Dear Professor Jung, Zollikon-Zurich, 12 December 1950

I was very pleased to receive your long letter, not just because it made a lot of things clear but also because it provided me with more food for thought.

Re 2. In my last letter, I suggested that synchronicity should be defined in a narrower sense so as to comprise effects that only appear when there is a small number of individual cases but disappear when there is a larger number; you, however, have now done the opposite by means of a definition of synchronicity which, in a broader sense, comprises every acausal and-I should like to add-holistic system.

You do this so that the non-psychic among these systems-namely, the compiled facts of “statistical correspondence” in quantum physics-also come under the same general category.

What has so far prevented me from adopting the broader term is the fear that with the more generally defined term too much might get lost that is specific to psychic and half-psychic synchronicity.

In quantum physics, there are not just effects that appear with large numbers instead of with small ones, and not only is the term “meaning” not the right one here (which you have written about at great length) but also the concept of the (psychic or psychoid) archetype cannot be used so lightly in the acausalities of microphysics.

So if one wishes to use the more extensive definition of synchronicity, then one must deal with the question of which is the more general case that includes as a special case that of the archetype as ordering factor.

In quantum physics, the observer makes a conscious choice (which always implies a sacrifice) between mutually exclusive experimental setups.

Nature replies to this man-made setup in such a way that the result in the individual case cannot be predicted and cannot be influenced by observer; but when this type of experiment is conducted on several occasions there is a reproducible static regularity, which is in itself a holistic orderedness of nature.

The experimental setup forms a whole that cannot be divided up into parts without fundamentally changing and affecting the results so that in nuclear physics the definition of the term “phenomenon” which must also include the particulars of the whole experimental setup in which it occurs.

Thus, the more general question seems to me the one about the different types of holistic, acausal forms of orderedness in nature and the conditions surrounding their occurrence.

This can either be spontaneous or “induced” -i.e., the result of an experiment devised and conducted by human beings.

The latter is also what happens with mantic methods, but the result of the experiment cannot be predicted here (e.g., the throwing of a coin when consulting the oracle); it is just assumed that there is a “connection through equivalence” (meaning) between the result of the physical process and the psychic state of the person conducting the experiment.

In cases of non-psychic acausality, on the other hand, the statistical result as such is reproducible, which is why one can speak here of a “law of probability” instead of an “ordering factor” (archetype).

Just as the mantic methods point to the archetypal element in the concept of number, the archetypal element in quantum physics is to be found in the (mathematical) concept of probability-i.e., in the actual correspondence between the expected result, worked out with the aid of this concept, and the empirically measured frequencies.

In connection with this, it should be noted that the specialized field “Fundamentals of Mathematics” is in a state of great confusion at the moment as a result of a large-scale undertaking to deal with these question, an endeavor that failed because it was one-sided and divorced from nature.

In this field of research into the fundamentals of mathematics, the “basis of mathematical probability calculus” marks a particular low point.

After reading an article on this subject in a journal, I was dismayed at the difference, of opinion, and later I heard that, whenever possible, experts avoid discussing this subject on the grounds that they now they will not be able to agree!

A psychological approach would be both appropriate and very useful here.

It seems to me absolutely essential that when you talk about physical discontinuities in chap. IV, you should indicate clearly the distinctions of terminology between the non-psychic acausal ordering systems on the one hand and the half-psychic and psychic synchronicities on the other.

In your letter, you actually promised that you would do this.

Bearing this in mind, I have once again carefully weighed up the pros and cons of the narrower and broader definitions of ‘synchronicity.”

Pure logic gives us a free hand to choose either definition.

In such a cae, the deciding factor is intuition, pointing the way to the future as it does, but his is psychology and the branch of psychology that I am particularly interested in-namely the scientific formation of concepts.

With me, the intuitive function has such a strong tendency toward the apprehension of holistic structures that despite all arguments to the contrary, I find myself leaning toward your broader definition: Given the impossibility of a direct application of the term “archetype” in microphysics, I am more inclined to believe that the present term “archetype” is inadequate rather than that your broader definition is in itself inappropriate.

For since your essay in Eranos Jahrbuch for 1946 [see Letter 37, n.1.], it seems to me that the term “archetype” is going through a phase of great change at the moment, and my intuition leads me to suspect that more changes are in the offing.

What is of consequence here is that several other important changes can be applied in both psychology and physics without that having been specifically so intended: similarity. acausality. ordering. Correspondence, pairs of opposites, and wholeness.

If the decision is now made to adopt the broader interpretation of the counter-principle to causality, then I have no doubt that your new formula of the “world picture quaternio” (p, 4 of your letter [46, par, 5]), which corresponds to my earlier wishes anyway, is exactly the proper expression.

If you extended chap, IV along these lines, it would be very different and in some respects more than simply a “resume”; it would be a glimpse into the future of natural philosophy.

Re 3. I was a little surprised at the note of resignation in your letter in the way you commented on your sentences referring to radioactivity and field, for there seems to be no objective reason for such resignation.

But in my explanation of my own point of view, I myself must also become psychological, otherwise I shall fail to deal with all the essentials; I am happy to swap roles and expose myself to the full brunt of your criticism.

As regards the “dreamlikeness” of your physical concepts, or your ideas in general, it seems to me that they are only accurate to a certain degree, when you say in your letter that they are based on the absence of abstract-mathematical character and on their “concreteness.”

I know a lot of people (such as chemists and radiologists) who approach physics from the experimental angle, and they all assure me that they have to imagine the physical conceptions “graphically,” since the mathematical-formula apparatus is not accessible to them.

With none of them would I speak of the “dreamlikeness” of their concepts but would rather call their images “concretist.”

The “graphicness” of your physical concepts is much more along the lines of an introverted view, which, as part of the picture, involves psychic ground” processes in the subject, which are to be found alongside the conscious use of physical concepts.

It is this, in my opinion, that defines the dreamlike nature of your concepts, which brings out analogies and

These “background” processes are not usually perceived, but I believe that they are always present in the unconscious.

I myself know them very well from physical” dreams, and that is why I feel that your “physical” concepts are not only interesting but also accessible to meaningful and rational interpretation if they are simply treated as dream symbols.

This is where I want to bring in my idea of a neutral language (which you were kind enough to quote), this language being interpretable both psychologically and physically, so as thus to obtain the “psychological correspondence” of the physical concepts.

In the case of field and radioactivity, which [as I remarked in my last letter] are not compared with each other by physicists in general, you seem to have particular problems, owing to the fact that a difference in the physical concepts stands in contrast to a similarity in their psychological correspondence.

But I believe this problem is not a serious one and is based on the fact that a crucial element is missing in your statements in the letter on the subject of the psychological correspondence to radioactivity.

In actual fact, the psychological correspondences to field and radioactivity also seem to differ from each other.

Expressed in the neutral language, what the two have in common is the idea of a conveyance of connections between spatial [and maybe temporal], distantly visible manifestations by means of an invisible reality.

Here both visible and invisible are to be understood in the sense of everyday life.

Both electromagnetic fields and the rays emitted by radioactive substances are invisible; it is only their mechanical or chemical effects on material bodies that are visible.

In finding the psychological interpretation of the neutrally formulated idea, one must take into account the fact that illustrative concepts are always based on causal interpretation, even when acausal connections are meant.

Invisible reality can thus be the collective unconscious, visible manifestations can also be conscious concepts [they are “visible” to the subject conceiving], and the causal connection “conveyed” can be a synchronistic one.

As we now move on to the concept of radioactivity, we are struck forcibly by the process of chemical transmutation of the radioactive nucleus as the feature that distinguishes radioactivity from the {static} field theory.

The nucleus is the center of the atom; the radioactive rays generally produce new radioactive centers where they encounter matter.

So let us test the following expression for “radioactivity” in the neutral language: A process of transmutation of an active center, ultimately leading to a stable state, is accompanied by self-duplicating {“multiplying”} and expanding phenomena, associated with further transmutations that are brought about through an invisible reality.

And now one does not have to look far for the psychological interpretation of this neutral expression.

The ‘active nucleus,” familiar to me as a dream symbol, has a close relationship to the lapis of the alchemists, and thus in your terminology is a symbol of the “Self.”

The transformation process as a psychic process is still the same today as that represented in the alchemical opus and consists of the transition of the “Self” into a more conscious state.

This process (at certain stages at least) is accompanied by the “multiplication” – i.e., by multiple outward manifestation of an archetype (this being the “invisible reality”), which again is the same as the “breaking of barriers through contingency” or “transgressivity” of the archetype type that you talk about in your letter.
The transformation process is the missing item in your letter when you talk of the psychological correspondence to radioactivity.

The psychic process is the same as with the alchemists, but in the physical process of radioactivity not only has the transmutation of the chemical element become reality, but acausality has now appeared on the scene in our conscious scientific ideas.

This symbolism, in contrast to that of the alchemists, seems to be more differentiated and more highly developed.

Whether or not you delete or elucidate the sentences on pages 9 and 10 of your work is a purely technical question; an explanation might become too long-winded.·

Re 4. What you say about the “relativity of mass’ and the PK experiments still seems to me very obscure, but perhaps that is all we can say about it at the moment, given the current level of our knowledge.

With the prefigured image of the test person, I actually did not mean a conscious conception but an unconscious prefigured image, operating from the unconscious.

As to your “quick” question about the positive result of the Rhine experiments when large numbers of dice are involved, I cannot come up with an answer.

I am very happy about this correspondence, for I now have the feeling that there is a real exchange of views on both sides about all these borderline problems.

Enclosed please find McConnell’s work.

Please let me know when you need your manuscript back.

With kind regards,

Yours sincerely, W P. ~Wolfgang Pauli, Atom and Archetype, Pages 63-67

Dear Professor, 23 January 1951

I am particularly indebted to you for having given me new heart.

When I enter the sphere of physical or mathematical thinking sensu strictiori, I lose all understanding of what the term synchronicity means; I feel as though I am groping my way through dense fog.

This feeling is obviously due to the fact that I do not understand the mathematical or physical implications of the word, which you certainly do.

I could imagine that, for similar reasons, the psychological aspect seems unclear to you.

As regards the narrower and broader meaning of the term synchronicity, which you have explained so clearly, it seems to me as “synchronicity” in the narrower sense is characterized not just by the aspect of the archetypal situation but also by acausality.

The archetype certainly characterizes the psychic and half-psychic: “Synchronicity” cases, but I wonder whether the “anomaly” of the so-called causal law-namely, acausality-is not a more general characteristic and “super ordinated” condition than the archetypal basis that can be traced in psychic and half-psychic “Synchronicity” cases.

The latter can only be ascertained as present through introspection but remains hidden to the outsider as long as I do not inform him of my observation.

If I keep my observations to myself, the former can only ascertain an acausal “so-ness” [“So-sein”]. especially in those cases where the archetypal tertium comparationis is not obvious (as in the case of the scarab, for example).

Like the time when I was working on the psychology of “Das Wandlungssymbol in der Messe [Transformation Symbol in the Mass) ,” approaching it from the angle of alchemy, it happened that a serpent tried to swallow a fish that was too large for it and consequently choked.

Fish is the other Eucharistic food, and in this case it is seized not by the person but by the chthonic spirit, the mercurial serpent.

(Fish = Christ. Serpent = Christ and the feminine darkness principle.)

At the time, I was the observer on the outside whho could only see the coincidence but not the common archytypal basis; i.e., I did not understand how the serpent corresponded to the Mass.

But I did feel very strongly that the case was one of meaningful coincidence-i.e., not just an irrelevant “so-ness” situation.

In this case, the only distinguishing feature is the presence of acausality, and in such situations and similar ones it is precisely this that has given me the idea of acausality is the more general definition, whereas the archetype is a characteristic that can be perceived occasionally where, almost by chance, an insight is possible.

Now if there are “nontransparent” cases of synchronicity even in the psychic sphere, then they are even likelier in the half-psychic or physical sphere.

In other words, what should emerge is that the general case is the acausal “so-ness” one, whereas “Synchronicity” is the causus particularis of a transparent “so-ness” situation.

But I can tum the argument around and say: Introspection teaches me that the archetype is characteristic of “Synchronicity” i.e., I is that special case of acausality in which the archetype can be perceived as the (transcendental) basis.

This perception is possible because the acausal case occurs (by chance) in the psychic sphere, where something can be perceived from inside through introspection; in the half-psychic, this is less possible and not at all in the
physical one.

With the merely psychoid (transcendental) nature of the archetype, its purely physical occurrence is by no means precluded.

It can thus be both the basis of the purely psychic and half-psychic synchronicity as well as physical acausality in general.

The old precept of the croatio continua and the correspondentia was applied to nature as a whole and Dot just
the psyche.

I fully agree with you that the synchronicity of the psychic sphere must be conceptually separated from the discontinuities of microphysics.

But this leaves open the question of whether one should subsume the facts of psychic “Synchronicity” i.e., the archetypal characteristic-to a general causality or subsume the latter to the universal validity of the archetype.

In the latter case, this would give rise to a Platonic world-picture with a mundus archetypus as its model: In the former, the I would appear with its archetypal characteristic as a psychic “anomaly” of general causality, just as acausality would need to be its physical anomaly.

Your idea that the probability concept in mathematics corresponds to the archetype was most illuminating.

In fact, the archetype represents nothing else but the probability of psychic events.

To a certain extent, it is the symbolically anticipated result of a psychic statistic.

This can probably be best seen in the tendency of the archetype to keep producing and confirming itself (cf. the reinstatement of a Goddess in Christian Olympus).

I am, of course, very pleased that you have indicated your inclination to consider seriously the extension of the “Synchronicity” theory.

Under these circumstances, you are fully justified in demanding a new interpretation of the term archetype.

It seems to me that the way to achieve this is via the analogy archetype-probability.

In physical terms, probability corresponds to the so-called law of nature; psychically, it corresponds to the archetype.

Law and archetype are both modi and abstract ideal cases that occur only in modified form in empirical reality.

My definition of the archetype as “pattern of behavior” accords with this interpretation.

But whereas in the sciences the law appears exclusively as abstraction derived from experience, in psychology
we encounter an a priori existing image, already complete as far as can be judged; this image occurs spontaneously, in dreams, for example, and possesses an autonomous numinosity, as if Someone had stated in advance with great authority: “What is coming now is of great significance.”

This strikes me as being in sharp contrast to the a posteriori character of the law of nature.

If that were not so, one would have to assume that the image-for example, of radioactivity-had always been present and that the real discovery of radioactivity (in this case) would simply be this particular image becoming

The way you deal with the image of the lapis raises the question for me of whether ultimately the symbols accompanying the lapis, such as the multiplicatio, do not indicate a transcendental basis common to both the physical and the psychic.

So although everything seems to indicate that radioactivity and its laws are something perceived a posteriori, it is nevertheless fundamentally impossible to prove that the law of nature is actually based on something toto coelo different from what we in psychology call archetype.

For in the end the law of nature, irrespective of its obviously empirical derivation, is always a psychic form as well, and nolens volens also has its origins in psychic premises.

Under these conditions, the analogy between the archetype and the constellation effects it radiates on the one hand, and the way the active nucleus affects its surroundings on the other, mean rather more than a simple metaphor, and the psychic transformation process would be, as you point out, the actual correspondence to radioactivity.

I shall now set about extending my manuscript along the lines of what we have agreed on and hope that I succeed in expressing myself clearly.

I shall close by once again expressing my thanks for the friendly and helpful interest you have shown,

With best wishes,

Yours sincerely, C.G.

~Carl Jung, Atom and Archetype, Pages 68-70