T. M. Luhrmann in Harper’s:
Hearing voices is, it turns out, surprisingly common. In 1894, a team led by Henry Sidgwick, a philosopher at the University of Cambridge, published the Census of Hallucinations, which surveyed 17,000 people in the United Kingdom and found that around 10 percent of them reported having seen, heard, or felt something “which impression, so far as you can discover, was not due to any external physical cause.” Many more recent studies have supported that observation. In 1983, two psychologists, Thomas Posey and Mary Losch, modified Sidgwick’s basic question and found that the rate skyrocketed to 70 percent when participants were given the opportunity to say that they had heard a voice but decided that it wasn’t real. And as many as 80 percent of people who have lost a loved one report hearing, seeing, or feeling them in the months after their death.
For years, I have spoken with such people. I study the odd and the uncanny—voices, visions, the supernatural. I seek out people who have experienced otherworldly events, and as I have published my research they have sought me out in turn. People have told me that while they were driving, God spoke up from the back seat and said that he would always love them, or that as they stood looking at the ocean, the waves became light and language. Others have shrugged and said that they were speeding and God’s voice came over the radio to tell them to slow down.