My two cents are that apparitions are one class, and far from the most most remarkable, of those happenings called religious experiences. These happen to people and seem to be part of who we are. I think it would be more correct to call these spiritual experiences, for they do not always take on the flavor of orthodox religious icons, symbols, and characters. Sometimes they involve ideas or understandings. What publically to make of them is problematic, but they can have life-changing meaning and power to the individual who has the experience.