To F. Fischer
Dear Herr Fischer, 23 March 1958
In reply to your letter of March 18th I can only tell you that though Prof. Pauli has informed me of his collaboration with Heisenberg he did not-for understandable reasons-give me the details of this collaboration.
Unfortunately I am unable to express an opinion on Heisenberg's formula because, firstly, as said, I don't know the details, and secondly, I would not be in a position to follow the mathematical argument.
I deduce the fact that acausal phenomena must exist from the purely statistical nature of causality, since statistics are only possible anyway if there are also exceptions.
This relationship of the expected to the unexpected can be considered compensatory on heuristic grounds.
It is not improbable that a unitary formula would recognizably include the quaternity principle, but because of my ignorance of the actual state of affairs I would not venture any statements on this subject.
On the other hand, it is obvious to me that synchronicity is the indispensable counterpart to causality and to that extent could be considered compensatory.
By far the greatest number of polarities that occur in nature are compensatory in this sense.
This "world model" would indeed mean an incalculable upheaval in our understanding of the cosmos.
The upheaval has begun in any case with the posing of this question, Even though it cannot yet be answered with certainty.
C.G. Jung ~Carl Jung, Letters Vol. II, Pages 425-426