To Werner Nowacki
Dear Professor Nowacki, 22 March 1957
I don't want to miss the chance of thanking you for your thoughtfulness in sending me your interesting article.
Your ideas go back, in modern form, to the familiar world of Plato's Timaeus, which was a sacrosanct authority for medieval science-and rightly so!
Our modern attempts at a unitary view, to which your article makes very important contributions, do indeed lead to the question of the cosmic demiurge and the psychic aspect of whole numbers.
From the fact that matter has a mainly quantitative aspect and at the same time a qualitative one, even though this appears to be secondary, you draw the weighty conclusion, which I heartily applaud, that, besides its obviously qualitative nature, the psyche has an as yet hidden quantitative aspect.
Matter and psyche are thus the terminal points of a polarity.
The still largely unexplored area between them forms the terra incognita of future research.
Here tremendous problems open out which you have approached from the physical side.
It seems to me that for the time being I have exhausted my psychological ammunition.
I have got stuck, on the one hand, in the a causality (or "synchronicity") of certain phenomena of unconscious provenance and, on the other hand, in the qualitative statements of numbers, for here I set foot on territories where I cannot advance without the help and understanding of the other disciplines.
In this respect your article is uncommonly valuable and stimulating.
I am particularly grateful to you for your appreciation of the transcendent "arranger."
C.G. Jung ~Carl Jung, Letters Vol. II, Pages 351-352.