HOPPE'S DEFINITION OF HALLUCINATIONS

   In 1871 the Swiss physiologist Johann Ignaz Hoppe (1811-1891) defined hallucinations as follows: "Visions and hallucinations are... not false interpretations of something on hand, but mere constructionsofsomething-not-on-handfrom, and out of, something on hand (either out of something palpably on hand, or out ofsomething subjectively on hand, due to nervous excitation)."

   References

   Hoppe, J. (1871). Hallucinationen und Illusionen. Begriffserklärung und Wesen. Ein Beitrag zur Erkenntnisstheorie. Auf Grund von Untersuchungen. Basel: H. Amberger.