How did Allan Kardec use mediums’ answers in writing The Spirits’ Book?

To write The Spirits’ Book, published in 1857, Allan Kardec utilized a systematic, analytical approach to the information he gathered from mediums across Europe.

Kardec posed a series of philosophical questions to these mediums, seeking insights into the nature of the spirit world. He then collected and analyzed the resulting responses, which were believed to originate from spirits. To ensure the reliability and consistency of the doctrine, Kardec included these responses in his foundational text only if he determined they were corroborated by other responses he had received. Through this method, he aimed to apply a sense of scientific skepticism and empirical analysis to the movement, framing his work as a "Positive Faith" that bridged the gaps between science, philosophy, and religion.1