As we know, any change and evolution is associated with complexity. The complexity increases when the rate of change increases. When the size and number of events that changed around us are increasing, the complexity is also apparent. In other words, complexity is a dependent variable which dependes on time. In order to determine the complexity, we need a purposeful, scientific, and defensible method. Moreover, we have to determine the law that illustrates in the best way the evolution of complexity. As much as the complexity in a major event has had a high degree of change, or the equilibrium lasted longer, the importance of that major event would be higher. Theoretical basis of this paper is based upon Entropy and Chi distribution law. The results of this paper can predict situation of 25 years later. According to the S diagram, analysis shows that the complexity of the nature of physical and social structure, with regard to the rational model, has grown and now has reached its midpoint.