In this article the author is going to answer the question, that intrigues many researchers of international relations and political science – is it possible to build a grand theory explaining actions and behaviours of political, and international, entities? International relations are distinguished from other disciplines of science by its special character: they are polyarchic, plural, complex and impulsive. Th€is is why we find here, exceptional in contrary to other, more mature disciplines, diversity of opinions and answers to the question – in what way international relations shall be build? Searching for the right answer the researchers of international relations have to cross borders of many disciplines, also using research methods of sociologists, historians, economists, lawyers, psychologists and anthropologists. €There is a similar problem with political science, as the political matter is widely interpreted and, depending on the researcher and the analysed political system, its scope is wide as when using so called largo sense in the totalitarian states, where even the choice of school for a child has a political character or as when using so called strict sense in the democratic systems.