To Robert L. Kroon 15 November 1958
Astrology is one of the intuitive methods like the I Ching, geomantics, and other divinatory procedures.
It is based upon the synchronicity principle, i.e., meaningful coincidence.
I have explored experimentally three intuitive methods: the method of the I Ching, geomantics, and astrology.
Astrology is a naively projected psychology in which the different attitudes and temperaments of man are represented as gods and identified with planets and zodiacal constellations.
While studying astrology I have applied it to concrete cases many times.
There are remarkable coincidences, e.g., the position of Mars in the zenith in the famous horoscope of Wilhelm II, the so-called "Friedenskaiser."
This position is said already in a medieval treatise to mean always a casus ab alto, a fall from the height.
The experiment is most suggestive to a versatile mind, unreliable in the hands of the unimaginative, and dangerous in the hands of a fool, as those intuitive methods always are.
If intelligently used the experiment is useful in cases where it is a matter of an opaque structure.
It often provides surprising insights.
The most definite limit of the experiment is lack of intelligence and literal-mindedness of the observer.
It is an intelligent apercu like the shape of the hand or the expression of the face-things of which a stupid and unimaginative mind can make nothing and from which a superstitious mind draws the wrong conclusions.
Astrological "truths" as statistical results are questionable or even unlikely.
(Cf. my paper "Synchronicity: An Acausal Connecting Principle" in Jung-Pauli: The Interpretation of Nature and the Psyche, Bollingen Series LI, New York 1952. Pag. 83 ff.)
The superstitious use (prediction of the future or statement of facts beyond psychological possibilities) is false.
Astrology differs very much from alchemy, as its historical literature consists merely of different methods of casting a horoscope and of interpretation, and not of philosophical texts as is the case in alchemy.
There is no psychological exposition of astrology yet, on account of the fact that the empirical foundation in the sense of a science has not yet been laid.
The reason for this is that astrology does not follow the principle of causality, but depends, like all intuitive methods, on acausality.
Undoubtedly astrology today is flourishing as never before in the past, but it is still most unsatisfactorily explored despite very frequent use.
It is an apt tool only when used intelligently.
It is not at all foolproof and when used by a rationalistic and narrow mind it is a definite nuisance. ~Carl Jung, Letters Vol. II, Pages 463-464