They also believe in the possibility of distinguishing opinion and truth in politics- between what is considered true rationally and objectively, and supported by evidence that is illuminated by concrete reason.
The theory of realism is within the international relations that predict states will act in their interest in defiance of any moral consideration. This belief originates from human nature observation, and the selfish and a fiercely competitive perception of the people. Realism tends to regard the international arena as anarchic, which is governed by no authority overriding any sovereign states. According to realists, the primary interest of any state is its survival and towards that goal, it competes for the resources available.
Liberalisms optimistic view of international politics is based on three core beliefs common to all paradigm theories. They consider states as the main actors in international politics, they also believe that states characteristics do vary, and these have great effects on the behaviors of the states. In addition, they believe that some internal arrangements are preferable to others. For liberals, there are bad and good states.
The liberals treat states as the major actors in the global politics. Good states are believed to pursue policies of cooperation and hardly ever start wars, whereas states regarded as "bad" initiate conflicts with other states and were willing to use force to get their way. In contrast to liberals, Realists are pessimistic when it comes to global politics. They agree that it would be desirable to create a peaceful world, but they see no easy alternative of escaping the harsh reality world of security competition and war between countries. To them, creating a peaceful world is a good idea but not practical