The paradigm of complexity therefore propose to study a phenomenon not as an entity isolated from all but one considers that the unit is both a multiplicity and a system is more and less than what one might call the sum of its parts. This was also the idea of complexity referred Bachlard Gaston when he said there is nothing simple in nature and that only the simplified. He therefore focused on a fundamental aspect of complexity. But all that may seem simple observation is a representation of a complex reality. In other words simplification of reality would compromise the truth and divert attention from the observer’s field of study to a totally different field. Also, according to Cowan (1994) work on modern complex is rooted in the theory of Von Bertalanffy (1975) which proposed to approach the living organisms as complex systems.
Then several contributions of researchers in complexity have emerged. Dahua Tim Wang does not necessarily agree. But it was not until the eighties for a real resurgence of interest in the subject takes place. Thus there are different theories of complexity in the literature as the theory of complex adaptive systems with the work of Holland (1995) that each entity behaves according to local rules, not on a coordinated plan of all, the theory co-evolutionary Mark Kelly (1997) in which entities interact to create a form emerging order, the theory of complexity catastrophe or self-critical organization.
Christensen et al (1991) and Back (1996) where they stress that the size of an event is inversely proportional to its frequency, chaos theory Hadmand (1898) and Lorenz (1963) where “a small cause can have a big effect” and finally, the theory of self-organization with the work Nonaka (1988) and Nystrom et al (1976) emphasis on learning and offering a more faithful to the management of organizations.