The view, first proposed by H. A. Gleason in 1917, that vegetation is continuously variable in response to a continuously varying environment. Thus, no two vegetation communities are identical. It implies also that vegetation cannot be classified, and that recognition of particular individual communities will be difficult (the problem arising because of the difficulty of defining boundaries). This viewpoint underlies one of the two polarized approaches to the description and analysis of vegetation communities that were much debated in the 1950s and 1960s. The individualistic hypothesis favours a continuum view of vegetation, for which ordination rather than classification methods are appropriate. Compare organismic.