In this chapter, it is argued that there is Self-Organization whenever a process of encounter and interaction of actually distinct elements, without the intervention of a supervisor (or at least an omnipotent supervisor), tends to the constitution of a global form or “whole”. This form essentially results from interaction itself and, only to a lesser degree, from the starting conditions or from an interchange with the environment. The process begins with the meeting of independent causal lines (as in Cournot’s concept of chance), and during this process, causal factors interact and generate a new system with a functional organization. The process does not follow a previously established goal, but generates its own goals. Therefore, the concept of teleology that arises from the study of self-organizing systems is different from the traditional vitalist viewpoints (such as Driesch’s concept of entelechy) and is compatible with the Darwinian view of biological evolution without a previously established direction.