One afternoon, as photography professor Shane Booth was folding laundry, he heard an almighty crash. He left his room to find his front window had shattered, with no sign of a perpetrator. When he returned to his laundry, it was scattered across the room.

These were not the only strange 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 spectralGhostly. old man and hear strange laughter. Booth had no doubt: his house was haunted by ghosts.

He is far from alone. A recent poll conducted by a home security company found that 49% of American homeowners believe their house is haunted, rising to 57% in urban areas.¹ The most common signs of haunting were disembodiedBodiless. voices and furniture moving on its own.

The belief in ghosts is nothing new.² The MesopotamiansPeople who lived in a historical region of Western Asia, between the Tigris and Euphrates rivers. thought that we become ghosts at the moment of death. Ancient Greek poet HomerAncient Greek poet, author of the Illiad and the Odyssey. It is unknown if Homer is a single author or a name for a composite oral tradition. describes ghosts "as a vapour, gibbering and whining into the earth". Roman essayist PlutarchA Greek philosopher and priest known for his biographies of Greek and Roman figures. wrote about a ghost haunting a bath house.

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 unfinished business. For centuries, they have been depicted as pale, near-transparent, incorporealWith no physical matter or existence. versions of their living form.

Yet despite their long cultural history, there is no evidence that ghosts exist. Scientists have long considered them nonsense. As early as 1813, physician John Ferriar blamed them on optical illusions.

Since then, there have been many scientific 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 protective shield. When something unexpected and unpleasant happens, our mind scrambles for answers. If we cannot find any rationalLogical or reasonable. ones, we might reach for paranormalBeyond normal scientific understanding. explanations. 

This could explain why there has been a surge in ghost sightings since Covid-19. Folklorist Tok Thompson says: "Many times people lost loved ones with no last contact, no funeral". The virus caused many sudden deaths. The minds of the bereaved dealt with the shock by imagining their loved ones still be present.

Lockdowns also gave us more time to notice the noises and movements that a house makes as it changes temperature throughout the day.

For those who believe in ghosts, however, there is no point trying to explain them away. Many eminent 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. ⁴.

Some believers can argue that we do not yet have the technology to properly perceive ghosts. Others think that we should clarify what ghosts are. Our perception is shaped by our consciousness. Journalist George Monbiot writes: "We inhabit parallel worlds of perception, bounded by our interests and experience". Ghosts might be projections of our thoughts and feelings - in short, part of us.

Yes: We should keep an open mind. For all our advances in 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 paranormal 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 persistence in culture suggests that they do have a psychological presence, existing in the mind rather than the physical world.