Modern systems: close reading

Carl Jung and alchemy:
projection, Mercurius, evidence

Carl Jung (1875-1961) read European alchemy as psychology: alchemists, he argued, projected unconscious processes onto the matter in their vessels, and their stages mirror what he called individuation. Historians of science grant his influence and reject his history of alchemy.

What did Jung say alchemy was really about?

Jung said the alchemical work dealt less with chemical experiments than with “psychic processes expressed in pseudochemical language”: the alchemist, he argued, experienced his own unconscious as a property of matter (Collected Works 12, pp. 242-254).

He did not deny the laboratory; he took the way recipes varied from author to author as the sign of projection. The goal was individuation: growth of a new centre of personality, the self, holding conscious and unconscious. His readings of single images are in the table below.

When did Jung start studying alchemy? A dated timeline

Jung’s turn to alchemy is usually dated to 1928, when Richard Wilhelm (1873-1930) sent him a Chinese alchemical text, but he had already used images from the alchemist Zosimos in 1912 (Silveira, 2025).

In English: Collected Works 12, 13, 14 and 16 (from 1953; editions cited here: Princeton, 1966-1970).

What is the Rosarium philosophorum, and why did Jung use it?

The Rosarium philosophorum (Rosary of the Philosophers) is an anthology of alchemical sayings printed in Frankfurt in 1550 by Cyriacus Jacobus, with woodcuts of a king and queen who unite, die and are reborn.

It is the second part, with its own title page, of De alchimia opuscula complura veterum philosophorum; a public-domain scan is at the University of Wisconsin-Madison. In 1946 Jung used ten of its pictures, from the “mercurial fountain” to the “new birth”, to describe transference, the bond between patient and doctor (Collected Works 16, pp. 203-320). The naked king and queen of the third picture stand, for him, for the conscious mind meeting its shadow.

One trap: the printed Rosarium is not the medieval Rosarius that circulated under the name of Arnau de Vilanova, and neither text is his.

Who is Mercurius in Jung’s alchemy?

Mercurius is the alchemists’ name both for quicksilver and for a living spirit in matter; Jung read him as an image of the unconscious and of the self, and as the alchemical heir of Hermes.

In his essay on the spirit Mercurius, first given as an Eranos lecture in 1942 (Collected Works 13, pp. 191-250), Jung starts from the Grimm tale The Spirit in the Bottle, names quicksilver as the first meaning, collects names for a figure both god and devil, and calls the airy Mercurius the counterpart of Hermes and the Egyptian Thoth (IAAP abstracts).

Jung reaches Hermes through the alchemists: his oldest source for the stone-Christ parallel is the Tractatus aureus, ascribed to Hermes and held to be Arabic already in the Middle Ages (CW 12, pp. 358-360). His Hermes is the patron of alchemy (our reading).

What do historians of science say against Jung?

Historians of science, led by Lawrence Principe and William Newman (2001), argue that alchemists did real laboratory chemistry, and that reading all of alchemy as spiritual took its full form only in 19th-century occultism, which shaped Jung.

• Before Jung. Mary Anne Atwood (London, 1850); Ethan Allen Hitchcock (Boston, 1857), whose title denies that the stone was sought to transmute metals.
• Its source. Principe and Newman: Jung and Mircea Eliade were “directly influenced by late nineteenth-century occultism”; splitting spiritual alchemy from chemistry is “an ahistorical formulation” (2001, quoted by Călian, 2010).
• The images decode. In George Starkey (17th century) the “net of Vulcan” is a recipe: Vulcan is fire, Mars iron, Venus copper, the net a purple copper-antimony alloy, which Isaac Newton made in his laboratory (Newman, 2015).

The other side: Călian (2010) notes that the critique does not fully undermine Jung’s work, whose aim was psychological, not historical. And Mike A. Zuber (2021) traces a spiritual alchemy of rebirth from the mystic Jacob Boehme (1619-1622) to Atwood and, through her, to Jung: one current, not all of alchemy, but older than the 19th century. The same images, read two ways:

Our view: Jung is a good guide to Jung, a poor one to 16th-century alchemists; we read him as reception, as on the Great Work.

Is there scientific evidence for Jung’s alchemy?

We found no study that tests Jung’s alchemical theory itself, and its basis, inherited archetypes, still lacks “firm scientific foundation”, as a Jungian author concluded in 2012; nearby practices have some evidence.

• Roesler, 2012. No firm evidence that complex symbolic patterns, such as the hero myth, are passed on to every person. Not a disproof; universality is simply not shown.
• Roesler, 2013. Jungian therapy studies, mainly German and Swiss: patients improved, gains held up to six years, after 90 sessions on average. The author, a Jungian, notes there is no randomised trial, so no proof of efficacy; and it tests therapy, not reading alchemy.
• Frattaroli, 2006. Meta-analysis of 146 randomised studies of disclosing thoughts and feelings on personal topics: a positive but small average effect (r = .075).
• Lieberman and colleagues, 2007. Naming a feeling damped the amygdala’s response to negative images. A short lab effect, not a treatment.

Projection in dead alchemists cannot be tested; their recipes can (Newman, 2015).

What can you try for five minutes? Separate the vessel from the projection

Write down one image from a dream or your day, split it into what was there and what you read into it, and ask what your reading points to: projection as a reading tool, not therapy.

1. One image (1 minute). One line, plain words, no meaning yet: a dream scene or a moment that stuck.
2. Name the feeling (30 seconds). One or two words. This step is closest to a lab finding (Lieberman, 2007).
3. Two columns (2 minutes). “In the vessel”: only what you saw or heard. “What I put in”: your reading, guesses, fears.
4. One question (1 minute). “What does my reading point to that I have been avoiding?” One line.
5. One check (30 seconds). One small thing to check or do today, or “nothing yet”.

Example.
Image: a dream, my old desk in a locked lab. Feeling: dread.
In the vessel: a door, a desk, I could not get in.
What I put in: I am shut out of work that was mine.
Avoiding: asking for the analytics project back.
Today: one email asking my manager for 15 minutes on Friday.

Why it might help. It does what historians do with alchemical texts: separates the material from the reading. Putting feelings into words helps a little on average (Frattaroli, 2006); the split itself is untested. No symbol dictionary, no predictions. A chatbot telling you what your dream “means” is someone else filling your second column (see cognitive offloading).

Where it stops. If an image brings back a traumatic memory, stop and do not push it. If nightmares, low mood or anxiety last for weeks, see a doctor or a licensed therapist; in a crisis, call your local emergency number.

What does this not promise?

Neither Jung’s alchemy nor the exercise promises transformation, gold, healing or a finished self; at best you learn to notice what you read into things.

• Not proof of archetypes, or of Jung’s history of alchemy.
• Not therapy. Jungian therapy is done with a trained analyst, over many sessions.
• Not “your nigredo phase”. Stage maps on blogs quote Jung, not the alchemists.
• Not a verdict on Jungian analysis or on anyone’s faith.

Where does Jung stand on the line from Hermes to today?

Jung stands at the psychological end of a line of borrowing: Hermes as patron of alchemy, laboratory alchemists, a spiritual reading that runs from the age of Jacob Boehme (around 1600) to its 19th-century occult form, and then Jung, who turned that reading into a clinical method.

Zosimos of Panopolis (c. 300) is the first alchemist about whose life anything is known; the Emerald Tablet, a short text under Hermes’s name, oldest in Arabic, gave later alchemists a motto. Paracelsus (1493/94-1541) put alchemy to work for medicine; the Rosarium was printed in 1550; Atwood (1850), drawing on an older spiritual alchemy, and Hitchcock (1857) read it as an inner art; Jung made it psychology in 1944. On our Modern systems line he is reception: alchemists asked how matter changes, Jung how a person changes. The old text is the source of the question, not proof; to date a claim, ask for the date.

Key facts

Who	C. G. Jung (1875-1961), Swiss psychiatrist
Main books	Psychologie und Alchemie (1944); Mysterium coniunctionis (1955-1957)
First contact	Zosimos imagery in 1912; usually dated 1928
Core claim	Alchemists projected the unconscious onto matter
Picture source	Rosarium philosophorum, Frankfurt 1550
Historians	Purely inner alchemy is a modern reading (Principe and Newman; Zuber)
Evidence	Archetypes not established; putting feelings into words helps a little
Checked	13 November 2026

Fair questions

What did Carl Jung think alchemy was?

Jung thought alchemy was less about chemistry than about “psychic processes expressed in pseudochemical language”: alchemists, he argued, projected their unconscious onto the matter in their vessels, and their stages mirror individuation.

When was Psychology and Alchemy published?

In German as Psychologie und Alchemie (Zurich: Rascher, 1944); its themes go back to Jung’s Eranos lectures of 1935 and 1936. In English it is volume 12 of the Collected Works.

Who is Mercurius in Jung?

Mercurius is the alchemists’ quicksilver and a spirit hidden in matter. In an essay first given as a lecture in 1942, Jung read him as an image of the unconscious and the self, and as the counterpart of Hermes and Thoth.

Was Jung right about alchemy?

As history, mostly not: Principe and Newman (2001) argue that alchemists did real chemistry and that reading all of alchemy as spiritual took its full form in 19th-century occultism; Zuber (2021) traces a smaller spiritual current back to around 1600. As a psychological reading of old images, it is a 20th-century reception in its own right.

How does alchemy relate to individuation?

For Jung, the alchemical sequence (blackening, union of opposites, the stone) was a picture of individuation, the growth of a self that holds conscious and unconscious. The link is his interpretation, not something alchemists wrote.

Sources & further reading

• Records: Library of Congress 1929, 1942, 1944, 1955-1957; Deutsche Nationalbibliothek 1946. Records only.
• IAAP abstracts of the Collected Works: vol. 12, 13, 14, 16 (read 12 November 2026); Jung quoted from them.
• Eranos dates: R. Bernardini, Jung a Eranos (Milan, 2011), contents; C. Wagner, PhD thesis (Cambridge, 2018), abstract.
• F. Lopes da Silveira, “Before the Golden Flower”, Journal of Analytical Psychology 70(2), 2025, abstract.
• Rosarium philosophorum (Frankfurt: Cyriacus Jacobus, 1550), UW-Madison scan, public domain.
• Atwood 1850 (scan), Hitchcock 1857 (scan), Silberer 1914 (scan): titles and records; Silberer checked for content.
• W. R. Newman, “The Problem of Alchemy”, The New Atlantis 44 (2015), PDF.
• Principe and Newman, “Some Problems with the Historiography of Alchemy” (MIT Press, 2001, LoC), quoted from G.-F. Călian, Annual of Medieval Studies at CEU (2010), PDF; chapter not read.
• M. A. Zuber, Spiritual Alchemy: From Jacob Boehme to Mary Anne Atwood (New York: Oxford University Press, 2021), abstract (read).
• Abstracts read: Roesler 2012, 2013; Frattaroli 2006; Lieberman and colleagues 2007.