The study of international relations is greatly defined by the schools of thought to which its figures adhere to. These schools of thought are theories on the practice of world politics, and act as lenses through which one can observe and analyze international affairs. Two particular theories have become extremely popular amongst intellectuals and practitioners alike: realism and liberalism. Both have their roots in ancient traditions of world politics, but two particular figures are most notable in these schools, Hans Morgenthau and Immanuel Kant, respectively. Each laid down the basic principles that have since become the hearts of each philosophy. There are a number of key, philosophical differences which separate Morgenthau and Kant, transcending them and shaping the schools of thought they helped to create. Hans Morgenthau's approach to world politics described individual states as the most important actors in international affairs, and believed in them as self-interested entities struggling with other states for dominance, with minimal concern for ethical issues and the political, economic or societal structures of individual countries. Immanuel Kant, on the other hand, believed that states, largely aided by international organizations, would profit from cooperation between each other, and deemed important the ideology of states, with special focus on the importance of liberal democracy for peace. Morgenthau utilizes a more descriptive analysis of world politics as it is in his eyes to reach his conclusions, while Kant arrives at his own by describing the world as he believed it should be.
Hans Morgenthau, the essential creator of modern realist thought, placed individual states above all other forces in the international stage, each dealing with the outside world not in terms of ideals, but in serving their own interests. The main goal of nations as the power-wielding .
entities of the world is to maximize their standings in respect to other nations.
