Tactile hallucinations: conceptual and historical aspects.

A brief historical analysis of the general concept of hallucination is presented and the suggestion is made that it emerged as the unwarranted generalisation of a perceptual model that was meant to apply only to vision and the "distance senses". Against this background the evolution of tactile hallucinations is considered and its interaction with 19th century psychological theory explored. It is concluded that tactile hallucinations are sui generis phenomena which do not fit the conventional model and whose clinical identification rests on criteria so far unclear. A brief review of their taxonomy and diagnostic usefulness is presented. Some wider implications are drawn which should be relevant to the general concept of hallucination.