One afternoon, as photography professor Shane Booth was folding laundry, he heard a big crash. He left his room to find his front window smashed. When he returned to his laundry, it was tossed across the room.

These were not the only creepy goings-on in Booth's house. Vases moved around the house. Pictures fell to the floor. And every now and then he would catch the glimpse of a strange old man and hear strange laughter. Booth had no doubt: his house was haunted.

He is not alone. A recent poll conducted by a home security company found that 49% of American homeowners think their house is haunted.¹ The most common signs of haunting were odd voices and furniture moving on its own.

Since the Middle AgesThe Middle Ages was the period in European history that came between ancient and modern times. It lasted from about 500 to about 1500., ghosts have been seen as spirits of the dead, visiting Earth to settle their business. They are often depicted as pale, see-through versions of their living selves.

There is no scientific evidence that ghosts exist. Scientists have long called them nonsense. There are many explanations. Household mould causes us to feel a chill sensation. Poor light causes our brain to make mistakes in interpreting what we see. Slight brain damage can make us perceive objects moving.

Psychologists have explained ghost sightings as a sort of shield. When something bad happens, our mind searches for answers. If we cannot find any simple explanations, we might reach for stranger ones.

For those who think they have seen a ghost, however, there is no point trying to explain them away. Many respected figures have reported sightings, from Arthur Conan DoyleA 19th and 20th Century British writer, best known for the Sherlock Holmes series. to Winston ChurchillThe British prime minister during World War Two, and later from 1951 to 1955. ². Believers argue that we do not yet have the technology³ to properly perceive them. And they could be right.

Yes: We should keep an open mind. For all our science and technology, there is still so much we have yet to discover. The evidence today might be slim. But new findings can always emerge. 

No: Thousands of people claim to have witnessed ghostly activity. But no investigator has ever found the tiniest shred of evidence that they exist. Ghosts are simply a figment of our imagination. 

Or... Ghosts are not real in the way a person or an object is. But their popularity suggests that they do have a psychological presence, existing in the mind rather than the physical world.

Middle Ages - The Middle Ages was the period in European history that came between ancient and modern times. It lasted from about 500 to about 1500.

Arthur Conan Doyle - A 19th and 20th Century British writer, best known for the Sherlock Holmes series.

Winston Churchill - The British prime minister during World War Two, and later from 1951 to 1955.