Writing about religion in the digital age means that your readers respond. They have, of course, always responded; but in an age of stamps and paper, it required some effort. Now, it requires almost none. I still have the slender file of the paper letters people sent me after my first book came out in 1989. In 2012 I posted a short piece on CNN’s Belief Blog: “If you hear God speak audibly, you (usually) aren’t crazy.” There were more than 7000 comments. I couldn’t even read them.

Mind you, I didn’t want to. Readers can be unkind—perhaps because the swiftness of the digital writing process means that readers can blurt out the first vehement thoughts they might have edited away if they had to go to their typewriter and type out text on paper, or because the anonymity of posting means that the normal constraints on meanness disappear, or because people think they’re having a conversation just with other posters, and don’t really think of the writer as a fellow creature at all. Whatever the reason, people say horrible things in online posted comments. One gem from my Belief Blog essay: “This lady is (usually) crazy.”

Even when someone writes directly in an email, and so presumably has some sense that you, the writer, breathe air and share their earth, they are often not kind. “So here you are, highly educated, yet you sound in your articles and website as if you are a shil [sic] for religion…Academic degrees are no evidence of intelligence.” And their comments are sometimes odd. “It is impossible to engage in pure, unfiltered communication with other humans. I include my spouse of 47 years because our DNAs are so different.”

Readers can also make you weep. Spirituality is often intensely private. To find words for someone’s experience of God can feel like reaching out with your hands to cup the mist. When readers tell you that what you wrote moved them, they can make you feel that when you write, you do something, and that it matters. “I want to let you know that my copy of your book is as marked up and underlined as an evangelical Bible.”

When readers respond they teach you things. Sometimes they tell you what you have seen is true, and then they give you more and sometimes better examples. That’s particularly useful for a student of spiritual experiences, some of which are as rare as eagles.

Ms. Luhrmann,

I read your article on CNN and enjoyed it.

I once had God talk to me. It was the most amazing thing I have ever heard. It saved my life. My company was on the way to bankruptcy. I was under tremendous pressure. I was home on a Sunday evening and I heard this annoying voice saying “Go to church!” I was never very religious. [The voice] was really grating and repeating. I went to church early and sat in the pew. I started praying about business and what to do when I heard this voice inside my head call me. I looked to the crucifix on the altar and felt this amazing feeling of warmth, contentment and support, all rolled into one. The voice continued and told me that I was loved and I would be okay. I knew it was God. I burst into tears … I was able to save the business.

You can interview a hundred people, and few of them will have a sensory experience of God this strong and clear and consequential. But when thousands and thousands of people read an account you have written about people who have heard God speak audibly, some of them will feel themselves recognized, and they will sometimes then write to tell you their own story.

That’s how I discovered tulpas. Someone on the other side of the planet read one of my short pieces about unusual sensory experience and wrote to me to tell me that he had created a thought-form that spoke to him. He explained that he had simply invented an imaginary companion, and he had focused on her intensely until she became independent of him and began to speak and act on her own. It turns out that there are thousands of people like him (see the subreddit), inspired by a few stray paragraphs in Alexandra David-Neels’ remarkable memoir of her voyage in Tibet. In Magic and Mystery in Tibet (1932 in the English translation) she not only described what tulpas were but how she generated her own: a short, fat, jolly monk who showed up, hung around, and became real enough to her that she reported that she saw him and felt him pat her on her shoulder.

So writing about religion in the digital age has become for me an unanticipated means of doing research. I began talking to people who made their own tulpas, and some of them began to read me. “When God Talks Back…is the most important tulpa-related thing I’ve ever read,” one wrote. “If I did a full text replacement of the word “God” with the word “tulpas” about 80% of this book would still be applicable to us.” Thence ensued a conversation about the nature of God. “If you try very, very hard, you can convince yourself that you’re having telepathic conversations with Johnny Depp,” one skeptic wrote. “The fact that you’re not actually having telepathic conversations with Johnny Depp doesn’t mean that Johnny Depp doesn’t exist. It just means you’re not actually having telepathic conversations with Johnny Depp.” A Pentecostal tulpa-creator said: “I’ve never been good at hearing God’s voice, and I’ll be honest, that ability being hindered was one of my concerns when making a tulpa. But talking to God and talking to my tulpa are different. I don’t have full blown conversations with God like I do with Rose.” I began to wonder how people discriminated between different types of mental agents. My questions around this point became more pointed and more precise.

Not all the stories are about the quirky tide pools of human experience that the Internet makes more visible. One woman wrote to me to ask whether religion could make someone mentally ill, or make a mental illness worse. She explained that her son had begun hearing voices. She thought he might be developing schizophrenia. But her sister, who attended a branch of the church I’d written about, told him that he was hearing demons. He was spiritually sensitive, not crazy. For two years her sister taught him about his demons. Together, they did banishing rituals and exorcisms and she taught him more about the Bible. He was impressed by her wisdom, because what she said made such good sense of his experience. To the mother’s eye, her son’s symptoms were getting worse, but he refused to seek treatment because, as he insisted, he was not ill. Then he developed a relationship with an archangel, and decided that his grandmother—his mother’s mother, who lived with them—was demon-possessed. One morning the archangel announced to him that the witch must die. The woman’s son walked upstairs and stabbed his grandmother with a kitchen knife while she was eating breakfast. She bled to death on the floor.

That conversation, which began over email but progressed to a phone call, was not the only conversation with readers in which I have slipped down to sit on the floor, gripping the phone, throat tight with distress. “I have this habit,” a young woman explained to me over the phone in a conversation about demons: “I buy guns.” She talked about hearing demons, and about being told she wrote like Søren Kierkegaard. “You could look at it as a compliment but it wasn’t.” She didn’t think there was much truth to religion but she thought of her voices as religious, because to think of them as mystery and radical otherness was the only way in which they made sense. “Voices are so real to me. So compelling. I know I hear them and they are outside of me. God I have no such surety of. And yet there is more warrant for God, no matter how abstract, than there is for the voices I hear. It’s actually kind of crazy-making when I try to make sense of it. I doubt God—profoundly so. I don’t doubt the voices when they talk. Anyway, I keep thinking about your book as I try to figure it all out.”

In the digital age people reach out to talk to me sometimes because they want affirmation that they are not unique, sometimes because they want to sell their story, sometimes because they want the attention. But often, I think, they reach out because they do not know what to do with these intense feelings. Telling the story lessens the pain, perhaps by casting the unthinkable into words. “I think perhaps telling our whole story to you, with a recorder going, may have helped me move to the next stage of thinking about all this. When I came downstairs [after the murder] as the police and ER rushed into the house, I collapsed on my bed with my head covered protectively by my hands, and froze there; and to some extent I’ve felt ever since that there’s a ghost of myself still sitting there, and only part of me is functioning. That sense is gone. [After telling my story] I feel like my ghost got up and rejoined the rest of me.”

To write about religion—and particularly, to write about spiritual experience—is to write about emotionally vivid events. Doing so in the digital age vastly expands the number of events the writer encounters. By their nature, these events are rare. They are private. They are unusual. The Internet makes it possible for a reader who has experienced such an event to open up to the writer the way someone talks intimately to an empathic stranger on a bus. That reader might be shy before a neighbor, but he or she will tell you. And so the writer can learn a great deal.

As long as she can tolerate human pain, and can grit her teeth and ignore the insults.