And this proved to be more than just some weird, momentary emotional high that would pass in a day or two. After his December 6 vision, Thomas Aquinas left the Summa unfinished, and died only a few months later. One of the greatest intellects of his (or any) age willingly fell silent after that single, life-changing engagement with the ultimate mystery.

Almost exactly a century later, in May 1373 (we're not sure of the exact date), an ordinary but pious Englishwoman from the market town of Norwich fell ill with a fever so serious that her priest was called in to administer Last Rites. She lingered for a few days, hovering between life and death. Then one night, still believing that she lay on her deathbed, she received a series of sixteen vivid "shewings" (showings, or visions) of Christ, Mary, God, heaven, and even the devil. This dramatic event—or series of events—marked the turning point in her illness, and she recuperated.

Later, this anonymous woman took refuge as a solitary living in the Church of Saint Julian, and so today she is known only by the name of her Church—as Julian of Norwich. Not long after receiving her showings, Julian wrote a short book recounting what had happened to her; she revised this work to create a longer manuscript some twenty years after the event. In our time, more than six centuries after it was written, Julian's book—colorful descriptions of her visions, along with her thoughtful, prayerful reflections on their meaning—has achieved renown as a masterpiece of mystical devotion. Her vivid, earthy, and even radical explorations of Divine love—the love at the heart of Christ and the triune God, and what this love means for us—remain revolutionary in their message, even today. Not only that, but Julian's book will forever be significant as the first book written in the English language by a woman. Unlike Thomas Aquinas, who felt compelled to lay down his pen after his life-changing encounter with the mystery, Julian of Norwich felt called to pick up a pen—and to find her voice.

Lest you think mystical encounters happened only in the Middle Ages, let's take a look at a life-transforming epiphany (Divine manifestation) that occurred in the midst of the twentieth century to the best-selling monastic writer Thomas Merton. Merton's epiphany took place right in the heart of downtown Louisville, Kentucky.

On a late winter day in March 1958, the monk had come to the city for a business errand. (Members of his order typically do not leave the monastery unless there is a good reason to do so, like conducting business or going to the hospital.) As he came to a street corner in the middle of the bustling shopping district, Merton suddenly felt overwhelming love for all the people passing by, whom he described as "shining like the sun" in his vision. But this was more than some mere momentary fancy. Merton realized, in that flash of insight, that no matter how important it was for him to be a monk totally devoted to a life of prayer, meditation, and contemplation, he had an even higher calling as "a member of the human race."

Merton saw, at the center of every human being,a point or spark which belongs entirely to God, which is never at our disposal, from which God disposes of our lives. . . [it] is the pure glory of God in us. It is so to speak His name written in us . . . like a pure diamond, blazing with the invisible light of heaven. It is in everybody, and if we could see it we would see these billions of points of light coming together in the face and blaze of a sun that would make all the darkness and cruelty of life vanish completely.