Emergence
the principle that entities exhibit properties which are meaningfully only when attributed to the whole, not to its parts SEBoK pg153
A great evocative example of emergence:
Bird example 🦅
Feathers, beaks, wings, and gullets do not have the ability to overcome gravity; however, when they are properly connected to a bird, the create the emergent behavior of flight.
SEBoK pg153
Emergence is a macro-level property of systems, in particular complex systems.
Emergence is ultimately what we’re going for when we create systems. The types of emergence we “expect” and design the system to accomplish are called simple emergence. There are, however, often (or always) unexpected emergences, called strong emergence. These can be difficult-to-impossible to predict and can be catastrophic. Iteration is the Only Effective Method of Controlling Emergence.