The American researcher Joseph Banks Rhine (1895 - 1980) and the Swiss psychiatrist Carl Gustav Jung (1875 - 1961) were contemporaries, the mutual interest in research led the two authors to establish an exchange of letters from 1934, which would last the next two decades. From this dialogue, important theoretical repercussions occurred in the work of the two authors, especially in relation to Jung. In our methodology we analyze the works of Rhine and Jung, with emphasis on the impact of experiments on extrasensory perception (ESP) on Jung's 1952 work, Synchronicity: A Principle of Acausal Connections. Despite existing controversies about Jung's concept, with some authors establishing that ESP and synchronicity are distinct events, the Swiss author clearly establishes three categories or aspects of his concept, two of which include ESP.
