The main theories of recognition in the field of international law are summarized as below :
According to this theory, only a recognized state obtains statehood and rights are granted in international fields. It is such a process by which a potential entity under international law by becoming a member of the international community acquires international personality. The main exponents of this theory are Hegel, Angilotti and Oppenheim. According to Oppenheim, a state is and becomes an international person, by recognition only and exclusively. Holland is also a proponent of constitutive theory. According to him, recognition gives maturity to States and when a State is not recognized, as a member of the community of States, it obtains no rights.
Declaratory or Evidentiary Theory
According to this theory, the statehood or authority of a new state or government exists even before recognition and does not depend on recognition. According to this doctrine, recognition is a formal acceptance by which an established fact is accepted. By recognition, only a declaration is made that a State is full of defined elements of a State as prescribed by international law. Among the proponents of this theory are Hall, Wagner, Brierly, Pitt Cobbet and Fisher. According to Hall, any state, becomes a member of the community of states as a matter of right only when it gets statehood. According to Pitt Cobet, this subject is subject of reality. According to him, if in a political state, there are all the necessary elements of a statehood, then formal recognition will not be an essential condition for obtaining obligations and rights under the International Law.
Legal scholars have also criticized the declaratory theory of recognition. To say that the recognition is simply a declaratory act does not seem entirely appropriate. States respect this doctrine very much. In fact, when a state is granted recognition, it is simply a declaratory function. But after granting recognition, its effects on the state are of such a nature that they are qualified as constitutive. According to Kelsen, recognition is constitutive when it confers on a State an international personality, it is also declaratory because it simply declares the potentials and the elements of a State which it already possessed by recognizing them as a State giving it the ability to enter the staes community.