The History of Perceptual Positions
Today's NLP theory of Perceptual Positions was originally formulated by John Grinder and Judith DeLozier in 1987. It extended earlier concepts of referential index and Gregory Bateson's concepts of double and triple description. 3rd position was influenced by Milton Erickson's hypnotherapeutic concept of disassociation (as distinct from dissociation). Further developments and refinement of theory and applications were made by Robert Dilts and Todd Epstein in the early and mid 1990s.
The importance of Perceptual Positions in NLP, its practical uses, and the prevalence of the model have made it one of the most successfully used fundamentals in the pantheon of applied NLP.