At this point, Allan Kardec became a witness, and while skeptical at first, he eventually became a serious student of these Spirit communications which, by the way, took on an especially serious, intelligent, and moral nature when he was present

The Spirits revealed that they were not a separate class of beings in creation, but the souls of those who had lived on Earth or other worlds…. now free of the material body and able to move freely through space. 

Kardec was very careful, for he soon recognized that in such case, each spirit's knowledge would be limited to it's own level of advancement, and must be observed with caution. He himself wrote, "………. avoiding preconceived notions, I observed attentively, compared observations and deduced the consequences. I tried to identify the causes of the phenomena by linking the facts logically, and I did not accept an explanation as valid unless it could resolve all the difficulties of the question." 

In other words, he applied the numerous spirit communications- received from various places around the world- to systematic and methodic analysis, cross-examination (to test for universality of general knowledge and agreement of teachings from Spirits of a superior order), and other tests of logic and reason.  The science of Experimental Spiritism was born. 

The first questions that needed to be addressed were: What are these Spirits? What is their role in the Universe? To what end do they communicate with us mortals? The answers to those questions brought serious proof as to not only the existence of the soul, but also of the soul's survival of death and continued individuality thereafter.  

The facts themselves, Kardec writes, "fall into 2 categories: those that are spontaneous and those that are provoked. Among the former are the visions and apparitions; the noises and movement of objects without a material cause; and a great number of uncommon effects that we used to look upon as supernatural. The latter are those obtained through mediums."

In that category of mediumistic "data" if you will, were included communications that came with information about people, places, and times often previously unknown to anyone present, sometimes in languages completely unknown to the medium, and even cases where written message were received in the medium's native language despite the fact that that particular medium was actually illiterate! 

Now, the science of Experimental Spiritism began to emerge in it's true role, which Gabriel Delanne   states (in "O Fenomeno Espirita" -Spiritist Phenomena) as, "a science, whose purpose is the experimental demonstration of the existence of the soul and its immortality, by way of the communication with those who we inappropriately call 'the dead'." [quotation as cited by Barbosa]   In these communications, the spirits began to reveal not just that their existence as spirits meant that they were the souls of men, but they also told about the habits and behaviors that they had on Earth and in past lives, and to what state that had brought them in the present, thereby revealing, in detail, the kinds of suffering or rewards that result from the choices we make in using our free will.

As one can imagine, each new piece of information revealed only brought more philosophical questions… resulting in a collection of information so significant that Kardec (as he was instructed by the Superior spirits to do) published these questions and answers in the first book of the Doctrine's codification …. "The Spirits' Book".

Spiritist Science, however, did not end there. This practice of observation and analysis continued and is still alive and active today, and we continue to learn more about the nature of our world and the divine laws under which it is governed.

Kardec, Allan. Christian Spiritism (a compilation of two Kardec books: Spiritism Reduced to Its Simplest Expression and What is Spiritism).  Trans. Allan Kardec Educational Society (translated from original French editions, published 1860 and 1859, respectively). Philadelphia, PA. Allan Kardec Educational Society. 1985. 4; 59; 193-195.

Barbosa, Pedro Franco. "O Espiritismo Cientifico" [Scientific Spiritism] Espiritismo Basico [Basic Spiritism]. 3rd ed. Rio de Janeiro-RJ, Brazil: Federação Espírita Brasileira [Brazilian Spiritist Federation].1987. 105-106.