The spirit acquires an increase of knowledge and experience in each of his corporeal existences. He loses sight of part of these gains during his reincarnation in matter, which is too gross to allow of his remembering them in their entirety; but he remembers them as a spirit. It is thus that some somnambulists give evidence of possessing knowledge beyond their present degree of instruction, and even of their apparent intellectual capacity. The intellectual and scientific inferiority of a somnambulist in his waking state, therefore, proves nothing against his possession of the knowledge he may display in his lucid state. According to the circumstances of the moment and the aim proposed, he may draw this knowledge from the stores of his own experience, from his clairvoyant perception of things actually occurring, or from the counsels which he receives from other spirits; but, in proportion as his own spirit is more or less advanced, he will make his statements more or less correctly.
Allan Kardec