EMMINGHAUS'S DEFINITION OF HALLUCINATIONS
In 1878 the German psychiatrist Hermann Emminghaus (1845-1904) defined hallucinations as follows. "Hallucinationsare understood as phantasms that do not result from external impressions."
References
Emminghaus, H. (1878).Allgemeine Psychopathologie, zur Einführung in das Studium der Geistesstörungen. Leipzig: F.C.W. Vogel.