Du Prel, Baron Carl (1839-1899)

German philosopher, author of Die Philosophie der Mystik (1885), translated as The Philosophy of Mysticism (2 vols., 1889), dealing with latent human powers, the phenomena of dreams, trance, and hypnotic sleep. Du Prel conducted many experiments on the phenomena of hypnotism (then known as animal magnetism ) before investigating the newer fields of Spiritualism and psychical research.

He investigated such famous mediums as John Eglinton and Eusapia Palladino and concluded that the phenomena of Spiritualism furnished empirical evidence of the existence of transcendental beings. He also accepted that belief in human survival was justified by his research.

However, he laid himself open to criticism by his argument that comparisons between mediums and conjurers were fallacious. His treatise Ein Problem für Taschenspieler emphasized that skilled conjurers had declared mediums they had investigated to be free from imposture. He neglected to note that conjurers had also exposed fake mediums. Du Prel's defense of psychography (slate writing ) did not incluce the techniques used by fraudulent mediums. According to Du Prel:

"One thing is clear, that is, that Psychography must be ascribed to a transcendental origin. We shall find (1) that the hypothesis of prepared slates is inadmissible. (2) The place on which the writing is found is quite inaccessible to the hands of the medium. In some cases the double slate is securely locked, leaving only room inside for the tiny morsel of slate pencil. (3) That the writing is actually done at the time. (4) That the medium is not writing. (5) The writing must be actually done with the morsel of slate, or lead pencil. (6) The writing is done by an intelligent being, since the answers are exactly pertinent to the questions. (7) This being can read, write, and understand the language of human beings, frequently such as is unknown to the medium. (8) It strongly resembles a human being, as well in the degree of its intelligence as in the mistakes sometimes made. These beings are, therefore, although invisible, of human nature or species. It is no use whatever to fight against this proposition. (9) If these beings speak, they do so in human language. If they are asked who they are, they answer that they are beings who have left this world. (10) Where these appearances become partly visible, perhaps only their hands, the hands seen are of human form. (11) When these things become entirely visible, they show the human form and countenance…. Spiritualism must be investigated by science. I should look upon myself as a coward if I did not openly express my convictions."

Du Prel also claimed to know three private mediums "in whose presence direct writing not only takes place inside double slates, but is done in inaccessible places."

We know that conjurers can fake spirit messages on slates under conditions that seem to preclude trickery, and the whole phenomenon of slate writing remains questionable. In spite of his credulity on the issue of slate writing, Du Prel declared his belief in the reality of Spiritualist phenomena. He was also ahead of his time in recommending psychical research by state-appointed and paid commissions.

Other publications by him include Studien aus dem Gebiete der Geheimwissenchaften (2 vols., 1890, 1891) and Die vorgeburtliche Erziehung als Mittel zur Menschenzüchtung (1899). He contributed to such journals as Die Übersinnliche Welt.