This paper shows that, contrary to what is claimed in many grammars and analyses, the inessive case of Basque is not reducible to the expression of containment and neither does it operate as a generic/fuzzy marker that could denote any kind of configuration. By studying several important corpora (from 17th century to the present) we demonstrate that the inessive case can be used (as similar markers in other languages) for describing spatial relations involving containment, support or "integrated" landmarks/grounds (routines). From these observations, some predictions are made about the situations in which the inessive can express by itself the spatial relation between a trajector/figure and a landmark/ground and those where it will be necessary to call for additional linguistic material. Finally, the implications that a generic/fuzzy analysis of the inessive versus a disjunctive approach (containment, support, routines) may entail for language and cognition theory is briefly discussed.