Syncretism is used in many spheres of science, and namely in phylosophy, in psychology, in linguistics, in syntax. Syncretism means a "reunion" of some grammatical categories and significances. It's a phenomenon that leads to confusion of cases, being a condition of formal undiferention of them, maintaining the differences of the meanings. At the base of syncretism is the notion of significance. In syntax no approach can be undertaken without semantics or logic. Especially these two aspects compile the substance of the communicative act.