Emergence is the process of deriving some new and coherent structures, patterns and properties in a complex system. Emergent phenomena occur due to the pattern of interactions between the elements of a system over time. Emergent phenomena are often unexpected, nontrivial results of relatively simple interactions of relatively simple components. What distinguishes a complex system from a merely complicated one is that some behaviours and patterns emerge in complex systems as a result of the patterns of relationship between the elements.
An emergent behaviour or emergent property is shown when a number of simple entities (agents) operate in an environment, forming more complex behaviours as a collective. A system made of several things can host properties which the things themselves do not have. For instance, consider two points on a plane. These points will have a distance between them. This distance is not itself a property, but exists in the relation between the points. Emergent properties can arise not only between things in the system, but between other emergent properties. The number and subtlety of these properties can be very much greater than the number of things.
The complex behaviour or properties are not a property of any single such entity, nor can they easily be predicted or deduced from behaviour in the lower-level entities. The shape and behaviour of a flock of birds or school of fish are readily understandable examples, and it is typical that the mechanisms governing the flock or school are harder to grasp than the behaviour of individual birds or fish.
This helps to explain why, for instance, the number of ways of packing boxes into a truck increases exponentially with the number of boxes and why the fallacy of division is a fallacy. According to an emergent perspective, intelligence emerges from the connections between neurons, and from this perspective it is not necessary to propose a "soul" to account for the fact that brains can be intelligent, even though the individual neurons of which they are made are not.
Emergent structures are patterns not created by a single event or rule. There is nothing that commands the system to form a pattern, but instead the interactions of each part to its immediate surroundings causes a complex process which leads to order.
A good example is an ant colony. The queen does not give direct orders and does not tell the ants what to do. Instead, each ant evaluates what job it should be doing by seeing what other ants are doing, blindly follows pheromone trails, and never receives an order. Here each ant is a self-governing unit that makes choices depending only on what it 'sees'. Despite the lack of hierarchy of command, ant colonies exhibit complex behavior and have even been able to demostrate the ability to solve geometric problems (the ants' colonies find the maximum distance from all colony entrances to dispose of bodies.)
Emergent structures also include cities and many natural phenomena including the shape of galaxies. Because they form order despite the lack of command, emergent structures may appear to defy entropy principles.
Emergent processes or behaviours can be seen in many places, from any multicellular biological organism to traffic patterns or organizational phenomena to computer simulations and cellular automata. The stock market is an example of emergence on a grand scale. As a whole it precisely regulates the relative prices of companies across the world, yet it has no leader; there is no one entity which controls the workings of the entire market. Each agent, or investor, has knowledge of only a limited number of companies within their portfolio, and must follow the regulatory rules of the market. Through the interactions of individual investors the complexity of the stock market as a whole emerges.
- Dynamical system
- Chaos theory
- Complex systems
- Emergent algorithms
- Mass action
- Neural networks
- Society of Mind theory
- Systems thinking
- Emerging Church
- Gregory Bateson, Steps to an Ecology of Mind (1972) Ballantine Books, Inc., New York, N.Y.
- Steven Johnson, Emergence (2002)
- Kevin Kelly, Out of Control (1994)
- Stephen Wolfram, A New Kind of Science (2002), ISBN 1579550088.
- John H. Holland, Emergence from chaos to order 1998 Oxford University Press
- Mario Augusto Bunge, "Emergence and Convergence" (2001)