To Pascual Jordan
Dear Professor Jordan, 10 November 1934
Thank you very much for kindly sending me your offprints,! Some of which I already knew.
Although I am no mathematician, I am interested in the advances of modern physics, which is coming ever closer to the nature of the psyche, as I have seen for a long time.
I have often talked about it with Pauli.
One is, to be sure, concerned here with aspects of the psyche which can be mentioned only with the greatest caution, as one is exposed to too many misunderstandings.
Probably you will get a taste of them in time.
So long as you keep to the physical side of the world, you can say pretty well anything that is more or less provable without incurring the prejudice of being unscientific, but if
you touch on the psychological problem the little man, who also goes in for science, gets mad.
With respect to your paper I can only tell you that I have read it with the greatest interest.
It marks an extremely memorable moment in the history of the mind, the moment when the circle closes, or when the cutting of the tunnel from opposite sides of the mountain
I don’t know whether Pauli has told you of the letter I wrote him after reading your MS.
If not, I am taking the liberty of sending you a carbon copy.
At the same time I would like to tell you that I have asked my bookseller to send you the book containing my essay “The Structure of the Psyche.”
As to the hypothesis of the collective unconscious, not nearly all the material bearing on this matter has yet been published.
For the reasons mentioned above, I must restrict myself at present wholly to the parallelism of psychic phenomena.
With this in mind, I have also brought out a little book with the late Richard Wilhelm, which deals with a Taoist text called The Secret of the Golden Flower.
There you will find those parallels of which I speak.
The strange cases of parallelism in time, which are commonly called coincidences but which I call synchronistic phenomena, are very frequent in the
observation of the unconscious.
In this connection there is a rather crazy book by Kammerer, The Law of Series, which may be known to you.
It may be said in passing that Chinese science is based on the principle of synchronicity, or parallelism in time, which is naturally regarded by us as superstition.
The standard work on this subject is the I Ching, of which Richard Wilhelm brought out a translation with an excellent commentary.
Again with best thanks and kindest regards,
C.G. Jung ~Carl Jung, Letters Vol. 1, Pages 276-278