ABSTRACT
The variation of political systems from the rule of one to the rule of many has interested political philosophers and political scientists since Plato and Aristotle. They have attempted to unravel the origins of autocracy, democracy and other political systems, to find out what kinds of social conditions are connected with various types of political systems, and to clarify causal relations between political systems and environmental conditions. Many of these studies have concerned the conditions or prerequisites of democracy. There are numerous theories and explanations of democracy and democratization, but it has been difficult for researchers to agree on the most appropriate theoretical interpretation of democratization or on the causal factors of democratization. Thus this crucial research problem is still open. Various theoretical approaches compete with each other.
