There is a way downwards and a way upwards – we have this already in Heraclitus who says that in everything there is a trend from earth over water over fire to air, and an opposite trend from the air to earth, i.e., every living being is a tense reality, in which there is a fundamental tension, a tension of the creative power of being going down, and the saving power of being going up. The three stages of the way upward are purgation, or purification (this is the ethical-ascetic realm); illumination (this is the realm of mystical understanding); and union or perfection (this is the return into the unity with God. In this last stage something takes place which became the foundation of the modern world through Nicholas Cusanos, namely what Dionysius calls the mystical ignorance; what Cusanos called the learned ignorance (docta ignorantia). Of this the two men say that it is the only ultimate true knowledge. And again this word “ignorance” says we don’t know anything special any more when we have penetrated into the Ground of everything that is. And since everything special is changing, it is not ultimate reality and truth.