Organic chemistry is the study of the structure, properties, and reactions of...
When one is discussing isomers, they are talking about compounds that have something in common (their molecular formula) and also the way in which these isomers differ in a fundamental way. In the case of configurational isomers, the idea is that constraints placed in molecules by covalent bonds create alternatives in the way that atoms are arranged in three-dimensional space.
Unlike Constitutional Isomers which can differ tremendously, configurational isomers do not. The possess the same names since they are constituted the same.