In setting out the via negationis (or ‘negative’) approach to God, ‘De Theologia Mystica’ treatise of the 5th century mystic and theologian Pseudo-Dionysius the Areopagite describes the ineffability of God as “the Divine Dark”:

“The Divine Dark is nought else but that inaccessible light wherein the Lord is said to dwell. Although it is invisible because of its dazzling splendours and unsearchable because of the abundance of its supernatural brightness, nevertheless, whosoever deserves to see and know God rests therein; and, by the very fact that he neither sees nor knows, is truly in that which surpasses all truth and all knowledge.”

– The Pseudo-Dionysius: ‘De Mystica Theologia’

Referencing the Sufi poem ‘The Colloquy of the Birds’, Evelyn Underhill’s 1912 ‘Mysticism’ (’A study of the nature and development of man’s spiritual consciousness’) says that the sixth of the ‘Seven Valleys’ along the road to the hidden Palace of the King is known as the Valley of Amazement in which “the pilgrim’s receptive power appears to be taken from him and he is plunged in darkness and bewilderment. This is the state which Dionysius the Arcopagite, and after him many mediaeval mystics, called the Divine Dark, and described as the truest and closest of all our apprehensions of the Godhead. It is the Cloud of Unknowing: “dark from excessive bright.”

“’That meek darkness be thy mirror.’ What is this darkness? It is the ‘night of the intellect into which we are plunged when we attain to a state of consciousness which is above thought; enter on a plane of spiritual experience with which the intellect cannot deal. This is the ‘Divine Darkness’ – the Cloud of Unknowing, or of Ignorance, ‘dark with excess of light’ – preached by Dionysius the Areopagite, and eagerly accepted by his English interpreter. ‘When I say darkness, I mean a lacking of knowing . . . and for this reason it is not called a cloud of the air, but a cloud of unknowing that is betwixt thee and thy God.’ It is ‘a dark mist,’ he says again, ‘which seemeth to be between thee and the light thou aspirest to.’ This dimness and lostness of mind is a paradoxical proof of attainment. Reason is in the dark, because love has entered ‘the mysterious radiance of the Divine Dark, the inaccessible light wherein the Lord is said to dwell, and to which thought with all its struggles cannot attain.’

– Anonymous: ‘Cloud of Unknowing’

Reinhardt associates the phrase ‘the divine dark’ with Meister “Eckhardt” [sic] on several occasions, including the unpublished and undated texts ‘[Oneness]’ and ‘Black’ as well as in his ‘Black as Symbol and Concept’ contribution to the 1967 telephone seminar, subsequently published by artscanada. The phrase ‘the divine dark’ is more correctly associated with the Blessed Jan Van Ruysbroeck, as in:

When love has carried us above all things, into the Divine Dark, we receive in peace the Incomprehensible Light, enfolding us and penetrating us. What is this Light, if it be not a contemplation of the Infinite, and an intuition of Eternity?

– Blessed Jan Van Ruysbroeck: ‘The Spiritual Espousals’, c1340

It is possible that Reinhardt’s error in confusing Eckhart and Ruysbroeck was due to a book review published in ‘The Tablet’ in 1963, which said:

The mysticism of the New Testament with St. Paul’s “through a glass darkly” and the teaching of the mystical body takes us to Dionysius the Areopagite and the Confessions of St. Augustine with significant quotes from the famous Book X, the real basis and ground of European mystical thought. Two themes are traced of the divine dark or unknowing, and spiritual marriage. Dr. Happold has chosen his anthology with knowledge of the principal texts so that we have Eckhardt [sic] on time and Ruysbroeck on the mystic way.

– The Tablet: ‘Books of the Week’, p. 11, 06 July 1963