For many thousands of years humans have felt the need to communicate with a power greater than themselves. When life seemed tough in those ancient days, it was comforting to believe that what man couldn't deal with could be passed "upwards" for that greater power to help with. To us nowadays this may seem like an abdication of responsibility, but to ancient man with his limited control of natural events, it must have felt good to have a superior being on your side.

That belief in a super-natural power went hand in hand with the belief that when a person died, somehow part of him (the essence or "spirit" of the person) continued to exist after death as a separate entity independent of his physical body, and that spirit moved on to new pastures to live another kind of life. They didn't know exactly where the spirit went to, but it must have gone somewhere because it was not visible on earth.

Ancient man was in awe of natural forces - wind, rain, lightning, thunder, storms etc., believing these were expressions of the mood of the great creator who (logically) lived high in the skies. It made sense that when a person died, his spirit went to the skies too. It was also assumed (wrongly, as we now know) that when the spirit was set free from the body and went to join the creator in the skies, that spirit was suddenly all-knowing and powerful, and was immediately endowed with great wisdom and insight. Thus it became acceptable to ask one's departed friends and family to use their new-found wisdom to help those left behind on earth with advice and problem-solving.

Quite how ancient man discovered the means to communicate with departed spirits is not known (perhaps trial-and-error?) but we do know that methods were discovered and honed over thousands of years, using nothing more than the human mind and a few mental props such as incense and oils, musical instruments and drugs, to produce an altered state of consciousness where physical reality was suspended for a while in order to facilitate communication with the spirits.

Several methods were devised, which differed according to the culture of the particular area. One method, used by the Ancient Greeks, was to spend a few days in dimly-lit underground caves, and when the time was considered right the person seeking answers to life's problems would stare into the surface of a large oil-filled cauldron and receive the required answers. Another method consisted of staring into a crystal ball - after a while images were conjured up in the mind. More modern methods involve blindfolds, earplugs and water flotation tanks. The common theme running through all methods is sensory deprivation.

Put simply, when the mind is deprived of external stimulation such as sensory information from the eyes and ears, it will tend to form its own sights and sounds. Nature abhors a vacuum!  And if the mind can be influenced to think of a certain pre-determined subject when all other sensory input is withdrawn (or just as importantly, when the sensory input bores the mind), then it will often produce images relating to that subject. This seems to be the way in which the manteum works - convince the mind beforehand of the subject matter and it will often produce the desired result, namely communication with those departed souls.