Dream telepathy is the purported ability to communicate telepathically with another person while one is dreaming. The first person in modern times to document telepathic dreaming was Sigmund Freud. Mainstream scientific consensus rejects dream telepathy as a real phenomenon, while alternative researchers and various spiritual traditions argue for its regular occurrence across cultures. Parapsychological experiments into dream telepathy have not produced replicable results. In the 1940s, it was the subject of the Eisenbud-Pederson-Krag-Fodor-Ellis controversy, named after the preeminent psychoanalysts of the time who were involved: Jule Eisenbud, Geraldine Pederson-Krag, Nandor Fodor, and Albert Ellis. History The notion and speculation of communication via dreaming was first mooted in psychoanalysis by Sigmund Freud in 1921. He produced a model to express his ideas about telepathic dreaming. His 1922 paper Dreams and Telepathy is reproduced in the book Psychoanalysis and the Occult (1953) and was intended to be a lecture to the Vienna Psycho-Analytical Society, although he never delivered it. Freud considered that a connection between telepathy and dreams could be neither proven nor disproven. He was distinctly suspicious of the whole idea, noting that he himself had never had a telepathic dream. (His two dreams that were potentially telepathic, where he dreamed of the deaths of a son and of a sister-in-law, which did not occur, he labeled as "purely subjective anticipations".) His ideas were not widely accepted at the time, but he continued to publicly express his interest and findings about telepathic dreaming. He also observed that he had not encountered any evidence of dream telepathy in his patients. Freud claims neutrality about the phenomenon itself, states that the sleep milieu has special likely properties for it if it does exist, and discounts all of the cases presented to him on standard psychoanalytic grounds (e.g. neurosis, transference, etc.). In the 1940s, Jule Eisenbud, Geraldine Pederson-Krag and Nandor Fodor described alleged cases of dream telepathy. Albert Ellis regarded their conclusions to have been based upon flimsy evidence, and thought that they could be better explained by bias, coincidence and unconscious cues than by dream telepathy. He also accused them of an emotional involvement in the notion, resulting in their observations and judgement being clouded. Psychologist L. Börje Löfgren also criticised dream telepathy experiments of Eisenbud. He stated that coincidence was a more likely explanation and the "assumption of paranormal forces to explain them is unnecessary." Experiments There have been many experiments done