The unknown writer of the Corpus Areopagiticum is one of the most important thinkers of the Eastern Church whose theology exercised an enormous influence on the so-called mystical tradition of the mediaeval West. His writings are characterised by a great theological depth and reveal a significant familiarity with neo-platonic philosophy, in particular with that of Proclus. Nevertheless, his dependence on Cappadocian thought and above all on Gregory of Nyssa is not to be neglected. One of the points of correspondence between the two thinkers is a remarkably frequent use of antithetic terminology, as another way of expressing deep meanings. The antithesis becomes the means by which the theological paradox is brought to light and revealed and signifies the tendency of the writer to pinpoint mystical experiences. It would thus appear self-evident that a study is needed of "Pseudo-Dionysius", use of this terminology, in the form of collecting the contradictory expressions and elucidating their meaning and importance for his thought.