Dear Professor Jung, [Zollikon Zurich) 24 November 1950

It was with great interest that I read the latest version of your work on “synchronicity.”

We had basically agreed in the past on the possibility and usefulness and also, in view of the Rhine experiments, on the necessity of a further principle of interpretation of nature other than the causal principle.

After the turn taken in your Ch. II, “The Astrological Argument: it seems that our points of view have come one step closer.

1. In several discussions last autumn and winter (which also gave me the opportunity to observe a great interest in your concept of synchronicity in
places where I would not have expected it), ( repeatedly expressed my hope that such a turn would come about.

For example, ( I said to M. Fierz and C. A. Meier at the time, “It is really paradoxical that physicists are now obliged to tell psychologists that they must not eliminate the unconscious in their statistical investigations!”

And now the unconscious has returned in the form of the “lively interest of the test persons or the psychic state of the astrologer”; here your statement about “the pernicious influence of the statistical method on the determination of synchronicity in terms of figures” (p. 35) seems to be the most important result of your investigations.

This “pernicious influence” consists in the elimination of actual influence of the psychic state of the of the participants by means of the statistical formation of mean values, in that these values are measured without this
psychic state being taken into consideration.

It actually seems to me a general and essential attribute of synchronistic phenomena, one that I would even like to incorporate into the definition of the term “synchronicity”; in other words, whenever an application of statistical methods, without consideration of the psychic state of the people involved in the experiment, does not show such a “pernicious influence,” then there is something very different from synchronicity going on.

I shall come back to this aspect later in connection with the discontinuities in microphysics.

The result you give of your investigation, according to which the continually renewed interest of your test persons is decisive, even makes astrology seem a secondary factor in this result and sets up favorable results for traditional astrology, in analogy to the “hits” in the Rhine experiment.

ust a quick question here: In the Rhine experiment, would it be possible to imagine test persons who produce a “negative” effect-i.e., who always come up with fewer hits than statistics would lead one to expect?

In your statistical experiment on the comparison between the horoscopes of married and single people, are there also test persons who, for example, find the sun-moon conjunctions predominantly with single people instead of married ones, precisely because their psychic state indicates a particular resistance to astrology?

When I say “predominantly,” I mean more frequently than the chance statistics would lead one to expect?

I am reasonably certain that the astrological case and Rhine’s ESP experiment will also behave analogously in this respect; but it might also be that the bringing in of the archetypes in both cases hinders the possibility of “negative” test persons.)

I have not examined the statistics in Tables I to V in detail, as this would take a lot of time and trouble, and anyway, unless I am mistaken, this whole material has been checked by Mr. M. Fierz, who has more experience in such matters. (Should I be wrong in assuming this, then I would strongly recommend you to call on him again.

His present address, probably until about the end of April 1951′, is: The Institute for Advanced Study, Princeton, N.J.)

At any rate, your result corresponds perfectly to my expectations.

A positive result, independent of the state of the astrologers, would contradict the well-known causality of the processes involved.

In truth, nature is so fashioned that-analogous to Bohr’s “Complementarity” in physics-any contradiction between causality and synchronicity can never be ascertained.

2. This now leads me to the question, the discussion of which forms the main part of this letter.

How do the facts that make up modern quantum physics relate to those other phenomena explained by you with the aid of the new principle of synchronicity?

First of all, what is certain is that both types of phenomenon go beyond the framework of “classical” determinism.

But this in itself does not answer the question, which is touched on in several places in Ch. I and IV of your work.

Naturally, this question is of particular interest to me as a physicist; I have been discussing it and thinking
about it at great length for a year.

What appears to me of fundamental importance is the requirement made of a law of nature in any experimental science–namely, that in principle at least it should relate to reproducible processes (also indicated by you
on p. 2).

In nuclear physics, it has turned out that the statistical character of these laws of nature is the price that has to be paid for fulfilling this requirement of reproducibility.

Now in physics, the essential aspect of uniqueness (for which there has never been a place in the physical laws of
nature) has manifested itself in an unexpected place.

This place is the observation itself, which is unique (or is an act of creation, if you will) because it is impossible to eliminate the influence of the observer by means of determinable corrections.

The type of statistical law that thus comes into being (one that is not reproducible by statements on individual cases), which acts as a mediator between the discontinuum of individual cases and the continuum that can only be realized (approximately) in a large-scale statistical framework, may be described as statistical correspondence.”‘

(The law of half-life periods in radioactive decay is a special case of this kind.)

At least the statistical regularities of the natural laws of microphysics are reproducible (independent of the psychic state of the observer), a case in point being the above-mentioned half-life periods.

There also seems to me here (cf. in this respect the criterion formulated above on the pernicious influence” of
statistical methods on synchronicity) such a fundamental difference between the acausal physical phenomena (such as radioactivity or any other discontinuity that comes under the “correspondence” of physics) and the
· synchronistic” phenomena in the narrowest sense of the term (such as ESP experiments of mantic methods) that I would like to propose that they be construed as phenomena or effects on different levels.

On these different levels there is a difference similar to that between a unique pair continuing series (although in the latter at least the statistical characteristics tics are reproducible).

Although in the second case, too, it is something that cannot be covered by the old deterministic form of natural law, I nevertheless, as a physicist, have the impression that the ‘statistical correspondence” of quantum physics, seen from the point of view of synchronicity, is a very weak generalization of the old causality.

This also manifests itself in the fact that although microphysics allows for an acausal form of observation, it actually has no use for the concept of “meaning.”

So I have grave misgivings about placing physical discontinuities and synchronicity on the same level, which is what you do on p. 58.

If you do not share my misgivings, I shall be most interested to hear what your arguments are.

To emphasize the difference between the case of microphysics and any cases involving the psyche, I proposed a quaternary schema in an unpublished essay on “background physics” written in 1941.

In the schema, the different pairs of opposites are intended to correspond to these two cases.

The pair of opposites for physics is:

Of course, I cannot claim that the whole quaternity that I proposed at that time is a genuinely suitable expression for “synchronicity.”

But a further characteristic of this schema, which seems important to me, is that space and time are not placed opposite each other, which a modem physicist would find particularly unacceptable.

I admit that this placing of three-dimensional space opposite one-dimensional time seems more natural in the physics of Newton (which can be said to have begun with Kepler) than in modem relativity and quantum physics, and I am also aware that time and space are psychologically different in that the existence of a memory (recollection) distinguishes the past from the future, for which there is no analogy in space.

Yet the positioning of space and time opposite each other in your schema on p. 59 does not really seem acceptable to me.

For a start, they do not form a true pair of opposites (since space and time can easily be applies simultaneously to the phenomena), and second the reasons you yourself give on p. 17a for the basic identity of space and time are very sound ones.

That is why I would now like to make the following compromise proposal for a quaternary schema as a basis for discussion; it avoids the opposing of time and space and perhaps combines the advantages of yur schema and the one I drew up in 1948.

On p. 61, where you talk about the “triadic world picture,” perhaps one could replace “by means of space, time, and causality” (8th line from the bottom) by “and the notion of causality.”

That would also fit in better with the term “three-principles doctrine,” since continuity (natura non facit saltus) can certainly be viewed as a characteristic principle for the (classical) scientific age.

3. When you use physical terms in order to explain psychological terms or findings, I often have the impression that with you they are dreamlike images of the imagination; this impression is usually accompanied by the feeling that the sentences you write here stop at the very point where they should begin.

For example, on p. 9 it says: “The physical analogy for this (for a coincidence in time) “is radioactivity or the electro-magnetic field: And on p. 10 it says of the archetypes that: “They represent a field of force that can be compared with radioactivity: Such sentences cannot be understood by any physicist, since he would never compare a field of force (neither electromagnetic nor any other) with radioactivity.

The concept of the physical field of force is based originally on the illustrative idea of a state of tension of the “ether” penetrating space.

This state was used as the medium of “ponderomotoric” effects between bodies (e.g., electrical and magnetic ones).

Field theory has made itself independent (since Faraday) in that a real existence was attributed to the state of tension even when it is not made visible with specimen bodies.

Later, the concrete-mechanistic image of the state of tension and the medium of ether was abandoned in favor of the abstract view that the relevant physical described in mathematical terms simply by appropriate continuous _
functions of the space and time coordinates, dispensing with descriptive images.

It was then the task of “field physics’ to establish the laws that fulfilled these functions, together with the specifications as to how these said functions, with the aid of test bodies, can-in theory at least-be measured. (I myself have a few ideas about the analogies of this physical field theory with the psychological notion of the unconscious and about the parallels in the temporal course of the development of these two concepts, but I do not want to prejudice your judgment.)

The essential thing about radioactivity is the transmutation of a chemical element that is connected with the emission of rays transporting energy (possibly of different sorts).

These rays are “active,” i.e., they produce chemical and physical action when they encounter matter.

Such analogies as
{
Synchronistic coincidence or of archetypes Field of force or Radioactivity can be of great interest, but only on condition that the tertium comparatiionis is given (and possibly what the differences are).

My personal wish is not that you delete the sentences mentioned but rather that you extend and elucidate them.

4. As you yourself say, your work stands and falls with the Rhine experiments.

I, too, am of the view that the empirical results of these experiments are very well founded.

Given the importance of the ESP experiments for your synchronicity principle, I would appreciate it if you would make a point of explaining how, in your view, the so-called PK (“Psychokinesis) experiments
that you mentioned on p. 8 are to be interpreted.

Does the person expressing the wish concerning the results of the dicing have a prefigured image of the way the dice will go?

You mention in this connection a psychic “relativity of mass,” but you do not go on to say what you mean by this nor how such an assumption can explain the PK experiments.

Here, too, I suspect that these are “dreamlike images of the imagination” of yours, and once again I would welcome further clarification.

There are other interesting details in your work that I would like to give more thought to (e.g., the connection between mantic methhods and the psychology of the number concept), but at the moment I have nothing new to report.

It’s about time I brought this long letter to a close.

I am hopeul that the questions that are still open to any differences still remaining in our points of view will be cleared up, given the basic agreement pointed out at the beginning of this letter.

With best wishes,

Yours,

W. Pauli ~Wolfgang Pauli, Atom and Archetype, Pages 53-59

Dear Professor Jung, Zollikon-Ziirich, 28 June 1949

Many thanks for your interesting manuscript and your friendly letter.

I should first of all like to point out that the Rhine series of experiments seem to me to be a totally different type of phenomenon from the other phenomena listed by you as “synchronistic.”

For with the former I cannot see any archetypal basis (or am I wrong there?).

This for me, however, is crucial to an understanding of the phenomena in question, as is your earlier observation (Eranos Jahrbuch 1947 [1946]) that their appearance is complementary to the archetypal contents becoming conscious.

I regret very much that this aspect is not mentioned at all in your latest work.

Perhaps you could make further additions here, for it would make it all easier to understand.

In this way, the appearance of the synchronistic phenomenon actually seems to be connected to a definite state of consciousness (this term is deliberately rather vague).

Your proposed statistical experiment on the horoscopes of married and single people should be carried out on a broader scale and under very strict conditions.

Whatever the outcome I do not discount a negative ne(, it will add further to our knowledge.

Speaking for myself, I can relate much better to those situations where an external event conincides with a dream than to what emerges from a series of statistics.

Whereas I have some personal experience with the former, my intuition lets me down when it comes to the latter.

I have now given much thought to yoru report about the coninciding of the scarab in the dream with the real insect and have attempted to feel myself into the situation.

I shall return to this below, where it is more relevant.

At this point I shall deal with the questions broached at the end of your letter about the relationship between psychology and physics.

This gives me an opportunity to extend last year’s essay on “background physics” by discussing the symbol “radioactivity; which at the time was no more than a key word.

This is also the best answer I can give to your question at the moment.

The idea of meaningful coincidence-i.e., simultaneous events not causally connected-was expressed very clearly by Schopenhauer [1785-1860j in his essay, “[Transzendente Spekulation] tiber die anscheinende Absicbtlichleit
im Schicksale des Einzelnen [On the Apparent Design in the Fate of the Individual].”

There he postulates an “ultimate union of necessity and chance: which appears to us as a “force: “which links together all things, even those that are causally unconnected, and does it in such a way that they come together just at the right moment.”

He compares causal chains with the meridians, simultaneousness with parallel circles corresponding exactly
to your “equivalent cross-connections.”

He sees, “albeit imperfectly from a distance” the compatibility of the opposition “between the apparent
chance element in all occurrences in the life of the individual and their moral necessity in the shaping of that life in accordance with a transcendental practicality for the individual-or, in popular language, between the
course of nature and providence.”

Perhaps some reference in your work to this essay of Schopenhauer’s would be a good idea, all the more so as he, too, was influenced by the ideas of Eastern Asia that you quote so frequently.

Although Sch.’s essay is probably known to only a relatively small number of physicist, it is always pleasing in a fundamental issue to be able to make connections with what is already in existence.

This essay of Schopenhauer’s had a lasting and fascinating effect on me and seemed to be pointing the way to a new trend in natural science.

But whereas Sch. wanted at all costs to cling to rigid determinism along the lines of the classical physics of his day, we have now acknowledged that in the nuclear world, physical events cannot be followed in causal chains through time and space.

Thus, the readiness to adopt the idea on which your work is based, that of the “meaning as an ordering factor” is probably considerably greater among physicists that it was in Schopenhauer’s day.

Accordingly, I myself have no serious misgivings about such an idea.

It does seem to me, however, that in your interpretation the term “acausal” needs to be made more precise, and the special use of the concept of time needs further elaboration.

For the physicist, the words “causal” and “causality” have a much less specific meaning than the word “determinism.”

And what is more, the word “acausal” means different things to different writers.

According to your interpretation of the “synchronistic” phenomenon (I refer particularly to pp. 20 and 21 of your essay), it occurs through duplication or multiplication of an abstract ordering factor, the external manifestation of which is in fact doubled or multiple.

In this sense, the ordering factor could also be described as the cause of the synchronistic phenomenon.

This cause, however, could not be conceived of in time and space.

Conversely, if only objects in lime and space can be described as causal, then synchronistic phenomena do in fact appear to be “acausal.”

Just as in microphysics, the characteristic feature of the situation is the impossibility of simultaneously
applying the principle of causality and the classification of the phenomena in time and space.

What is much more difficult for me than the question of the definition of “acausal” is the entrance of the concept of time into the word “synchronistic.”

Initially it refers expressly to phenomena that are supposed to be simultaneous in definitions in the usual physical sense.

Later, however (top 01 p. 21), you try to include phenomena such as predicting the future, which do not occur at the same time.

The word “synchron” thus seems to me somewhat illogical, unless you wish to relate it to a chronos that is essentially different from normal time.

This seems to me to be a difficulty that is not just one of formal logic but also a factual one.

For it is by no means easy to see why events that “express the presence of one and the same image or meaning” have to be simultaneous: The them time presents me with greater difficulties than the term meaning.

So what is the connection, the, between meaning and time?

By way of experiment, I shall construe your interpretation as follows: First of all, events in meaning can be perceived more easily when they are simultaneous.

But second, simultaneity is also the characteristic that determined the unity of conscious contents.

So inasmuch as “synchronistic” events form what you have termed a “psychoid” initial stage of consciousness, it is understandable if (not always, but in many cases) they also share this standard of characteristic of simultaneity.

This also suggests that the meaning-connection, a primary agent, produces times as the secondary one.

(I hope these vague formulations will become dearer in the course of our conversations.)

What seems satisfactory to me is that the ordering factor, “consisting of meaning.” which contains time (the chronos) as a special case, as the masculine principle, stands in contrast to the feminine-indestructible one (causality in the narrowest sense, energy, collective psyche), as also seems to be the case in microphysics.

I now come to your questions concerning the possibility of linking together some of the physical facts mentioned by you with the synchronicity hypothesis.

The question is a very difficult one, as it seems to be connected with some of my personal experiences in “background physics” which mainly manifest themselves in dreams.

The energy quantum and the half-life radium decay seem to me much better suited to illustrate these connections
than the two other phenomena quoted by you, since they have an elemental and fundamental character.

Perhaps we can discuss this energy quantum again when we meet; at this point I would like to pick up on the physical phenomenon of radioactivity.

To make my views and my attitude to this question clearer, permit me to conduct a fictive thought experiment with you.

Please imagine that on the evening after the incident with the scarab that you have described, a stranger visits you and says something on the lines of: “Congratulations, doctor, on having finally succeeded in producing a radioactive substance. It will be most beneficial to the health of your patient.”

Your assertion that there are no radioactive substances in your house and that the atmosphere is also free of radioactivity falls on deaf ears.

In fact, the stranger proceeds to explain in detail the half-life of the substance and the residual activity.

I have been playing this type of game for about 5 years now; it is played according to strictly defined rules and is so methodical that it cannot simply be dismissed as madness.

My initial attempts to throw the stranger out were soon abandoned, for although he is friendly by nature, the visitor can soon turn very unpleasant.

Judging from your question about radioactivity, I automatically assume that you are conspiring with the stranger.
expect me to agree with this conclusion.

As to what the stranger means, I can only deduce this indirectly from his reactions to my intellectual hypotheses; I am never completely sure about them.

Nor did he come to me on such easily perceived occasions as those I have created for my thought experiment with his remarks on radioactivity.

And before I could get down to finding out anything about “radioactivity” as he understood it, I had to have a rationally acceptable idea about who the stranger was.

The hypotheses that at the moment I just use for myself are the following:

1. “The stranger” is the archetypal background constellated by the system of scientific concepts of our time.

2. The expressions that emerge spontaneously from this background, such as “a radioactive substance has been produced” or “there is radioactivity; can be translated into the language of reason as follows: “a state of consciousness has been produced, or is simply present, which is accompanied by the multiple manifestation of the ordering factor in meaningfully related (usually simultaneous) events.”

The language of the background is in the first instance a language of parable.

It seems to demand that reason, by dint of dedicated work, should translate it into a neutral language that adequately fulfills its requirements with regard to the distinction between “physical” and “psychic.”

This neutral language does not yet exist, but one can attempt to make progress in the direction of its construction by means of careful analysis of analogies, such as the differences in what is indicated by the same words in the parable language.

With regard to the example in question-that of “radioactivity” –what strikes me first from the psychological angle is that a far-reaching parallel exists with what the alchemists referred to as the “production of the red
tincture.”

Experience has shown me that what you call a “conjunction process” is generally conducive to the appearance of the “synchronistic” phenomenon(referred to as “radioactivity” by the “stranger”).

And it is more likely to make its appearance when the pairs of opposites keep in balance a much as possible.

In the I Ching this moment is depicted by the sign “Chen” (shock, thunder) (Wilhelm Baynes, hexagram 51).

In the case of your scarab, I am fairly sure that it was one of those moments, since you say that it was preceded by a long, drawn-out course of treatment.

From all the material you have at your disposal, it must be easy to establish the conjunction process
and its situation when the synchronistic event occurred.

In this respect, I would be very interested to know in which month of the year it happened.

The equinoctial days are particularly suitable.

I would be prepared to bet 4:1 that it was in September or March and perhaps 1:1 that it was in the second
Half of the month.

(Perhaps those who believe in horoscopes will hit on the idea of setting up horoscopes for the moment when such events occur.

For according to your report, a spiritual birth has taken place, and there can be no essential difference between that and a physical birth.)

I regard it as evidence of progress in our knowledge when, in this connection, the alchemistic concept of the “red tincture” is replaced by the “radioactive substance.”

Between the phenomena compared there are the following illuminating analogies:

1. Just as in physics, a radioactive substance (through “active precipitation” from developing gas-like substances) radioactivity” contaminates” a whole laboratory, si the synchronistic phenomenon seems to have the tendency
to spread into the consciousness of several people.
3. The physical phenomenon of radioactivity consists in the transition of the atomic nucleus of the active substance from an unstable early state to its stable final state (in one or several steps), in the course of which the radioactivity finally stops, Similarly, the synchronistic phenomenon, on an archetypal foundation, accompanies the transition from an unstable state of consciousness into a new stable position, in balance with the unconscious, a position in which the synchronistic borderline phenomenon has vanished again.

3. Once again, the difficult thing here for me is the time concept. In physical terms, it is known that the actual amount of a radioactive substance (which can be measured by weighing it) can be used as a clock, or rather its
logarithm can: In a definite time interval (selected as sufficiently small), it is always the same fraction of the existing atoms that disintegrates, and two time intervals can conversely be defined as the same when the same fraction of the initially existing atoms disintegrate in them. But this is where the statistical character of the laws of nature comes into play:

There are always irregular fluctuations about this average result, and they are only relatively small when the selection of the existing active atoms is sufficiently large; the radioactive clock is a typical collective phenomenon.

A quantity of radioactive substance consisting of just a few atoms let’s say 10) cannot be used as a clock,

The moments in time when the individual atoms disintegrate are in no way determined by the law. of nature, and in the modem view they actually do not exist independently of their being observed in appropriate experiments,

The observation (in this case: the energy level) of the individual atom releases it from the situation· (i.e., meaning.) connection with the other atom and links it instead (in meaning) with the observer and his time.

This leads to the following analogy with the synchronistic phenomenon on an archetypal basis: The case where it has not been determined whether the individual atom of a radioactive clock is in the initial or final stage of radioactive decay corresponds to the connection of the individual with the collective unconscious through an archetypal content of which he is unconscious.

The ascertaining of the state of consciousness of the individual, which emerges from this collective unconscious and which causes synchronistic phenomenon to vanish, corresponds to the determination of the energy level of the individual atom by means of a special experiment.

This is as far as I have got.

I very much look forward to talking over these questions with you, as well as other examples, and not just radioactivity.

I have spoken to C. A. Meier, and we have agreed that Thursday, 14luly, would be a good day for us both to visit you in Bollingen.

He will be in touch with you to see whether this day is convenient for you.

Please excuse my lack of brevity.

With best wishes,

Yours sincerely, W PAULI ~Wolfgang Pauli, Atom and Archetype, Pages 36-42