Thus the identity of an object is implicitly given by the set of states in which we recognize it to be the same. The concept of object group is extremely general, as it should be, in view of the vast ...Thus the identity of an object is implicitly given by the set of states in which we recognize it to be the same. The concept of object group is extremely general, as it should be, in view of the vast range of situations it is meant to cover. First, the same object may be observed by different inertial observers whose findings are connected by the transformations of the inertial group, to be called also the passive kinematic group.