, standards. (Let us not worry too much here about the basis for the inference from (1) to (2). That will come later.)

(3) Now we have a kind of premise, a Principle of Acquaintance: We form knowledge of and only of those things with which we are directly acquainted - the things we come into direct contact with. Note the formulation `We form'. Knowledge is something we produce. It is the product of our act. (This, of course, does not mean that the object of knowledge is a product of our act.) Now I am not sure I can find this premise explicitly in Plato, but it will be all right for us to use it in setting out the present argument, because it is on exactly this point that there will be a big difference between Plato's theory and Augustine's. Therefore, let's call the principle "Platonic" in that very convenient loose sense of the term. In any case,

(4) From (2) and (3), it follows that we must have at some time come into direct contact with the Forms, since we do have knowledge. But we have not come into contact with them in this life. Things in this life unfortunately fall conspicuously short of the ideal. We simply don't encounter any ideally perfect circles or perfectly just persons in this life. Hence - and this follows quite rigorously - we encountered those ideals before this life, and we are only now remembering them.

This is roughly the basis for the famous doctrine of reminiscence. Now let's look at Aristotle. He will be important, since Aquinas and Scotus in the thirteenth century will be arguing against illumination on basically Aristotelian grounds.

Aristotle accepts (1) and part of (2). The objects of knowledge are immutable and in some sense eternal. But Aristotle doesn't think it follows that they must be ideal limits - idealized things like geometrical points, perfect circles, perfectly just people. Thus, Aristotle rejects part of Plato's move from (1) to (2). For Aristotle, an idealized notion of knowledge does not imply that its objects must be idealizations. (On the other hand, Aristotle will accept (3), at least for the most basic kinds of knowledge.) Hence, for Aristotle there is no need for reminiscence in general. Step (4) does not follow. The thirteenth - century Aristotelians like Aquinas and Scotus are going to conclude likewise that there is no need for illumination in general.

But - and this is always an embarrassing problem for Aristotelians - even if the objects of knowledge need not be ideal in all cases, still some of them are ideals - perfect circles, perfectly just states, and the like. What about the knowledge of them? In such cases, it seems, the missing part of step (2) is restored, and the argument goes through. If reminiscence is not needed in general, it looks as if it is still going to be needed in special cases.

Aristotle and his followers have really very little to say here. I find it astonishing how bad the Aristotelians are on this point. Their account of mathematical knowledge, for instance, seems to me to be very weak. And in fact, mathematicians historically have always been Platonists in spirit. So in short, there may still be a need for reminiscence (or illumination, or something similar) in some cases, even if not in all.

What then does Augustine do in this situation. Well first, he accepts steps (1) and (2) of the Platonic argument above. Any knowledge worthy of the name (we must always add this clause when dealing with the Platonic tradition) is of ideals, of standards - in short, of divine ideas. That is, for Augustine, the objects of knowledge are divine.

On the other hand, the human intellect is a creature. Therefore, on the general principle that the lower cannot act on the higher, which we've seen before, it follows that creatures cannot act on the divine ideas. Creaturely minds cannot reach up and grasp the divine ideas - grab them, as it were, and pull them down into the minds themselves - since that would be doing something to them, and would violate the hierarchical arrangement of Augustine's universe.

Hence, Augustine's principle of order and justice and his view that souls are creatures leads him to deny the Principle of Acquaintance as formulated in (3), although he will obviously have some form of a Principle of Acquaintance in virtue of his theory that the objects of real knowledge worthy of the name must be present to the mind in person.

The problem with (3) is that we don't have the power to produce in ourselves a knowledge of the only proper objects of knowledge. Hence, since we do have knowledge, it must be produced in us by something higher. That is, we don't do it; it is done to us. And that process is exactly what is called illumination.

Note that nothing less than the objects of knowledge, which are divine, can produce that knowledge in us, for basically the same reason that we cannot do it ourselves: it would involve a violation of the hierarchical order of things. Hence, illumination is done by God. No one else could do it.

How does Plato avoid this conclusion - that is, the denial of the Principle of Acquaintance as formulated in (3)? Or if not Plato himself, let's talk about those very convenient "Platonists". Well, how did Augustine get where he did? He was led to deny (3) by two principles:

(a) the principle of order and justice, the claim that the lower does not act on the higher, and

(b) the claim that souls are creatures.

(And of course the view that truth is something ideal, exalted - even perhaps divine. But we don't need to list that here, since all our authors agreed on it. Their difference lay elsewhere.)

To reject (a) would be quite foreign to the Platonic tradition. But to reject (b) isn't. There is a strong tendency in the Platonic stream to think of souls as somehow divine. Origen felt this tendency and fought against it.

What we have been talking about so far is the "General Theory of Illumination", the claim that illumination is always necessary. That view is based on a very low opinion of the human intellect. Knowledge is by rights divine. We have no right to it. If we have it nevertheless, it is a pure gift; it is in no way within our power.

The Special Theory of Illumination

Now let's turn to the special theory of illumination, the theory that, whether illumination is needed in all cases or not, it is surely needed in some cases.

Regardless of the general considerations we've just been looking at, there are also some special considerations that do not depend on Augustine's peculiar hierarchical notion of the world, or on his view that the objects of any knowledge worthy of the name are all ideals. Regardless how we stand on those two Augustinian doctrines, we seem to have certain kinds of knowledge that cannot in any case be accounted for by our own powers.

These kinds of knowledge fall into two kinds. Both kinds may be found discussed to some degree in On Free Choice of the Will, II. There are (a) certain kinds of concepts that it seems we cannot possibly produce under our own power, and (b) certain kinds of judgmental knowledge that likewise we could never arrive at under our own power.


With respect to (a), the concepts, Augustine gives an argument in On Free Choice, II, 8, that the notion of unity cannot come from the senses. (By "unity" he means simplicity, not being composed of parts.) Now we already know that, for Augustine, no ideas comes from the senses. The soul produces it within itself in response to what it sees going on in the body. And this is what isn't done in the case of the idea of unity. The attentive soul can observe most carefully what is going on in the body, but it will find no occasion there to produce an idea of unity. Hence, the idea of unity cannot come from the senses in a much stronger way than we say that for Augustine no idea comes from the senses. If we want to ask how the soul comes to have the notion of unity, we cannot turn to the senses for even part of the answer.

Theories That Won't Work

Augustine's example of unity is simply an example of an ideal or limiting notion. And, if you think about it, it is hard to see how we could possibly get any such ideal notion from the senses. Augustine's choice of unity is perhaps not the best choice he could have made to illustrate this. But consider the ideas of perfect circle or geometrical point. (I think it is easier to do this with mathematical, and in particular, geometrical concepts than it is with value-concepts.) Where on earth could we have got such ideas? Here are some theories I have heard, and here is why they won't work:

(1) Abstraction: We don't get these concepts by observing instance of them in the world around us and then abstracting out the common element. We don't do this because there simply aren't any instances of them in the observable world - no perfect circles, no geometrical points. (And even if there were geometrical points, I couldn't observe them, as this theory requires; they're too small to observe.) Strangely enough, Aquinas thinks this is the way we get such geometrical concepts. But as far as I can tell, his theory is very implausible.

(2) Negation: We don't get these concepts by negating other concepts, so to speak - that is, by starting with an idea derived by empirical means, and then mentally negating it. This theory is implausible to begin with for geometrical ideals. We do not first form the idea of an imperfect circle, or of a non-circle, and then negate it (or negate the imperfection) to get the idea of a perfect circle. How on earth could we recognize something as an imperfect circle unless we already had at least some concept of the standard it falls short of? (To have such a concept does not necessarily mean that we can articulate it very well.)

Curiously, many people seem to think this view is plausible when it comes to ideal notions like omnipotence, infinity, and the like. They think we construct a notion of omnipotence, for instance, by observing our own weaknesses and then thinking of something without those weaknesses. But, as Descartes knew (Meditation III), we cannot start from the realization that we are imperfect in certain respects and then negate that idea to form the notion of perfection in the ideal. That isn't the direction it goes. How did we come to realize we were imperfect to begin with unless we already had the notion of perfection in the ideal? How could I know about weakness, how could I know that there are things I can't do - or more appropriately for the concept of omnipotence, how could I ever come to imagine that there are things that can be done that I do not see actually being done around me - unless I somehow already had the notion of such exalted tasks? Even the word `imperfection' betrays its conceptual etymology. It is derived from the notion of perfection, not the other way around.

(3) Approximation: On this view, we don't see perfect circles or geometrical points in nature, but we do see certain approximations to them, and that is enough to give us the idea. But on the contrary, while we certainly do see approximations, that is not enough to "give us the idea" if we don't already have it. This is so even where we are not talking about ideals. If I point to a cloud in the sky and say "That looks like a camel", I must already have an idea of a camel. The cloud reminds me of a camel, but it doesn't teach me ex nihilo about camels.

(4) Convergence: This is related to (3), and is in effect an attempt to reinforce (3) with some additional considerations. On this theory, while we don't see perfect circles, we do see approximations of them, even if we don't yet have any idea what they are approximating. That is, we certainly do see lumpy circle, rough circles. Now suppose we mentally arrange these approximations in order. For instance, let us mentally arrange the approximate circles in a sequence beginning with the more lopsided and running to the less lopsided. I surely can do that! Likewise, let us arrange everything we see in order from large to small. Now, on the "convergence"-theory, the mind gets the concept of a perfect circle, and the concept of a geometric point, by thinking about these two respective sequences and taking the limit - that is, by seeing where they are headed.

But, on the contrary, taking the limit like this is not a mental operation we can take for granted. It sounds like something familiar and precise because it is a metaphor taken over from mathematics. What we are doing in the case of concept-formation is at best only "taking the limit" in a metaphorical sense. And that fact is important, because in mathematics you can frequently find a limit by certain calculations, even though you have no idea in advance how that limit is going to turn out. But it doesn't seem we can do that in the case of the kinds of limits we are talking about here. There is no "calculation" that will give us what we want. So in what other way could we ever come to see where those two sequences were heading, if we did not already have some idea of the limiting case? And for that matter (although this consideration perhaps doesn't apply to the second sequence), how do we know how to arrange our sequences to begin with? What counts in advance as a "lopsided circle", and what counts as "more" or "less" lopsided? No, the mathematical metaphor of taking limits is no help here. And don't just say, "I don't know how we do it, but we do it." That's just to say that you don't have any explanation but stubbornly refuse to admit there is a problem.

(5) Indistinguishability: On this view, although we don't see perfect circles in nature, we do see things that are perceptually indistinguishable from perfect circles. Reply: They are also perceptually indistinguishable from slightly lopsided circles. Why do we get the one concept from then and not the other? Furthermore, even if you can get this theory to work in the case of a perfect circle, it plainly will not work for geometrical points. If I can perceive something at all, it's already too big to be a geometrical point, and can be perceptually distinguished from one. Likewise, when it comes to value-concepts, the theory collapses. I don't see anything around me that is perceptually indistinguishable from a perfectly just state.

(6) Definition: On this theory, we get these ideal concepts by explicit definition, in contrast to the more or less automatic mental operations presupposed by the earlier theories. For instance, how do we define a circle - that is, a "perfect" circle, the kind of circle geometry talks about? Well,we all know the answer to that: A circle is a locus of points on a plane, equidistant from a point called the center. But look! A circle is a locus of what, on what, how distant from a what called the center? Look at all the other ideal notions that are presupposed in this definition. Of course we can define some ideal notions in terms of other ideal notions. What we want to know, however, is how this process can get started? How do we get our first ideal notion?

Now I do not mean to suggest by all this that there is no solution to the problem. But what I do want to insist on is that there is, initially at any rate, a real problem here. It is not at all obvious that any account of the origin of our ideal concepts is going to be satisfactory if we insist on getting all our concepts in one way or another from the senses. I do want to insist on the existence of the problem, even if there does turn out to be a solution to it, because those in the Aristotelian tradition are very good at overlooking this problem, or "black-boxing" it - that is, we put the sense data in the black box of the mind, and (presto!) out comes an ideal concept at the other end. There may be a name for what goes on in inside, but no real explanation.

Now, whatever else we may think of Plato's theory of reminiscence it at least has the virtue of recognizing the problem. And Augustine's theory of illumination does too. With Plato, Augustine concludes: We cannot get ideal concepts from the senses. That is what the discussion of unity was supposed to illustrate.

This then is the reasoning behind the special theory of illumination as far as concepts are concerned. There appear to be certain kinds of concepts that we cannot get through the senses. But, you may say, does it follow that we get them by illumination? That is, why is this supposed to be an argument for the theory of illumination - even as restricted to certain kinds of knowledge? Why not say we get such concepts by reminiscence or that they are just innate in us? Well, that is a good point. And perhaps while we do not need the peculiarly Augustinian themes of the soul's creaturehood and of the hierarchical structure of the world to set up the problem of ideal concepts, we might very well need them if we are going to turn these considerations into an argument for illumination in particular.

Propositions or Judgments

In any case, let us now turn to the second kind of knowledge for which there may be a special need for illumination - that is, certain kinds of propositional or judgmental knowledge. Augustine discusses this too in On Free Choice of the Will, II, and elsewhere. He talks about the rules that govern the mind. And it turns out that he means things like: "Equals added to equals are equal", "The better is to be preferred to the worse", and so on.

It is clear from his remarks that he thinks we know these rules too by illumination. Why? Simple: These rules, these truths, have two characteristics:

(1) We can know them with certainty.

(2) They are necessary, eternal, immutable.

From (1), it follows from Augustine's views on skepticism that such rules are present in person to the mind, not by proxy. That is, we do not know such truths through an innate representation of them, or by remembering them, or in any other such representative way. It is not that the ideas or thoughts of such truths are present to our mind. The truths themselves are present - or else we do not know them with certainty.

Now, since our minds are contingent, temporal, changeable things (we change our minds, for instance, forget, and so on), and since so too is the whole world revealed by sensation, it follows further from point (2) above that neither the sensory world nor the created mind can make these necessary truths present to the mind. Hence, something else is needed, and Augustine calls it illumination.

This last step does not rest on any general Augustinian considerations about ranking things according to value, or about the lower's not acting on the higher. You could argue for it that way, but you can also argue for it on the general ground: You can't build necessary structures on contingent foundations. Changeable realities are not firm enough to ground changeless truths.

While there may be a problem about the origin of our ideal concepts, it is not clear that illumination is the only solution to that problem. There are also the Platonic theory of reminiscence and the doctrine of innate ideas. But now perhaps there is a way to rule those other theories out after all, although Augustine doesn't argue this way so far as I know.

If we accept Augustine's view that the objects of real knowledge must be present to the mind in person, and not by representation, then if the ideal objects we know conceptually are somehow constituents of the eternal and necessary truths we know by propositional knowledge, then since the latter are present in person and not by representation, so too are the former. For instance, if equality itself enters into the truth "Equals added to equals are equal", then since I know that truth directly and not by representation, it would seem to follow that I know equality directly and not by representation, which would rule out both innate ideas (which are representations) and reminiscence.

Problems with the Theory of Illumination

However all that works out, let us now turn to look at some of the problems with the theory of illumination. There are a number of them.

(1) How far does Augustine mean for his doctrine to extend? One can cite conflicting texts on this point. For instance, for a relatively moderate view, there is the passage from Augustine's Retractationes. (The title Retractationes does not mean "retractions", as though Augustine is now taking it all back, but rather "retreatments".) This work was written late in Augustine's life, and is a kind of literary survey of all he had previously written. In it, Augustine takes the opportunity to correct or explain further certain things he had said in his earlier writings.

The view in the passage seems to be that illumination - here put in terms obviously meant to suggest the Meno, although Augustine makes it clear that he rejects the pre-existence of souls - is required for the more abstract sciences, but not for the so called arts, which do not deal with such exalted objects as the sciences do. For the arts, illumination is not needed. Sensation is enough.

On the other hand, for a quite strong view we can cite Epistle 120, 2, 10. According to this passage, illumination is required for every cognitive act - arts as well as sciences, even for perception.

The relative chronology of these two passages doesn't really matter. You can find texts like these throughout Augustine's writings. What this probably means is that in the end he just had no settled view about the extent of illumination. For what it is worth, my own opinion is that Augustine's more moderate view is his "better doctrine".

(2) The second problem with the theory of illumination is this: In what sense is knowledge by illumination ours? Here is how it works. In this tradition, knowledge is described in such exalted terms that it is properly an attribute of the divine. But if that is so, how then can creatures have it? And of course the obvious answer is: We can't. The truths we know by illumination (at least the ideal ones) are necessary and immutable. How then can they ever be assimilated by a contingent and changeable creature, and made its own - with or without divine illumination? In short, while something like illumination will be necessary for creaturely knowledge, how can it or anything else ever be sufficient?

The same point can be put another way: Who does the knowing? Knowledge is presumably an act of a knowing intellect. But, according to the theory of illumination, our intellect is passive and receptive in knowledge; it is the divine intellect that acts and illuminates us. So in what sense can we be said to know? God is the only one who is active here in the relevant sense.

Again, if the intellect is passive in knowledge, then how do we explain the fact that we have to work so hard at getting knowledge - of mathematics, for instance, where if anywhere illumination is needed? In other words, the theory of illumination as it stands at best needs supplementing by an account that gives some active role to the human intellect.

(3) A third problem is this: How does illumination differ from the direct vision of God, which is supposed to be reserved for the blessed in the next life - the so called "Beatific Vision"? There is a common Old Testament theme that he who looks directly on God dies. Paul says that we see now as in a glass darkly, but then (that is, in heaven) face to face (1 Cor. 13:12). How then does illumination differ from that face to face encounter with God, which is not supposed to happen in this life?

Illumination after all puts divine truths into direct contact with the human mind. We do not see them "in a glass, darkly". That would be representationalism, and spoil the whole point of the doctrine. On the other hand, the divine truths are identical with God, as we know from On Free Choice of the Will, II, and elsewhere. Hence, it looks as if illumination turns out to be a direct intellectual vision of God - the very kind of thing Augustine describes elsewhere as the ultimate goal of mankind! Ironically, therefore, despite his criticism of Varro in On the City of God, XIX, for thinking that the goal and purpose of man could be reached in this life. Augustine himself seems to be committed to saying that the goal of mankind can be attained in this life by anyone who cares to do a little mathematics or geometry. And that, I submit, is a problem. Salvation should not consist of adding a column of figures.

(4) This brings up another problem: Who gets illumined? Illumination begins to look a lot like the Beatific Vision, which is supposed to be reserved until the next life. But apart from when we are supposed to get it, such a direct vision of God is also supposed to be reserved for the blessed, the saints. Yet even the most degenerate reprobate can add two and two - an ability which requires illumination if anything does.

Later on, the problem here will be put in terms of nature vs. grace. `Grace' in this sense is a theological term that means a kind of gratuity, a divine "tip". God gives creatures some things by nature; they are built into the creatures' very structure. For instance, he gives human souls wills. But he gives some creatures more than that. He gives them supernatural things, in the etymological sense: things over and above what they get by nature. And these supernatural endowments are gratuitous: they are graces.

Given this kind of terminology, the theory of illumination makes knowledge turn out to be a super-natural grace. But super-natural knowledge - knowledge we have but nevertheless could not get under our own natural powers - is also called revelation. What else could it be? If we cannot find out for ourselves, we have to be told, and that is what revelation is. So what we see here is that the theory of illumination tends to assimilate all knowledge to revelation. But now there is an obvious problem: The heathens do not possess revelation, and yet even they can do mathematics.

The moral of the story is obviously that some new distinctions and refinements need to be made. We do not yet have a fully worked out theory of illumination. What we have in Augustine is a statement of a program. Many later authors will devote a lot of effort to straightening this all out.

Finally, there is one last thing I should mention. There is one interpretation of the theory of illumination that tries to get around some of these problems. This is the interpretation that Copleston and Gilson hold. It takes the analogy of the sun quite seriously. Augustine frequently puts his illumination talk in terms of sun metaphors, just as Plato did in the Republic. What are the implications of choosing this metaphor? Well, just as we see many things in the light of the sun even though the direct vision of the course of the light - that is, the sun itself - is reserved for the few (for the rest it just burns holes in their retinas), so too in illumination. We do not directly see the source of the light - God - but rather we see other things in the light of God. This view requires that illumination not put us in direct contact with divine truths, but rather simply regulates our minds so that it judges in accordance with the divine truths.

The details are tricky, but this will suffice for a brief sketch of the interpretation. Obviously, it nicely avoids problem (3) above, about the Beatific Vision. But it seems to me to be based on a selective choice of the evidence. Augustine does seem to say in some places that the divine truths themselves are put in direct contact with our minds, and they are the mind's objects, that it is not just that the mind sees other objects in the light of those truths.

It is true that Augustine does often speak of the regulative role of illumination. But it is not clear that this means anything else than that illumination in some cases involves propositions or judgments, and concerns rules.

I would like to call your attention to a really very good book on Augustine's theory of illumination: Ronald H. Nash, The Light of the Mind: St. Augustine's Theory of Knowledge. This slim volume helped me a lot.

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Last modified: Sun Dec 27, 1998 / Jeremiah Genest