Seven is the magic number in nature

Thomas Saaty
Joseph M. Katz Graduate School of Business
University of Pittsburgh
United States

Publication date: Dec, 2016

Journal: Proceedings of the American Philosophical Society
Vol.: 160- Issue: 4- Pages: 335-360

Abstract: Where there is structure, the parts of the structure must function together with a degree of consistency and purpose. Specifically, I am thinking of dynamic systems in which there are action and reaction among the parts and their functions and also friction and resistance. Natural systems, such as the cells in our bodies, and man-made systems, such as a watch, are constructed in a hierarchic way so that the different parts in each level work together consistently-that is, each group performs a function to fulfill some purpose. Thus, the number of functions working together determines the structure through which materials or energy pass. The number of functions that can work together is determined by the consistency of the interactions of these functions. Conversely, consistency among the functions depends on the number of interacting components; if there is a large number, the possibility of inconsistency is greater. How large should the number of functions be to fulfill a purpose? The answer given here has important implications for constructing both physical and social systems. The current paper shows with mathematics supported by examples that 7 to 8 seem to be the maximum number for any component of a complex system.

Keywords: Seven, Dynamic systems, Consistency