Around 1848 in the United States, attention was called to a number of strange phenomena consisting of noises, raps and movements of objects without any known cause behind them. These phenomena frequently occurred spontaneously with remarkable intensity and persistence, but it was noted that they occurred more particularly under the influence of certain persons called mediums, who could, in a manner of speaking, induce them at will, allowing the phenomena to be repeated. Tables, especially, were used for this, not because they were favored more highly than some other object, but solely because they were the most convenient article of furniture, and could most easily and naturally be sat around. To being with, the table would start spinning, but then it would move about, jerk, topple over, rise up into the air, and make forceful rapping noises, etc. This was the phenomenon that gave rise to the name turning tables or the dance of the tables.
At first the phenomenon might have been fully explained as resulting from some electric or magnetic current, or possibly the action of some unknown fluid, and such was the opinion regarding it. But it did not take long before it was realized that the various expressions of the phenomenon displayed signs of intelligence; hence the movement of the table was obeying a will, and would move to the right or to the left toward a designated person. At that person’s command, it would stand on one or two legs, would strike the floor the number of times requested, would beat to a rhythm, etc. Consequently it became obvious that the cause was not purely physical, and according to the maxim: if every effect has a cause, every intelligent effect must have an intelligent cause, it was concluded that the cause of this particular phenomenon must be an intelligence.
What was the nature of this intelligence? That was the question. At first, it was thought that it might be a reflection of the medium’s or the onlookers’ intelligence, but experience soon showed that idea to be impossible, because matters completely outside the thought and knowledge of those present were obtained, and which were even contrary to their ideas, will and desire; thus the manifesting intelligence could only belong to some invisible being. The way to tell for certain was quite simple: start a conversation with it. This was done by means of an agreed-on number of strikes to designate a yes or no answer, or to designate letters of the alphabet, the latter rendering answers to the most diverse questions asked of it. This phenomenon was first given the name talking tables. When asked about their nature, all of the beings that communicated in this way stated that they were spirits and that they belonged to the invisible world. Since the same effects were produced in many different localities by the agency of different mediums, and also because they were witnessed by very honest and well-educated persons, there was no way they were a game of illusion.
The phenomenon spread from the U.S. to France and the rest of Europe, where, for a few years, the turning and talking tables were a fad and were a form of entertainment in salons. After their novelty wore off, they were set aside to make way for a new distraction.
The phenomenon did not take long to appear in a new form, which removed it from the realm of simple curiosity. The scope of this brief summary will not allow us to follow it in all its phases, so we shall proceed with no further ado to what was to be its most characteristic phase, the one that most specially gained the attention of serious persons.
First of all, we must state, in passing, that the reality of the phenomenon encountered with many opponents; some, without taking into account the disinterestedness and honorability of the experimenters, saw it as nothing more than a fraud, a skillful game of sleight-of-hand. Those who did not believe in anything outside the world of matter, who did not believe in anything but the visible world, and who thought that everything died when the body did – materialists, in other words – those who regarded themselves as being of sound mind, rejected the existence of invisible spirits as being in the class of absurd fairytales. They labeled as crazy those who took the matter seriously and heaped sarcasm and mockery on them. Others, unable to deny the facts, and influenced by a certain order of ideas, attributed the many forms of the phenomenon to being exclusively the work of the Devil, thus seeking to scare the timid. But nowadays the fear of the Devil has singularly fallen out of favor; he had been spoken of so much and portrayed in so many different ways that people had gotten used to the idea, and hence many said that they would like to have the opportunity to see what he really was like, after all. The result was that, except for a small number of timid women, the news that the actual Devil himself had appeared on the scene was regarded as somewhat sensational to those who had never seen him, except in painting and the theater. This was a powerful stimulus for many persons; therefore those who wanted to use such means to erect a barrier against new ideas defeated their own purpose, and without meaning to, they became more and more effective advertisers the more they ranted and raved. Other critics experienced no greater success, because they tried to oppose the proven facts and categorical arguments by simply denying them. Just read what they published. You will find plenty of proof of their ignorance and lack of serious observation of the phenomena, but you will never find a peremptory demonstration of their impossibility. Their entire argument may be summed up as: “We do not believe, therefore it does not exist; all those who believe are crazy; we are the only ones privileged with reason and common sense.” The number of converters won by serious or farcical criticism is incalculable because they never encountered anything but personal opinions devoid of proof to the contrary. Let us proceed with our exposition.
Communications by means of raps were slow and incomplete; it was then discovered that when a pencil was fitted to a movable object such as a tiny basket, a planchette, etc., upon which the medium placed his or her fingers, the object began to move and trace out characters. Later still, it was realized that these objects were mere accessories and could be eliminated; experience demonstrated that if a spirit  could act upon an inert object to guide it at will, it could also act upon an arm or a hand in order to guide the pencil. This led to writing mediums, i.e., persons writing unintentionally under the impulse of spirits, for whom they acted as instruments and interpreters. From that moment onward, the communications no longer had limits and the exchange of thoughts could occur with as much speed and development as among the living. A vast field was opening up to exploration; a whole new world was being discovered: the world of the invisible, just as the microscope had discovered the world of infinitely small.
Well, what were these spirits, after all? What role did they perform in the world and universe? Why were they communicating with mortals? Such were the first questions to try to answer. The spirits themselves soon stated that they were not separate beings in creation but were the actual souls of those who used to live either on the earth or on other worlds; that these souls, after having gotten rid of their corporeal envelope, inhabited and traveled space. There was no room for doubt when among the spirits we recognized our own relatives and friends, with whom we could communicate; when these spirits proved their existence by demonstrating that the only thing dead about them was their body, hat their soul or spirit continued to live and that they were right beside us, watching and observing us as they did when alive, surrounding with solicitude those whom they loved, and whose memory was a sweet happiness for them.
 We have used the pronoun ‘it’ when the referent is an ‘intelligent being’ without any gender specification, but the relative pronoun ‘who’ (instead of ‘which’) when the referent is the spirit of a human being, with free will. – Tr.
Source: Spiritism in its Simplest Expression – Allan Kardec