ABSTRACT
As so eloquently argued by Hamlet, existence is usually conceived as an either-or question; things either exist or they do not. When it comes to social groups, however, the situation is not so clear-cut. Existence can be quantified. Groups can exist more or less. This is the view expressed some 50 years ago by social psychologist Donald Campbell. Building on principles of Gestalt psychology, Campbell (1958) attempted to define the conditions under which an aggregate of individuals begins to be perceived as a group. The term entitativity was coined, which referred to “the degree of having the nature of an entity, of having real existence” (p. 17).
