Wolfgang, you put in the mildly uncomfortable position of defending Jung, about whom I have no comprehensive knowledge, and in whom I have no compelling interest. But I do remember that he coined the term syncronicity to mean "apparently meaningful coincidence". Now, no rational person would argue that "apparently meaningful coincidence" doesn't exist, the operative word being "apparently".

I also recall with some confidence that Jung was unequivocal regarding his "belief" in astrology, tarot, etc. He was not a believer, rather he was interested in the image of human consciousness reflected in such belief systems.

I'd say that's a legitimate line of inquiry, and quite rational.