Western Europeans during the Early Middle Ages were inclined to believe the most outlandish ideas, particularly where religious matters were concerned. For instance, they believed Satan was everywhere; thus one monk wrote that "the whole air is but a thick mass of devils." Another chronicler told of how a wicked priest tried to take sexual advantage of a woman. He kissed her with a Communion wafer in his mouth, hoping this would win her by affection; instead, the wafer caused him to suddenly grow so tall he could not leave the church building. He buried the wafer in a corner of the church, then later dug it up— only to find that it had turned into a bloodstained figure of Jesus on the cross. People who heard this story most likely gave it the same solemn respect that a modern person would for a nightly news report.
Superstition was an everyday part of life. Immediately after a death in the house, for instance, all bowls of water would have to be covered so that the loved one's spirit would not drown. Care also had to be taken to ensure that a cat or dog did not walk across the corpse in the coffin, lest the dear departed turn into a vampire. Some superstitions have survived from medieval times—for instance, saying "bless you" when someone sneezes, since sneezing was viewed as an opportunity for a demon to enter the body.
In place of scientific knowledge, people often relied on highly uneducated ideas about cause-and-effect relations. For example, people readily accepted an idea that has since come to be known as "spontaneous generation." If one were to leave food out in a room for long enough, it would of course draw rats; but medieval people, seeing a rat where a piece of cheese had been, reasoned that the cheese had actually turned into the rat. They also believed in what was later dubbed "acquired characteristics," another simple-minded fallacy. According to this notion, if a man lost his right arm in an accident, his children would be born missing their right arms as well.