Our only certitude regarding this author concerns who he was not. For long centuries he was believed to have been Denis or Dionysius the Areopagite, a convert of St. Paul, and the Corpus Areopagiticum received the attention and respect commensurate with that belief. The works were translated into Latin by John Scotus Erigena in the ninth century and were commented on by him and many other outstanding medievals, among them, Hugh of St. Victor, Albert the Great,Thomas Aquinas, and Denis the Carthusian. Internal evidence suggests that the works of Dionysius could not have been written much before the end of the fifth century. By placing his floruit in the year 500 we are being intentionally conservative.
The works of the Pseudo-Dionysius are the following: De coelestia hierarchia (On the Celestial Hierarchy), De ecciesiastica hierarchia (On the Ecclesiastical Hierarchy), De divinis nominibus (On the Divine Names), and De mystica theologica (On Mystical Theology). There are also ten letters.
Dionysius is a theologian; the whole burden of his works might be described as the exposition of what man can know of God and how, knowing him, he can name God. He is interested in proceeding, not according to the words of human wisdom, but in terms of Scripture. (Div. nom., 1) In search of knowledge of God in terms of what Scripture has said, however, he will also appeal to the efforts of philosophers. The most striking point about Dionysius is his insistence that the object of his concern is wholly beyond the ability of man to comprehend. The language Scripture uses to speak of God cannot express with any degree of adequacy what he is; a fortiori the attempts of men to speak of God must fail. His thought on this subject represents a division of theology which was to have a profound influence.
Dionysius says that to see and know God is to be accomplished through not seeing and not knowing him, for not to see God is truly to see him, not to know him is truly to know him, for we can adequately praise what is above all being by removing from him everything which pertains to existent things. In other words, our ignorance of God is something which must be achieved, for we will best know what he is not by attempting to work up to him through the grades of being. (Myst. theol., 2) First, there must be an affirmative theology (theologia kataphatika) in which we argue that God is a unique nature, that he is a Trinity of Persons. In the Divine Names Dionysius attempts to show what words can be applied to the divine nature, for example, Good, Light, Love, Being. Besides these names of intelligibles, we must discuss those words which are transferred from creatures to God in what may be called symbolic theology, that is, the many metaphorical names of God. Dionysius asks his reader to consider how names for God become more numerous as we move into metaphorical language. Negative theology (theologia apophatika) begins on the level of symbolic theology and ascends upwards, denying as it goes, until it becomes clear that God is ineffable, uncomprehended by our names taken singly or together.
While Dionysius' mystical works present the negative theology just described and the other works are all seemingly part of affirmative theology, these are not wholly distinguishable theological activities. The name of anything that is can be transferred to God as to its cause; this is simply a symbolic way of speaking. However, when God is named by means of "intelligibles," such as one, good, and so forth, he is indeed named from a created perfection, but there must be an accompanying denial understood: God is intelligent, and he is thereby named from what we know as intelligence, created and therefore limited intelligence, but the limitation must be denied of God. We end then with the assertion that God is superintelligent, that is, intelligent wholly above our ability to understand. That he escapes our ken is even more clear when we consider that he is superlife and supergood as well, and that in him these are but one perfection. The twofold theology thus implies a threefold procedure in naming God: affirmation, denial, and then the affirmation of a perfection which wholly exceeds our experience and ability to name.
The defect in our language and knowledge of God is explained with reference to us; on the side of God there is, of course, no defect. He is imperfectly named because he surpasses in perfection our ability to understand. The supreme Monad, he is the source of all the perfections we find scattered and distinct in creation; creation refers us back to him as the source of what we know only as limited and separate. The emanation of all things from God as their source and the return of all things to him as to their end is but one Neoplatonic note struck by Dionysius. His preference for the word One as the name of God, his utilization of the metaphor of light, with creatures as so many rays springing from a source too strong for our intellectual eye, the view that creatures are images -- all these reveal the influence of Plato, Plotinus, and Proclus. There is a processus or emanation of creatures from God (Div. nom., 5), and God, while one, indeed superunity, is thereby multiplied in his effects. We will find this extremely delicate concept in John Scotus Erigena as well, with the latter arguing that in this sense God can be called created. In phrases which will echo in Erigena, Dionysius speaks of God as "all in all" and of the divine Ideas as "predestinations." There is the distinct reminder of a stratified world, with the Ideas emanating from God as primordial caused causes and other things from them, as if existence-in-itself exists between God and the things that are. Moreover, the voluntariness of creation is somewhat diminished by Dionysius, and one detects a Neoplatonic suggestion that the levels of creation proceed from God in some necessary way.
Perhaps these few remarks will suffice to indicate the power as well as the obscurity of the thought of Dionysius. By far the most influential aspect of these writings is their doctrine on the unnameability of God, and thinkers of all persuasions will make an effort to adjust their thought to this claim. Those who find in Dionysius grounds for steering between the extremes of denying that we can know anything about God and claiming that God is a proportioned object of our mind would seem to be most faithful to him. That our knowledge of God is, compared to its object, no knowledge at all, in the sense that we cannot comprehend him, does not mean that creation provides no indirect way to meaningful language about its cause. In Cusa's phrase, our ignorance of God is a learned one, and Dionysius would hardly deny that we are better off after the efforts of affirmative and negative theology than we were before. It is a matter of some importance to note that not even Scripture, which is God's revelation to man, transcends the human mode of naming, which is to apply to God names of perfections best known to us in creatures.
For the works of Pseudo-Dionysius see Maurice de Gandillac, Oeuvres complètes du Pseudo-Denys l'Areopagite (Paris, 1943); J. Parker, The Works of Dionysius the Areopagite (London, 1897). See too A. B. Sharpe, Mysticism, Its True Nature and Value (London, 1910); E. C. Bolt, Dionysius the Areopagite: On the Divine Names and The Mystical Theology (New York, 1951); René Roques, L'univers Dionysien (Lille, 1954); and Denys Rutledge, Cosmic Theology (London, 1964).