Since the 20th century, the work in some subfields of physics research has been divided between theorists and experimentalists. Those theorists who lack an aptitude or interest in experimental work have on occasion earned a reputation for accidentally breaking experimental equipment. Pauli was exceptional in this regard: it was postulated that he was such a good theorist that any experiments would be compromised by virtue of his presence in the vicinity. For fear of the Pauli effect, experimental physicist Otto Stern banned Pauli from his laboratory located in Hamburg despite their friendship. Pauli was convinced that the effect named after him was real. He corresponded with Carl Jung and Marie-Louise von Franz about the concept of synchronicity and did so as well with Hans Bender, lecturer at Freiburg university Institut für Grenzgebiete der Psychologie und Psychohygiene, the only parapsychology chair in Germany.