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 stateappointed
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.