On the Divine Names is about a kind of divine name which describes multiple attributes of godhead as a whole. Tho the names refer to it as a unity, each name is different & so, taken together, they differentiate it. The implicit distinction between the godhead's unity & the multiplicity of the names is reflected in the names' structures themselves. Each includes a Greek prefix: hyper-, which indicates the unity of the godhead to whom names are applied. But each name is different, indicating the self-multiplication of the godhead. The result is a set of names like “over-good,” “over-being” & “over-life.” Dionysius also makes use of a 2nd, equivalent prefix: pro-. God is “pre-good” & “pre-being,” meaning it has the attributes of creatures in a way that transcends both creature & attribute. The prefixes must be applied strictly to the names when they're used of God itself. On the other hand, when the names are used only of God as cause, the prefixes may be left off, since the causality of God is already a procession into the differentiation properly signified by each of the different names. The most proper object of the names is the highest creature. The exemplary instances of goodness, being & life are the highest of the angels or intelligible minds. For this reason, he frequently refers to this type as an “intelligible name.” He incorporates into the number of intelligible names the traditional Neoplatonic intelligible categories: being, identity, difference, rest & motion, as well as the being, life & intellect triad. The fact God transcends the proper meaning of these names doesn't mean it ought be called “non-being,” “non-life” or “non-intellect.” He prefers to say God is “over being,” “over life” & “over intellect.” Few can contemplate the intelligible names in their purity. We require the names to be incarnated in visible things. Unable to see being, life & wisdom in themselves, we need a visible being who is living & wise. Such a person can then become the means by which we contemplate the intelligible. The teacher Hierotheus is one such visible incarnation of the names. But Hierotheus may do more than incarnate the names. He can also unfold them in speech, taking the unitary name of “being” & describing it at length, as is done in chapter 5. As he describes it, the name unfolds itself into a form that is more multiple, because of the many words used in his description. It thus approaches the multiple character of the human way of knowing & becomes more easily understood.
When Dionysius praises “dissimilar similarities” over seemingly more appropriate symbolic names for God, he explains that negations are true to God & such dissimilar names serve as such negations. The Mystical Theology has this last, most arcane form of theology as its subject. Negations are properly applied not only to the names of the symbolic theology. Any & all of the divine names must be negated, beginning with those of the symbolic theology, continuing with the intelligible names & concluding with the theological representations. The godhead is no more “spirit,” “sonship” & “fatherhood” than it's “intellect” or “asleep.” These negations must be distinguished from privations. A privation is simply the absence of a given predicate, which could just as easily be present. The absence of the predicate is opposed to its presence: “lifeless” is opposed to “living.” But when we say that the godhead isn't “living” we don't mean it's “lifeless.” The godhead is beyond lifeless as well as beyond living. For this reason, he says our affirmations of the godhead aren't opposed to our negations, but that both must be transcended: even the negations must be negated. The most arcane passages of Mystical Theology revolve around the mystical as taken in itself & not as the act of negating the other forms of theology. Dionysius says that after all speaking, reading & comprehending of the names ceases, there follows a divine silence, darkness & unknowing. All three of these characteristics seem privative, as tho they were simply being the absence of speech, sight & knowledge respectively. But Dionysius doesn't treat them as privative. Instead, he uses spatio-temporal language to mark off a special place & time for them. Using as example Moses' ascent up Mt Sinai, Dionysius says that after Moses ascends thru the sensible & intelligible contemplation of God, he then enters the darkness above the mountain's peak. The darkness is located above the mountain. Moses enters it after his contemplation of God in the various forms of theology. Dionysius leaves the relation between Moses & the darkness obscure. Some commentators reduce it to a form of knowing, albeit an extraordinary form of knowing. Others reduce it to a form of affective experience, in which Moses feels something he can never know or explain in words. Dionysius himself does not give decisive evidence in favor of either interpretation. He speaks only of Moses' “union” with the ineffable, invisible, unknowable godhead.--Stanford Encyclopedia (edited)