Spontaneous order, also named self-organization in the hard sciences, is the spontaneous emergence of order out of seeming chaos. It is a process in social networks including economics, though the term "self-organization" is more often used for physical changes and biological processes, while "spontaneous order" is typically used to describe the emergence of various kinds of social orders from a combination of self-interested individuals who are not intentionally trying to create order through planning. The evolution of life on Earth, language, crystal structure, the Internet and a free market economy have all been proposed as examples of systems which evolved through spontaneous order.Naturalists often point to the inherent "watch-like" precision of uncultivated ecosystems and to the universe itself as ultimate examples of this phenomenon.
Spontaneous orders are to be distinguished from organizations. Spontaneous orders are distinguished by being scale-free networks, while organizations are hierarchical networks. Further, organizations can be and often are a part of spontaneous social orders, but the reverse is not true. Further, while organizations are created and controlled by humans, spontaneous orders are created, controlled, and controllable by no one. In economics and the social sciences, spontaneous order is defined as "the result of human actions, not of human design."
Spontaneous order is also used as a synonym for any emergent behavior of which self-interested spontaneous order is just an instance.
According to Murray Rothbard, Zhuangzi (369–286 BCE) was the first to work out the idea of spontaneous order. The philosopher rejected the authoritarianism of Confucianism, writing that there "has been such a thing as letting mankind alone; there has never been such a thing as governing mankind [with success]." He articulated an early form of spontaneous order, asserting that "good order results spontaneously when things are let alone", a concept later "developed particularly by Proudhon in the nineteenth [century]".