lémergence

Emergence, sometimes written as l'émergence in French, refers to properties or behaviors that arise at a higher level of organization from interactions among lower-level components and are not straightforwardly predicted from the properties of those components alone. Emergent phenomena are studied across physics, biology, computer science, economics, and sociology. They challenge simple reductionist explanations by showing how organization and dynamics at one scale can produce qualitatively new features at another.

Two broad senses are common: weak emergence, where macro-scale outcomes are computable or definable from micro-scale rules but may be unpredictable in practice; and strong emergence, which posits ontologically novel properties that are not deducible from lower-level laws, sometimes accompanied by downward causation.

Examples include: phase transitions and temperature as emergent properties of many-particle systems; flocking and swarming behavior from local interaction rules; pattern formation in reaction-diffusion systems (Turing patterns); traffic flow and market dynamics yielding collective patterns; consciousness or life as debated emergent properties of neural or chemical networks. In computation, cellular automata show how simple rules generate complex behavior and information processing.

Methodologically, emergence is closely linked to self-organization, complex systems, and network theory. Critics argue that even strong emergence can be reconciled with a comprehensive theory if future laws or principles are found, while others maintain that certain macroscopic features are causally autonomous.