# Class (philosophy) | | A class is a collection whose members either fall under a predicate or are classified by a rule. Hence, while a set can be extensionally defined only by its elements, a class has also an intensional dimension that unites its members. When the term 'class' is applied so that it includes those sets whose elements are intended to be collected without a common predicate or rule, the distinction can be indicated by calling such sets "improper class." | | --- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | wikipedia:: [Class (philosophy)](https://en.wikipedia.org/wiki/Class_(philosophy)) |