A hypothesis that a physical body in different inertial frames of reference can vary so that it can exist in one frame of reference and not exist in another has been considered. This substantiates the need to modify the principle of causality, as the principle of causality becomes applicable for events considered in the same inertial frame of reference only. As a result, informational isolation of inertial frames of reference arises. It has been shown that within the framework of this hypothesis physical bodies, from the viewpoint of observer, have properties identical across all frames of reference, despite existing differences. The special theory of relativity has been obtained as space-time transformations from the viewpoint of observer. The equations of special theory of relativity remain unchanged. A new type of transformations of space-time-fields emerges, complementary to space-time and fields transformations from the viewpoint of observer. The hypothesis may be viewed as a generalization of the special theory of relativity for the case where the principle of causality is applicable to the events considered in the same inertial frame of reference only.