An active fantasy about the unconscious
Dedicated in friendship to Miss Dr. Marie-Louise v. Franz
Translated from the German by Frederik W. Wiegel,
Herbert van Erkelens and Jos van Meurs.
Harvest. Journal for Jungian Studies, Vol. 48 No. 2, 2002.
It was a misty day and I had been seriously troubled for quite some time. There were namely two schools: in the older school they understood only words but not the meaning. In the modern school they understood the meaning, but not my words. I could not bring the two schools together.
I thought my last hope was to visit a girl who lives in Küsnacht. The address was Hornweg 2, simply two – not the Golden Horn which I visited once before. There was so much about which the girl could not speak; this pleased me much for it would enable me to imagine it in such a way that it could not be very different from my own troubles and that therefore she would certainly understand me.
So I arrived at Hornweg 2 in Küsnacht and I opened the door. Then I heard from a distance the firm, masculine voice which I know so well and which always sounds like the voice of a ship’s captain. It said ‘Time reversal‘ and I saw his (the master‘s) images, which looked like conical paper bags pointing downwards with their openings upwards, and made of some overlapping sheets.
The master’s voice and his images gave me great confidence. I went into the house, entered the room and —
I was in Vienna. I was a schoolboy who held a map with sheets of music in his hand. I knew clearly that we were in the year 1913, but it was the year 1913 on another sheet of the conical bag, namely on that sheet on which I could also still remember the house at Hornweg 2 in Küsnacht. The room contained a grand piano and other pieces of furniture, as in the old days. A lady leaned against the grand piano, her hair was dark and she was like a trusted old friend. She was a distinguished lady and I felt I should address her with great respect. When I approached her at the piano she held out her hand to me and said: ‘You have not played the piano for a long time. I will give you a lesson.’
I answered: ‘I am looking forward to this lesson; tones would really be very lovely now, for I am greatly troubled. Moreover, I used to know a girl who must also have felt greatly troubled. I knew this because she once said to me: ‘My mother has destroyed my femininity.’ But I could not believe her: how could my feelings be touched by something which has been destroyed?’
The lady gave me a friendly smile and said to me as if she was speaking to a schoolboy: ‘No, that is impossible. But it might be possible that things have not been true which earlier on were quite self-evident, just when you had your little thoughts.’ And I played a normal C major chord C E G. Like an inquisitive child I shouted: ‘I would like to know what really happened’, but this the lady did not know either.
After a while I heard another command coming from a great distance; the master said clearly: ‘Captain.’ I did not understand this at all. The lady, however, jumped up from her chair and paced a few times up and down the room, all in a flurry. Then she sat down again beside me and said: ‘I will guide your hand.’ First she let me play the minor third C E-flat, followed by A-flat C E-flat. Next came a fourth G B-flat and then she said: ‘You see, once upon a time there was a captain…’
When she touched my hand I could speak, accompanied by simple tones. And I told the following story:
‘Here in Vienna lives a captain with a daughter who is ill, her soul is ill. I can see clearly how the master approaches the captain’s house. He seems to expect the captain to speak the words.’
‘Which words?’ asked the lady, astonished.
‘The words, of course,’ and I spoke them aloud:
‘Lord, I am not worthy to receive you in my house, but speak just one word and my servant will recover’
and I played a simple chord of four notes F A C F.
There was a pause, I wiped sweat from my forehead and the lady calmed down.
After a while I started to speak again:
‘Now I remember; there was another captain in Kapernaum who spoke these words for the first time.’
‘So what used to be self-evident would not be true anymore,’ the lady interrupted.
And I continued briskly: ‘Kapernaum or Vienna does not make any difference, but the captain in Vienna did not speak the words. Mind you, all he should have changed is to say “my daughter” instead of “my servant”! I already learned in primary school – which was not a good school by the way – that one often speaks of “my soul” instead of “my servant”. But the captain in Vienna belonged to a school in which the words were understood but not the meaning, so he could not find the words when the master wanted to come. Hence the master turned round, and I see how he leaves.’
Playing a minor chord C E-flat G, I went on: ‘It must be difficult for the master to make himself known to us. And even more difficult to make himself understood by us. We are strangers to him, as he is a stranger to us. To us he looks as if he is dreaming, like a sleepwalker who is perfectly sure of himself. I believe he does not know much about our waking state, but he has a vague notion and wants to know more about it. That is why he wants his world and ours to come closer together, and this is what he is trying to arrange all the time. He does not mind turning round once in a while, yet this is serious enough to harm the captain and his daughter.’
At this point the lady cut in: ‘He is now trying something else. He told me I should help you to play the piano better. I also caught his words “through the censorship”, but this I did not understand.’
‘Oh, but I do understand that a little,’ I interrupted. ‘Do you remember Freud?’
‘He was my advocate, but he did not know it,’ the lady whispered, and I played a minor chord A C E A.
Then I continued: ‘He believed there is a censorship which is permanently there but only shows itself in dreams. He also believed that it is the product of a moralizing Victorian matron, who is invisible unless reflected in this very censorship.’
Next I turned to the lady with the words: ‘Now I want to tell you a great secret. Such a moralizing matron does not exist, but a censorship of dreams does really exist.’ And I whispered rapidly in her ear: ‘It is created by contemporary professors, in particular by those in the sciences. That is naturally the case because the captain of Köpenick has no power anymore – thank God! Save for one restriction.’ And I played first F A-flat C, then E-flat G B-flat.
The lady: ‘Whom do you mean by the captain of Köpenick?’
I: ‘All the charlatans into whose traps so many fall. Most of them have unfortunately, ah! also studied theology and they are numerous in heaven and on earth. When I was in primary school, I believed that there was no other captain than the one of Köpenick. But later I heard the more realistic judgement of an Irishman (G.B. Shaw) that the captain of Köpenick can only be possible because there exist also true captains and true masters. That convinced me immediately and since then this state of affairs has not stopped to interest me.
‘You spoke about a restriction,’ – the lady questioned me – ‘What do you mean by that?’
Without hesitation I answered: ‘In the East you find a new variant of the captain of Köpenick, a sect of virulent theologians. They are the red slaves already described by the alchemists. They are dangerous because of their guns and canons, while the old, black theologians have to do without these and also have to do without the stake.
That is of importance for understanding the dream censorship: the master sends me images of scientific meetings in Russia which take place under pressure of the police and at which the police prevents most participants from talking. Of course, the master means by this myself and in particular the generally held but quite limited current views in my mind (“theories” as the Greeks used to say).
Now that the point has been reached that the captain in Vienna has not spoken the words and the master has had to turn round – as occurs hundreds and thousands of times – the master now wants to assert himself under all circumstances and he seems to find me particularly suited for that purpose: he wants to come out into the daylight through me, at all costs! I must say, I often feel weird and I am frightened of him and apprehensive. He is not only good, but he can also be evil and dangerous. And he is most dangerous, when you try to ignore him, as the captain in Vienna has done. So on the one hand I am afraid, on the other hand he fascinates me. I can no longer keep away from him, as he can not from me.’
And I played the fourth F B-flat on a white and a black key. The lady then said: ‘My attitude towards him is just the reverse. I was in his bondage and obeyed him blindly.’ I answered her by shaking my head: ‘For a long time I used to believe that that was the right thing for you to do, but I changed my mind in this respect. – Perhaps we are both prejudiced in regard to him. A captain of Köpenick once told people that the black keys of the piano are just holes where the white keys are missing, and that all the masters are either completely white or completely black. Many people echo this.’
The lady laughed loudly and gave me a hint: ‘Tell them that you can also play minor chords on the white keys such as A C E and major chords on the black keys such as F-sharp A-sharp C-sharp. All that matters is that you know how to play the piano.’ I played faithfully and willingly as she had told. When I looked at her, I noticed that she now had slit eyes.
I continued to report: ‘Now that I realize better that the art of playing the piano is all that matters, I have considerably eased the censorship of late. The master immediately sent me images which showed the Russian armies being pushed back after heavy fighting. Later I even got images in which the Russians retreated voluntarily. The Iron Curtain in me is no longer impenetrable, there are smaller and larger gaps in it, peep-holes through which I can look. Through one of these holes I saw the captain in Kapernaum and in Vienna, after you had helped me.’
‘I see a vast mainland,’ said the lady. ‘The water has drained away, the land is still somewhat wet but it is firm ground.’ It stretches to the far north and it is inhabited by strange people.’
I continued: ‘And I see how the master distributes newspapers among the strangers. I cannot read them, but they do; these papers probably tell them their names and who they are.’
She: ‘The black keys want to contribute major chords, play F-sharp A-sharp C-sharp.’
I said slowly: ‘I have the impression that the white keys are like the words and the black keys are like the meaning. At times the words are sad and the meaning joyful, then again it is just the other way round. Here, with you, it is no longer as in the two schools which gave me so much trouble: I can always see that there is only one piano.’
In a soft voice she spoke to me: ‘I can only play the piano, I understand nothing of your numbers. But they say that the numbers follow the tones. I can now understand some of what you told me about the censorship. The censors want to understand the world without the piano music. But that is absurd! One must play differently according to how warm it is, and in accordance with how one plays it will be more or less warm. For example, a while ago it got quite hot when he said “Captain”.’
I: ‘The censors believe nowadays that chance rules the world, I mean the best of the censors. By the way, why do you play tricks on the gentlemen in France and other places? I know that you were the one who gave them these phantasms of “mosquito parameters” as I call them, which nobody can catch and which actually multiply when you try to catch them. All this is disturbing for the best and most reasonable people, since the victims of these practical jokes believe again that the world is like a clockwork which runs down automatically. You are playing a dangerous game. I know that in this case you have acted on your own, not by order of the master.’
She (feeling caught and a bit embarrassed): ‘Yes, I did. But I do not consider this game as really dangerous. I do know the name of the pitchfork used for the last 300 years to chase me out of the mountains, rivers, forests and in particular out of the heavenly spheres. But I consider this weapon against me as sufficiently blunted.’
I (laughing and trying to distract her): ‘The name is “cause“, but children already are always asking “why”?’ And I played a chord of the seventh C E G B-flat that desires to be resolved. She (quieted): ‘Yes, I have always liked children very much. But precisely because I like children, I had to take the risk of playing this game with the “phantasms” as you call them. You don’t need these images, neither do many others. But I intentionally created unrest, because people try to understand the world without the piano music. Even “the best of the censors”, as you call them, do not know that their concept of mathematical probability is that which remains when one is totally ignorant of our piano-playing. Do they believe then that chance is always the same? Doesn’t it change when it gets warm?’
I answered mindfully: ‘Chance is always fluctuating, but sometimes it does so systematically.’
With these words a big change comes about. Through the window I see people approach the house across the land that shortly before had run dry. They line up at the window and call out my name. At first their faces are unfamiliar, I do not recognize any of them. I play some Bach, to keep everything orderly.
Then the voice of the master is heard again. This time he says: ‘Younger brother!’ ‘Ah, Benjamin,’ I exclaim – that was his old nickname – and I immediately correct myself: ‘Of course, I should say: Max!’ And there he is at the window, smiling friendly at me.
For a moment I feel lifted up in the air and I saw images passing by: Max, the youngest brother of many sisters, is in Zürich, he wants to give up physics for biology. I try to press him to do so. – Then images from the master: a festive gathering in a church, the cave-salamander, orientation in the dark, owls, bats – Dijkgraf’s experiments with these. Next it is 1934 again: my old drawing of a boat which I called ‘Darwin’, because the master ordered me to do so. Dream images of biological research papers by French scientists, which I cannot read. Time runs forward: Max, the German, goes to America and takes up biology. More dream images, I must speak with him, not only with the physicists – after all he is my ‘younger brother’.
More images pass by – I am standing again on the floor of the room, this time at the window. Max signals and the strangers applaud and call my name again and again. I have no choice, I have to give a lecture. At last, I give in and open the window. At that moment I am no longer in Vienna, but instead I am in Zürich in normal time, 1953. I speak, from the window, as follows:
The lecture to the strangers
Compared with the older way of explaining nature, which assumed a detached observer and a fully deterministic course of physical events, the new physics generated a new type of explanation, its principle being “blind” chance without purpose, the primary probability which does not admit of reduction to deterministic laws. From this new way of understanding nature the primary probability is seen to be essentially related to the fact that the observer, through the choice of the experimental arrangement, intrudes into the course of events, since the measurement brings about unverifiable interactions with the object of measurement. Hence, the element of freedom in the natural course of events is stressed considerably by this point of view.
In reaction to these new insights some physicists want to return to the old ideal of the detached observer, in my opinion a negative-regressive utopia. I would like to take the opposite point of view that from these insights you can only go forwards and that this will lead you straight to the phenomena of life. Although the new physics differs considerably from the older, “classical” form of describing nature, nevertheless one finds even here implicit concessions to the traditional notion of the “objectivity” of natural laws. Once the observer has chosen his experimental arrangement, the new physics claims that the result of the observation is completely independent of his state of consciousness; he can only register, not influence it.
Hence it seems to me that an attempt to extend the viewpoints of modern science will on the one hand lead to parapsychology, on the other hand to biology. It is only there that one can expect a new, third type of natural law.
In particular I would like to ask your attention today for certain aspects of biology which show fundamental problems which have been ignored for too long.
Where in biology do we encounter chance? First of all, we must note that Mendel’s laws of heredity are statistical laws, just like the laws of quantum physics. Indeed – for the first time by M. Delbrück – statistical models have been constructed for the occurrence of mutations on basis of quantum physics, both for the spontaneous mutations which occur in a natural environment and for the mutations which under laboratory conditions are “induced” by external agents (irradiation or chemical treatment of the chromosomes). The present state of genetics seems to promise that heredity after the occurrence of a gene mutation may be understood on the basis of physical-chemical models.
But it seems to me that the theory of evolution confronts us with much deeper problems. Within this field one has tried – since the days of Darwin – to reduce the whole biological evolution to blind (i.e. purposeless) chance. This point of view is nowadays combined with the enormous progress in genetics that has been made since the time of Darwin, and is called “neo-Darwinism.” This theory assumes that biological evolution is caused exclusively by small mutational steps produced by pure chance, from which the external, environmental conditions of the species make a so-called “natural” selection.
Opposed to this is Lamarck’s view, which claims that the external conditions bring about genetic changes in the form of a purposeful adaptive response. This idea has now generally been abandoned, because attempts to produce artificially such hereditary adaptations under laboratory conditions have never been successful. These seem constantly to prove that acquired properties will not be inherited by the next generation. The objection of the “vitalists” that these experiments only fail because they are pursued for too short a time is countered by the Darwinists by pointing out with some reason that it is not the length of time that matters, but the number of generations produced during the period of observation. It is quite reasonable to expect that this question may be solved by experiments with living beings that reproduce sufficiently quickly.
On the other hand, I have heard that some highly respected and experienced researchers are of the opinion that the Darwinist attempt to explain the phenomena of adaptation by “blind” chance must equally be incomplete in some essential respect. The adaptation of the organs to the physical life-conditions can indeed hardly be explained by a purposeless chance which already before the actual realization of the external conditions has providentially brought forth among many others the one mutant that only later is adapted. Moreover, although acquired properties will normally not be inherited by the next generation, in some cases this does happen, for example, in the case of the navigation of migratory birds which must certainly have been learned at some time in the past.
One has, therefore, the impression that the external conditions on the one hand, and the genetic mutations leading to a proper adaptation on the other hand, are not connected in a causal-reproducible way, but that these mutations nevertheless emerged meaningfully and purposefully as an indivisible whole together with the outer circumstances. They correct the “blind”, random fluctuations of the mutations that spring up.
According to this hypothesis, which differs from the theories of Darwin as well of Lamarck, we encounter here the third type of natural law which we have been looking for; it assumes the correction of the random fluctuations through meaningful and purposeful coincidences that are not causally related. Although in this way the first appearance of a biological adaptation is not regarded as causal, it seems not impossible, after what has been said before, to understand the further hereditary survival of such a gene mutation – once it has “succeeded” – through models of a physical-chemical kind.
In this connection I would like to submit the further hypothesis that this holistic occurrence of meaningful coincidences in biological evolution points to a psychic factor which goes hand in hand with them and which on a higher level appears as emotionality or excitement.
I hope to return to this point of view after further study of the relevant material. The advantage of this hypothesis in my view is that it relates the phenomena of biological adaptation I have discussed to other phenomena, and thus permits to conceive a more general aspect of nature in a unified way. I have especially in mind the E.S.P. phenomena studied in particular by Rhine, in which apparently the feeling of involvement plays an essential role as an emotional factor. The absence of this factor shows up negatively as “the effect of fatigue.” I have further in mind the meaningful coincidences, brought to our attention by C.G. Jung, which cannot be reproduced intentionally and only occur in special circumstances. By naming these coincidences “synchronistic,” he acknowledged a peculiar relation between them and our notion of time. Inasmuch as the phenomena of adaptation in biological evolution clearly demonstrate a direction in time, it seems quite natural, also from this point of view, to consider all the acausal phenomena mentioned here and connected with meaning or purpose, as essentially related.
In spite of the lively calls from the audience that I should speak further, I closed the window and was alone with the lady. She said: ‘I think you have fathered a child on me. It must become a legitimate child. Do you have your passport?’
I: ‘My passport is at home and I feel that is nearby. When one really wants to introduce such a child to the people, one has to show them something they can verify for themselves. All I can tell them is that here, too, chance sometimes changes in a systematic way, but I cannot yet explain to them sufficiently the psychic reality which you indicate by the words “it is getting warm”, and certainly I cannot explain how one can intentionally influence or bring this about. That would in any case look more like what the primitives call a magical procedure than a scientific experiment. To begin with I would have to start to explain to them in a different way what is meant by piano and piano playing, because they will probably see different images and hear different tones than we do.’
She: ‘I can only play the piano and teach it. I can neither teach a theory of the piano nor can I build one.’
I: ‘A human being is like this piano: the tones have pitch and intensity, the melodies are figures which can be reproduced and recognized in different keys, because one key can be transformed into another one. Just as there are low, medium and high tones, you find in human beings the instinctive or impulsive, the intellectual or rational, and the spiritual or supernatural. The volume of sound is the intensity with which the tones act upon our consciousness.
I know that there is a school which speaks of typical, primordial images (archetypes) instead of melodies or figures, of colours in stead of pitches, and of light and heavy masses instead of small and big volumes of sound. I suppose this means the same as in our case, since the master, too, talks to me about atomic weights and spectral lines. The common feature of all these images and melodies is number – You have said earlier that you understand nothing of our numbers. Do you know any other numbers?’
She (thoughtful): ‘I am not sure, but I guess so, because numbers and tones are for me really one and the same. When the pitch is a number and the volume of sound is one, then I could actually observe them and the melody would be a “pattern” of numbers, as the English say so strikingly. But only seldom can I transpose my impressions really so accurately in numbers that I can communicate them to you.’
I: ‘And I cannot play the piano like you. You saw that I can play only simple tones, not complicated sonatas; but you in your turn do not know any higher mathematics. If I had more of your skill and you more of mine, then you would always be able to communicate number patterns to me and I would be able to do calculations with them. These patterns or configurations – others say constellations, but I believe that the stars have nothing to do with them – reach down into the world of animals and plants, perhaps even deeper. They might be precisely what indicates “how warm it is” – to use your terminology – and feeling one’s way into their varying play would show lines of development.
This would certainly not take us back to the old idea that the world behaves like a clockwork that runs its fully predetermined course; and this for the very reason that our attempt to observe these configurations and their numbers is an intervention that must disturb nature. This would leave open different possible lines of development and would in general only indicate dispositions for what results, not certainties. One would always have to assume a certain freedom for what will happen, in particular with respect to the choice of the “key” in which a “melody” gets realized.
But if we could develop the ability to perceive these configurations of the moment and to handle them, then we would understand better how in nature the fluctuations of chance come and go in such a way that they bring about meaning or purpose. In that case the captain would say the right word at the right moment and so would the master – ‘
She: ‘And the girl you told me about could marry.’
I: ‘Then we would know more of the large country in the North of which we now can see the outline only and know more of its inhabitants. But today I have seen the homeland from afar. Does the homeland not inseparably belong to the master? Just as the master changes his shape in course of time, so there exists a past, a present and a future homeland, just as the feminine has a past, a present and a future face.’
After a pause I continued: ‘I’m sad. Because, just like so many others, I see the homeland from afar, but I will not enter it.’ And I played a minor chord with lots of black keys.
But the lady responded: ‘But that is also good.’ – and at this moment I clearly noticed her slit eyes again – ‘You forget the fourth, the timeless, both in the case of the homeland and in the case of the feminine. That alone is the unity in the conflict between the three which constitutes life itself.’
This instruction by the lady impressed me very much. Modestly I said to her: ‘This lesson has been going on already for a long time; I have to go back to my men’s world, among the people. But I will return.’
She: ‘What do you want to do among the people?’
I: ‘I will try to reconcile the master at all costs.’
The voice of the master answers immediately, more friendly than before: ‘That is what I have long waited for.’
I (to the lady): ‘Now that he has been reconciled I can give you your dignity as a woman back.’
She: (astonished): ‘What do you mean? Ah, I see, you allude to what I said earlier about being in bondage to the master.’
She only smiles.
I: ‘Goodbye for now. Whatever subject I will discuss in the men’s world – I shall owe thanks to the lady.’
Thereupon I made a deep bow and said to myself: ‘My consciousness cannot exist without a pair of opposites. That is why for me as a man the unity beyond my consciousness will always be with my lady.’
I now felt it was time to leave, but once more I heard the voice of the master: ‘Wait. Transformation of the centre of evolution.’
I thought: ‘In earlier times one said: lead turns into gold.’
At that moment the lady slipped a ring from her finger which I had not noticed before. She let it float in the air and taught me:
‘I suppose you know the ring from your school of mathematics. It is the ring i.’
I nodded and spoke the words:
‘The i makes the void and the unit into a couple. At the same time it is the operation of rotating a quarter of the whole ring.’
She: ‘It makes the instinctive or impulsive, the intellectual or rational, the spiritual or supernatural, of which you spoke, into the unified or monadic whole that the numbers without the i cannot represent.’
I: ‘The ring with the i is the unity beyond particle and wave, and at the same time the operation that generates either of these.’
She: ‘It is the atom, the indivisible, in Latin…’ When she spoke these words she gave me a significant look, but it seemed to me not necessary to say Cicero’s word for the atom aloud.
I: ‘It turns time into a static image.’
She: ‘It is the marriage and at the same time the realm of the middle, which you can never reach alone but only in pairs.’
There was a pause; we waited for something.
Then the voice of the master speaks, transformed, from the centre of the ring to the lady:
Now I knew I could go out of the room into normal time and normal everyday space.
When I was outside, I noticed I was wearing my coat and hat. From afar I heard a C-major chord of four notes C E G C, apparently played by the lady herself when she was on her own again.
We would like to thank the Pauli Committee at CERN for giving us the permission to publish an English translation of Die Klavierstunde.
The translation which we made of Die Klavierstunde is close to the original. If Pauli regards in German the musical interval G B-flat as a fourth, he does so in English, even though it is a third. Moreover, we have preserved Pauli’s switching from the past tense to the present and back. Apparently some parts of the Piano Lesson were so vivid to his consciousness during the time of writing that he used the present tense. His ‘Lecture to the strangers’ has been translated in such a way that it links up with the English edition of his writings on physics and philosophy:
Pauli, Wolfgang, Writings on Physics and Philosophy, edited by Charles P. Enz and Karl von Meyenn, Springer-Verlag, Berlin/Heidelberg, 1994.
The more literary parts of the Piano Lesson have been compared with the English edition of Pauli’s letters to C.G. Jung:
Meier, C.A. (Ed.), Atom and Archetype. The Pauli/Jung Letters, 1932-1958, with the assistance of C.P. Enz and M. Fierz, translated from the German by David Roscoe, with an introductory essay by Beverly Zabriskie, Princeton University Press, Princeton, New Jersey, 2001.
The original German text of the Piano Lesson was published for the first time in the proceedings of a conference about the irrational in the sciences held in Ascona (1993) and organized jointly by the C.G. Jung Institute in Küsnacht and the Federal Institute of Technology (ETH) in Zürich:
Pauli, Wolfgang, Die Klavierstunde. Eine aktive Phantasie über das Unbewusste, in: H. Atmanspacher, H. Primas, E. Wertenschlag-Birkhäuser (Eds.), Der Pauli-Jung Dialog und seine Bedeutung für die moderne Wissenschaft, Springer-Verlag, Berlin, 1995, pp. 317-330.
The active imagination constitutes also a part of the scientific correspondence of Pauli:
Meyenn, Karl von (Ed.), Wolfgang Pauli. Wissenschaftliche Briefwechsel, Band IV, Teil II: 1953-1954, Springer-Verlag, Berlin, 1999, pp. 330-340.
The first detailed interpretation of the Piano Lesson as a whole has been given in:
Erkelens, Herbert van, Wolfgang Pauli und der Geist der Materie, edited by Thomas Arzt, in collaboration with Eva Wertenschlag-Birkhäuser, Charles P. Enz and Bernward Thiel, Verlag Königshausen & Neumann, Würzburg, 2002.