All human beings dream, as do all animals on the higher rungs of the evolutionary ladder. A dream is an imaginary experience while sleeping of a mostly optical and acoustic nature. As ambiguous is the reference book definition, as terse is the entry in the specialist dictionary. Here we can read that from three to six dream phases occur every night, that each lasts between 5 and 40 minutes, that they are accompanied by a slight tenseness of the muscles, irregular breathing and sexual excitation and that half of the contents of dreams are extracts from the day before, so-called remainders of the day. The history of the human culture reflects a wide variety of attitudes to dreams. Held in high esteem in archaic cultures, the subject of learned essays and discussions in classical antiquity and encyclopaedia like "dream almanacs" in the Middle Ages in Europe, today the dream is the subject of numerous scientific disciplines, from neurology to depth psychology – and it still remains a mystery.

Expression of the unconscious

The world of dreams was the domain of Sigmund Freud and his one-time pupil, Carl Gustav Jung. Both psychologists treated the dream as a meaningful product of the psyche, an expression of the unconscious part of the mind, which was amenable to and worthy of interpretation. But while Freud saw the dream as a product of sexual desires and based his interpretations on this aspect, it appeared to Jung to be rather "an involuntary psychical act [...], a specific functioning that is quite independent of will or desire, of the intention or aim of the individual," but one that confronted the dreamer with hitherto unconscious content using an encrypted language whose basic structure is archetypal.

The name of Carl Gustav Jung (1875–1961) is closely linked to ETH Zurich. He was Professor of Psychology here from 1933 to 1941, awarded an honorary doctorate in 1955 and between 1932 and 1958 he corresponded regularly with ETH Physics Professor Wolfgang Pauli, who was his patient for four years. Today, with around 1,000 manuscripts and over 30,000 letters, the ETH library houses the greatest collection of Jung documents anywhere in the world.

Discoveries while nodding off

Jungian psychology is also at the core of a PhD thesis, recently published in book form by "ökom" in Munich (1) entitled "Soil Sciences and the Unconscious" that claims to be "a contribution on the unconscious of the natural sciences." Many a searching scientist has had a surprise encounter with his or her unconscious. It suddenly dawned on me, or it was the solution to the problem," writes the author, environmental scientist, Nikola Patzel. He goes on to list scientists who made decisive steps towards their discoveries while nodding off at their desks or in their dreams. For example, Carl Friedrich Gauss who, in this manner, discovered the law of reciprocity of quadratic residue, Henri Poincaré automorphic functions, Otto Loewi acetylcholine as a neurotransmitter, Dmitri Mendeleev the periodic table of elements and August Kekulé the formula structure of benzol. According to Patzel such events show that "impulses arising from the unconscious play an important part in the flashes of recognition granted to creative scientists."

"The chemical husbander" (1855): Farming pastoral, a man resting on sacks of bone-meal and guano in a field. The centre panel underneath depicts lamps, scales and chemists' shelves and the adjoining panels laboratory items, owls, monkeys and dwarf-sized workers, busy with the "practice of science". At the bottom human bones are being excavated. The banderole above this title page illustration says, "All depends on God's blessing". large

But let's turn the clock back on Patzel. This citizen of Saarbrücken has been interested in psychology for many years. Already as a young adult he started to keep notes of his own dreams in a diary on his laptop and pondered their interpretation. After basic higher education at the Leibniz College in Tübingen he took up his studies in environmental sciences at ETH Zurich in 1992. During his second semester, in 1993, his eye was caught by an announcement for a course of lectures entitled "Archetypal dreams on environmental problems". The lectures are regularly given by Theodor Abt, Professor of Rural Sociology at ETH Zurich and member of the board of directors at the Research and Teaching Centre for Depth Psychology according to C. G. Jung and M. L. von Franz in Zurich.

The "inner soil" influences the natural scientists, says 33-year old Nikola Patzel.

"The idea that environmental sciences also took note of dreams with regard to environmental problems and research fascinated me," Patzel remembers. "By their very nature environmental problems aren't merely scientific problems but are concerned with problems in the affairs of the everyday world, which can only ever be partially addressed and solved with 'scientific', even less by 'natural scientific', means and methods", he wrote a little while later in an essay for the specialist magazine "Gaia" (2). The essay was a continuation and further development of his written semester work in which he analysed the dreams of students in their fifth, seventh and ninth semesters of environmental studies. Patzel's conclusion is that "dreams are the occurrence of events in the unconscious when problems are being processed." By acknowledging the existence of such a dream and by granting it room in our conscious thoughts we are able to step away from them, to put a certain distance between them and "ourselves", which can be important when it comes to judging one's own work. If it then becomes possible to recognise and come to terms with our dreams – recognising them as communications addressed to ourselves – the insights thus gained take on a certain autonomy in the ups and downs of our daily lives and can become superposed anchorage points for future orientation.

Beware of the glorification of dreams

An unusual statement from a scientist. It promptly provoked a cutting reader's letter. "The simple fact that something is dreamt and arises from the unconscious does not give the dream any public relevance beyond its private meaning to the dreamer ," criticised Wolfgang Giegerich, former professor of literature at Rutgers University in New Brunswick, N.J., Jung analyst and writer in Upper Bavaria on lake Wörth (3). He fears that such a view leads to the "glorification of dreams". In a reply to this in the same issue of "Gaia“ ETH Professor Theodor Abt resolutely rejects Giegerich's apprehensions. "The interpretation of dreams is indeed a question of judgment and depends on the system of values held by the interpreter. [...] If, via the environmental sciences, the disturbed relationship between human beings and nature is to be restored to an even keel, it seems to be less than opportune to exclude this reaction from the depths of our psyche merely because of difficulties in the art of interpreting of dreams," he writes.

Nikola Patzel does not want to – nor will he – argue off the cuff. "I've noticed that there is something in dreams that, for scientific reasons, I don't want to ignore. And I don't want to approach environmental depth psychology as a researcher totally uninitiated but with help of solid specialist education and training – exactly as I did at ETH with my course of studies in environmental sciences," he says. This is why, in 1996, he decided to take up studies at the Research and Teaching Centre for Depth Psychology according to C. G. Jung and M. L. von Franz in Zurich, simultaneously deepening his studies in soil science and the analysis of material fluxes. Patzel concluded his ETH studies in 1998 with the distinction of summa cum laude. For the best final degree in his year he was awarded the Willi-Studer Prize. His diploma thesis is devoted to the subject of "Soil fertility – phenomenon and concept". He also took up the idea of dreams and the unconscious in this work. Five years later his PhD thesis, "Environmental Sciences and the Unconscious", followed, now available in book form.

Inner and outer worlds

"Every one of my four supervisors was interested in and open to my ideas," says Patzel, looking back. He enjoyed great support throughout, namely from Peter Baccini, ETH Professor of Resource and Waste Management, Ulrich Müller-Herold, Professor of Theoretical Chemistry, Hans Sticher, emeritus ETH Professor of Soil Chemistry and, of course, from Theodor Abt, who has already included elements of the dream in his own doctoral thesis by attempting "to present both outer and inner worlds as aspects of a reality and show their reciprocal relationship," as Abt himself writes.

Comprehensive soil quality (1994): "Soil Quality with terrestrial globe". large

"A fundamental problem when it comes to scientific consideration of inner pictures is that their dimension seems to be completely separated from the natural science world and have thus become, from a scientific point of view, either 'nothing' or 'something different' ", thinks Patzel. "The crux of the matter is similar to that that exists between science and religion – a problem that is usually resolved by denigrating one side or the other or by a "put-them-in-a-box" attitude." The potential for deception of these inner pictures is too dangerous and their potential to enhance our knowledge too valuable to continue to turn our backs on them. "It turns out that the soil sciences," writes Patzel, "did not arise solely as subjects of strict scientific research but also as a personal interpretation of collective spiritual images, allied here to the soil."