For Immanuel Kant (1724-1804), “one can never be sure that the Academy of Sciences will choose such a subject, for the contest; not that each member be convinced of the futility and lies of all these narratives, but because the law of prudence puts wise bounds to the consideration of these issues. The ghost stories always encounter secret believers and will stil be thel object, in public, of a fashionable disbelief.”
The second part of the nineteenth century until the mid-twentieth, and even until today, many scientists and parapsychologists have investigated these phenomena. Among these are: astronomer Camille Flammarion (1842-1925), Charles Richet (1850-1935) Nobel Prize in Medicine, writer Frank Podmore (1856-1910), parapsychologist Ernest Bozzano (1862-1943), french professor Jean Prieur ( 1914-), doctor of letters Claude Lecouteux (1943-), physicist and psychologist Walter von Lucadou (1945-), etc. They are often grouped in institutes such as the Society for Psychical Research, founded in 1882 in England, or the Metapsychic International Institute, established in 1919 in France.
Currently, the scientific community generally considers that, deceptions and misunderstandings aside, most manifestations of ghosts presented as genuine have no physical reality. The spectral apparitions do not fall within the scope of zetetic movement studies, this one being limited to refutable hypotheses and excluding, in fact, everything related to beliefs. For Pascale Catala, “only a rational approach based on various scientific disciplines (physics, psychology, psychiatric, sociology, neurophysiological, etc. will separate the true from the false.”
(The Absinthe Drinker -Painting by Viktor Oliva (1901))
Hallucinations are defined as perceptions in the absence of external stimuli. They should be distinguished from illusions, which result from altered perceptions of existing external stimuli, and hallucinoses, which are perceptions in the absence of external stimuli but with preservation of consciousness of the endogenous kind (which has an internal cause) of perception.
An important characteristic of the psychotic state is the lack of sufficient awareness of taking the pathological nature of symptoms (Anosognosia). The patients think their behavior, and the hallucinatory experiences they live, are in no way unusual or strange.
(The Nightmare (1781) by Heinrich Füssli)
A relatively common sleep disorder, known under the name of sleep paralysis, can probably explain many cases of obsession, when these occur when the witness is lying in a bed.
The subject, about to fall asleep or awake, but completely conscious, is unable to perform any voluntary movement. To this unpleasant feeling, are commonly associated auditory hallucinations such as footsteps, voices and various sounds and impressions of oppression, suffocation and presence of an evil person in the room. Visual hallucinations are quite infrequent.
Much less common are other expressions, as sensations of vibration, pain or cold, smells, movements of blankets, etc. These hallucinations are experienced as real events, accompanied by a feeling of extreme or even fatal danger. More rarely, it can be felt anger, sadness, a feeling of ecstasy or erotic desires.
A patient of twenty-two years without a psychiatric history, treated at the Federal Polytechnic School of Lausanne (Switzerland) for a problem of epilepsy, had the unpleasant sensation that a person placed behind her is trying to hug her, when the researchers stimulated the electrodes in his brain to the temporoparietal junction. A malfunction of this brain area is already suspected of being behind the astral sensation.
Aches and infrasounds
Scientific research allowed to question infrasound – sounds at frequencies below 20 hertz (Hz), inaudible to the human ear – in producing feelings of anxiety, fear or sadness, and even hallucinations. The physiological and psychological effects of infrasound were discovered in the early twentieth century. Nazi propaganda would have used to enhance the excitement of the crowds during Adolf Hitler’s speech and would later sought to build sonic weapons that seem to have remained experimental. End of 1963, Dr. Vladimir Gavreau, a researcher in electro-acoustic laboratory of Marseille, was confronted with violent discomfort, repeated headaches and nausea of its employees. After extensive research in all directions, he discovered that their cause was a fan which emitted inaudible sounds with a frequency of 7 Hz.
During an experiment conducted by Dr Richard Lord, acoustics researcher at the National Physical Laboratory, and Professor Richard Wiseman, a psychologist at the University of Hertfordshire, very low frequency sounds were emitted in four pieces played during a concert bringing together 750 people in London. At the exit, 22% of viewers said they had reactions of fear or sadness over the passages in question. According to Professor Wiseman: “Some researchers have suggested that this level of sound can be found in some homes say haunted and cause strange sensations commonly attributed to the presence of a ghost – our findings support this hypothesis.” The wind rushing through the long corridors and chimneys castles might be the cause of these infrasound. According to Vic Tandy, an engineer at the University of Coventry, sounds with a frequency of approximately 19 Hz can resonate the human eyeball, causing blurred vision and hallucinations.
Earth naturally immersed in a magnetic field of its own, with the vertical component on its surface being stable at around 500 mG. In the 1980s, studying the behavior of dowsers, Professor Yves Rocard said that a human being could be sensitive to a change in magnetism of the order of mG. However, in certain places supposed haunted, it was measured considerably more magnetic fields, up to 825 mG. Some people might be particularly sensitive, and interpret their feelings based on their personal beliefs.