Emergent entities are properties, patterns or substances which 'arise' out of more fundamental entities through an emergence process. A property of a system is emergent, if it is not a property of any fundamental element. It is a property of the collection, of the whole system, and arises from the interactions of the individual elements. An emergent property - like a society - consists of the interrelated individuals who compose and have composed it.
- "Emergent properties are collective properties, which means they are properties of collections, not properties of individual parts. The cause can often be traced back to the interactions between the parts of which a system is made." ~ Raima Larter
By this criterion alone, most properties are emergent, as Daniel Little argues: "the sweetness of sugar, the flammability of woven cotton, the hardness of bronze". One could add the liquidity of water, the elasticity of rubber, or the rigidity of iron. Daniel Little argues that emergent properties exist in various degrees: the weakest form is mentioned above, if an emergent property of a system is just a property or capability that is not possessed by its parts. A form of weak emergence.
If one adds the constraint that the property cannot be derived, even in principle, from facts about the components and their arrangements within the structure in question, then only a few properties exist. This is a form of strong emergence. Somewhere in between are emergent properties where it is possible to infer the properties of the whole, but not a trivial matter to do so. Daniel Little says they are typical for complex systems, and gives the following quote from Herbert Simon from his article "The Architecture of Complexity"
- "Roughly, by a complex system I mean one made up of a large number of parts that interact in a nonsimple way. In such systems, the whole is more than the sum of the parts, not in an ultimate, metaphysical sense, but in the important pragmatic sense that, given the properties of the parts and the laws of their interaction, it is not a trivial matter to infer the properties of the whole. In the face of complexity, an in-principle reductionist may be at the same time a pragmatic holist." ~ Herbert Simon
Emergent entities are not reducible. Although they arise out of more fundamental items, they are 'novel' or 'irreducible' with respect to them. Emergent properties are dependent on underlying processes, and yet independent from underlying processes. This is the paradox of emergence.
The difference between the different terms is:
- Emergent Property: A property of a system is emergent, if it is not a property of any fundamental element. If a property is not necessary (or does not appear) in the description of all properties of the fundamental elements, elementary actors or basic building blocks, it can only be an emergent property.
- Emergence: Emergence is the appearance of emergent properties on a higher level of organization without central organizer. It can be observed in complex systems due to the pattern of interactions between the elements of a system over time.
- Entity: Emergent properties lead to the appearance of new entities and objects on a larger scale. They play an important role in the definition of general terms like being, entity and substance. Russ Abbott defined an entity as follows: "An aggregation counts as an entity if it has emergent properties", see his talk Emergence and Entities
Agent based Models
The basic agent-based models explain the emergence of fundamental properties:
- Boids Model: swarms
- Dissemination Model: culture
- Segregation Model: ghettos and segregation
- Tribute Model: power
- El Farol Bar Model: chaos