‘The feeling of it may at times come sweeping like a gentle tide, pervading the mind with a tranquil mood of deepest worship... It may burst in sudden eruption up from the depths of the soul with spasms and convulsions, or lead to the strangest excitements, to intoxicated frenzy, to transport, and to ecstasy. It has its wild and demonic forms and can sink to an almost grisly horror and shuddering… It may become the hushed, trembling, and speechless humility of the creature in the presence of – whom or what? In the presence of that which is a Mystery inexpressible and above all creatures.’
The Idea of the Holy: An Inquiry into the Non-Rational Factor in the Idea of the Divine and its Relation to the Rational (1917)
Rudolf Otto
In Summary

A famous thinker argues that the heart of religion is the experience of God as Other: as so far beyond our concepts and comfort zones that it elicits awe and trembling.


Spiritual explanations have often been reduced to naturalistic ones, allowing the other academic disciplines to usurp the throne of religion. Instead of God creating humans in God’s own image, biology argued that we evolved from the same ancestors as apes. Instead of the Bible revealing the moral law through the Ten Commandments, ethics became the domain of moral philosophy. Instead of historical events being guided by God, alternative explanations soon arose from sociology, economics, and political science. To some, the realm of the religious seemed like it was ever-shrinking, surrendering more and more territory to the other disciplines with no ceasefire in sight.

Enter Rudolf Otto, a German philosopher and theologian at the turn of the twentieth century. Otto set out to find the irreducible: the aspect of the mystical that could not be reduced to any other discipline but was the unique property and domain of religious studies. His journey led him to Morocco, Palestine, India, China, Japan, and the United States, as he attempted to distil a universal essence of faith that was reasonably consistent throughout the world’s religions. The Idea of the Holy (1917) is the now-famous account of what he found.


While Otto believes religion is mostly rational, he also admits that there is some aspect of it which goes beyond reason, suggesting that it cannot be reduced to rational philosophy alone. In turn, while religion and morality have often gone hand-in-hand, ethics is not broad enough to deal with the tremendous awe and humility of experiencing an infinite God. And since reason and ethics exemplify what we as humans find comforting – i.e., how we think and what we define as right and wrong – they primarily tell us about ourselves, not about the God who is beyond us. If one wants to find the true and irreducible heart of religion, one must instead shroud themselves in the foreign and exotic otherness of the ‘Mysterium Tremendum.’ 

The Tremendum refers to the supernatural dread and overpowering sense of awe one feels when standing in the tremendous presence of the Holy. The Mysterium signifies the ‘wholly Other’ nature of this being, such that none of our prior experiences, ethical expectations, or empirical frameworks can grasp its mystery. We are left utterly out of control and gripped with the wondrous horror of the unknown. One sees examples of this in the Old Testament God of wrath, as well as in the pagan worship of frightful demons and eerie spirits. 

Yet this is not merely the emotion of fear – which would fall under the purview of psychology – but something else altogether. We are afraid of what a lion might do to us, yet our fear of a ghost is not merely of what it might do but of what it is. The very nature of the supernatural sparks a human response that is distinct from our pragmatic fear of natural dangers. As such, it requires a new category and definition of religious ‘dread’. For example, even if we know that God is on our side and will not hurt us, we may still shudder in his infinite presence. This impractical dread is the sort of experience that one either has had or not, and, if not, then nothing anyone else says can sufficiently convey it. While ethics, philosophy, and psychology attempt to make logical sense of things for us, the ‘otherness’ of this encounter leaves room for the Holy (or what otto calls the 'Numinous') to emerge.

Just when one begins to wonder if Otto is going to leave us in terror, he fills in the rest of the picture. There is a ‘dual’ nature to the Holy, such that it simultaneously frightens and entices us. We are fascinated and drawn to the Holy mystery, desiring to become one with it. Precisely because this is so far beyond our understanding, it can be paradoxically both chilling and comforting, wrathful and loving, rational and irrational.


The Idea of the Holy is one of the defining works of 20th-century religion, drawing upon a variety of Eastern and Western thinkers in order to carve out an irreducible space that is uniquely the property of faith. Otto posits that there is an immediate, practical, lived experience of the Holy that breaks into our lives. While we can neither explain nor explain away this experience, we can nonetheless still have it, coming face to face with that which is wholly Other. Standing before the Mysterium Tremendum, we can be both terrified and safe, humbled and elevated, mystified and lucid, judged and forgiven. Our inability to rationalise this experience is precisely what gives it the flavour of truth, suggesting that it is more than merely a projection of our human desires and thoughts. As C.S. Lewis – who was heavily influenced by Otto – wrote: ‘God is not a tame lion.’

Further Reading By This Author

Otto’s output also included the books Naturalism and Religion, Religious Essays, Christianity and the Indian Religions of Grace, Life and Ministry of Jesus, Mysticism East and West, The Original Gita, and The Kingdom of God and the Son of Man. 

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