C. G. Jung and Mediumship – from Helly Preiswerk to Depth Psychology

Published on 2026-05-15 · 11 min read

Carl Gustav Jung (1875–1961) was no late-life esotericist. His entire psychiatric career began with the meticulous observation of a 15-year-old medium: his cousin Helene "Helly" Preiswerk. The séance protocols became his Basel medical dissertation in 1902 – and from those findings later grew the theory of complexes, the collective unconscious and the archetypes. Without mediumship, Jung himself said, analytical psychology in its present form would not exist.

A family on the edge of the spirit world

Jung grew up in a family in which the paranormal was everyday. His mother Emilie Preiswerk reported being visited by spirits at night. Her father Samuel Preiswerk – theology professor and antistes of the Basel Reformed Church – was so convinced of the reality of spirit phenomena that as a child his daughter Emilie had to sit behind him while he wrote his sermons: so that the devil could not look over his shoulder. This atmosphere shaped young Carl Gustav long before he had ever seen a single patient.

Two unexplained incidents in the family home (1898)

In the summer of 1898, when Jung was 23 and a medical student in Basel, two incidents occurred at home that he could not let go of scientifically. A heavy, old dining table split right across the surface with a loud crack – without any apparent cause, without a temperature change. A few weeks later a bread knife in a locked cupboard burst into several cleanly separated pieces. Jung had the knife examined by a knife maker, who replied that there was no conventional explanation. These two "poltergeist" incidents, as he himself called them, were the immediate impetus for him to approach the subject medically and scientifically.

The séances with Helly Preiswerk (1894–1899)

From the mid-1890s onwards Jung initiated a small sitting circle within the family: glass tipping, table tipping, later trance. At its centre was his maternal cousin Helene Preiswerk – "Helly", around 15 at the start. Jung was no passive observer. He kept records with the precision of a physician, documented voices, trance personalities and content, brought in additional observers.

In trance Helly spoke as a more mature, dignified woman who called herself "Ivenes" – with a different vocabulary, a different diction and a family history that had little to do with Helly's middle-class everyday life. Other trance personalities appeared as well, some with their own voices and biographical details. Precisely this observation – that a single person can manifest several coherent, self-contained personalities – would become Jung's lifelong research motive.

The 1902 dissertation

The protocols became Jung's 1902 medical dissertation at the University of Basel: On the Psychology and Pathology of So-Called Occult Phenomena. In the same year he took up his position at the Burghölzli psychiatric clinic under Eugen Bleuler. For reasons of discretion he anonymised Helly as "Miss S. W." and altered family-historical details to protect her identity in the small Basel society of the time.

The work is methodologically remarkably modern: date of session, observed phenomenon, content, hypothesis – column by column. In substance the dissertation broke with two camps at once.

What Jung observed – and how he interpreted it

Against the classical Spiritualists: Jung did not claim that the voices coming through Helly's trance were authentic deceased persons. Against the strictly materialist psychiatry of his time: he also did not claim that it was fraud. What manifested in the trance he read as autonomous part-personalities of Helly's own psyche – "complexes" so independent, so self-contained and at times so seemingly mature that to those involved they had to feel like spirits.

This was the birth-hour of several later concepts:

  • The concept of the complex as the central unit of depth psychology.
  • The "mythopoetic" power of the unconscious – the thesis that the psyche can create autonomous figures.
  • In embryonic form: the later theory of the collective unconscious and the archetypes (Anima, Animus, Shadow, Self).
"The spirits a medium believes she hears are in reality autonomous part-souls of her own unconscious – but that does not make them less real."

From 1913 onwards: Jung becomes his own medium

After the break with Sigmund Freud (1913) Jung went through an intense phase of self-experimentation: deliberately evoked inner images, voices, dialogues. From these sittings with himself emerged the figures that mark his later work – Philemon, Salome, Elijah. Sonu Shamdasani, the editor of the Red Book (Liber Novus, 2009), reads this phase as the direct continuation of the Helly protocols: Jung was now doing himself what he had recorded with his cousin two decades earlier – only that he remained fully conscious and later called the procedure active imagination. The Red Book is the calligraphic and painterly elaboration of these inner journeys.

1916: The "Septem Sermones ad Mortuos"

In January 1916 Jung reported a peculiar atmosphere in his house in Küsnacht. It was "full of spirits", the whole family felt it, doors slammed, an oppressive tension filled all the rooms. Only when Jung sat down and began to write did the atmosphere disappear. The result was the Septem Sermones ad Mortuos – "Seven Sermons to the Dead", a Gnostic text in archaic diction. Jung himself later described the event as a real paranormal experience, not as image or allegory.

His later position: measured openness

Jung remained carefully two-track throughout his life. In public he generally explained paranormal phenomena psychologically: as "exteriorisations" of unconscious complexes, as manifestations of the collective unconscious. In private he later wrote that he had experienced so many paranormal phenomena that he was "convinced of their reality" – it was just that the scientific proof was difficult to produce.

The late theory of synchronicity (developed from the late 1940s with the physicist Wolfgang Pauli) is Jung's attempt to give that tension a conceptual frame: non-causal but meaningful connections between psyche and world. It is a consistent extension of the line he opened in 1902 with Helly Preiswerk.

The family's criticism

In 1975 the book C. G. Jung's Medium. The Story of Helly Preiswerk by Stefanie Zumstein-Preiswerk – a relative – appeared. The core criticism: Jung had pathologised the Spiritualist side of his cousin too quickly, had translated the meaning of the phenomena too early into a psychological model, and had thereby also damaged Helly personally. In the small society of Basel she was known after the publication of the dissertation as "the mentally ill one in the family". Helly Preiswerk died in 1911 at only 30. This criticism is part of the picture; without it, Jung's relationship to mediumship is not fully told.

Why Jung matters for mediumship

  • Academic recognition as a research subject. With Jung, mediumship was for the first time treated systematically at a medical faculty in the German-speaking world – not as esoterica but as data.
  • A bridge instead of a front line. Jung remained between Spiritualism and materialism and thereby created the language in which the subject can be discussed at all today: complex, archetype, synchronicity, collective unconscious.
  • Depth psychology out of the séance protocol. Without Helly Preiswerk no analytical psychology in its present form. Jung said so himself, repeatedly.
  • Continuity with later research. The line runs from Jung onwards into present-day experimental work – see our articles on Gary Schwartz / VERITAS, Julie Beischel / Windbridge and the Tressoldi meta-analysis.

For the broader biographical frame, see our article on Mediumship in Switzerland – there Jung stands alongside Paracelsus and the old Alpine healing tradition as the academic bridgehead of the 20th century.

Sources

  • C. G. Jung: Zur Psychologie und Pathologie sogenannter occulter Phänomene. Dissertation, University of Basel, 1902 (available online).
  • C. G. Jung: Memories, Dreams, Reflections. Recorded and edited by Aniela Jaffé, Rascher / Pantheon, 1962 – including the report on the 1898 incidents and the 1916 Sermones episode.
  • C. G. Jung: Liber Novus. The Red Book. Edited and with commentary by Sonu Shamdasani, W. W. Norton, 2009.
  • Stefanie Zumstein-Preiswerk: C. G. Jungs Medium. Die Geschichte der Helly Preiswerk. Kindler, Munich, 1975.
  • Sonu Shamdasani: Jung and the Making of Modern Psychology. The Dream of a Science. Cambridge University Press, 2003.