Complexity Science, Rules of the Whole Systems and the Qualitative Researches

For complex systems, rules of the whole systems should be investigated. Consequently, appropriate attention should pay to the qualitative researches. In this paper, a representation (E):Sni=11i=E(n) is given. It means: self-clustering, self-organizing and evolving to a new level. (E) is used to describe the formation of the structures of complex systems and their dynamic behavior. The concept ‘self-clustering’ is explained. The effect of clustering quantity to system ability is analyzed. Another representation (C):11+12+…+1nen 2 is followed. Many examples in different domains, such as in biology, natural world, social science, economics, engineering, etc, are given which can be explained by (E). From the standpoint of complex systems and with the aid of (E), the understanding of ‘from quantitative change to qualitative change’ is discussed. Finally, by comparing the self-similarity in the structures of complex systems with that in fractal, we can see that the complex structures are formed by repeating some simple rule again and again, so complexity is besides in simplicity. Moreover, self-clustering, self-organizing and repeating is the basic rule to form the structures of a kind of complex systems.