Henri Nouwen writes:
"Spiritual formation requires taking an inward journey to the heart. Although this journey takes place in community and leads to service, the first task in to look within, reflect on our daily life, and seek God and God’s activity right there. People who dare to look inward are faced with a new and often dramatic challenge: they must come to terms with the inner mysterium tremendum—the overwhelming nature of the inner life." (Nouwen, Henri, Spiritual Formation: Following the Movements of the Spirit, K 195)
I first encountered this term in Rudolf Otto's classic The Idea of the Holy. "Mysterium tremendum" (MT) refers to an experience of awe, even fearfulness, in the encounter with God.
MT is, for Otto, a non-rational (= non-discursive) experience. "Non-rational" does not mean "irrational," but rather an experience that cannot be captured in the steel nets of logical language. It cannot be discoursed about; hence it is a non-discursive experience. Put more simply, there's way more in the experience than can be captured by our intellectual reason. Surely the real encounter with the Living God has this quality.
Otto also coins the term "Numinous" to refer to the non-discursive experience of God. "Numen," for Otto, refers to God. A "numinous" experience is a way of speaking of a God-encounter that cannot be fully captured by human reason. Such experience is what Paul Ricoeur and others call a "limit-experience," which contains a "surplus of meaning." (On Ricoeur and limit-experiences see, e.g., here, p. 66)
Picking up on Otto's language, C.S. Lewis writes:
"Suppose you were told that there was a tiger in the next room: you would know that you were in danger and would probably feel fear. But if you were told "There is a ghost in the next room," and believed it, you would feel, indeed, what is often called fear, but of a different kind. It would not be based on the knowledge of danger, for no one is primarily afraid of what a ghost may do to him, but of the mere fact that it is a ghost. It is "uncanny" rather than dangerous, and the special kind of fear it excites may be called Dread. With the Uncanny one has reached the fringes of the Numinous. Now suppose that you were told simply "There is a might spirit in the room" and believed it. Your feelings would then be even less like the mere fear of danger: but the disturbance would be profound. You would feel wonder and a certain shrinking–described as awe, and the object which excites it is the Numinous. " (C.S. Lewis, The Problem of Pain)
Nouwen uses "mysterium tremendum" metaphorically to refer to the encounter with the depths of one's own being, "the overwhelming nature of the inner life," and God and God's activity happening there. Referring to another book I read a long time ago, this is what Morton Kelsey called the "adventure inward." Call this the Journey to the Center of the Self. Entrance into the inner sanctuary, the temple within ("You are a temple of the Holy Spirit").
Here is where spiritual formation takes place. "Spiritual formation requires taking an inward journey to the heart." (Nouwen) The inward journey is dangerous and exhilarating, as much so as interstellar space travel would be. This is how those who have made the journey and lived to write about it describe it.
Dare to travel inward. Adventure deep, led by God's Spirit.
- Look within.
- Seek God and God's activity there.