Emergence
G.H. Lewes coined the term in Problems of Life and Mind (1875), distinguishing between resultant and emergent properties.
Resultant properties can be calculated from parts. The weight of a pile of bricks equals the sum of each brick’s weight. Simple addition.
Emergent properties cannot. Water is wet, but hydrogen and oxygen are not wet. Liquidity arises from the interaction of rigid molecules — none of which are liquid on their own.
The classic examples stack up:
Consciousness: Neurons fire. Enough of them, connected in the right ways, and something happens that no individual neuron exhibits. Subjective experience. The neural activity is measurable. The experience is undeniable. The connection between them remains philosophically contested.
Markets: Individual traders make individual decisions. The collective produces prices, trends, crashes — phenomena that exist only at the level of the market, not at the level of any participant.
Language: Words have definitions. Combine them in sequence and meaning emerges that no word carries alone. Poetry, humor, irony — properties of the arrangement, not the components.
Cities: Buildings, roads, people. The city is more than the sum of infrastructure and population. It has character, pace, culture — things that dissolve when you try to locate them in any single element.
Emergence limits reductionism. Knowing everything about the parts doesn’t automatically tell you about the whole. The interactions generate novelty.
Emergence remains understandable — just at its own level. Explanation must operate at multiple levels. Traffic patterns require traffic vocabulary, even though cars are made of atoms. The patterns are real. They require their own vocabulary.
The debate: strong vs. weak emergence.
Weak emergence: The higher-level property is unexpected but still, in principle, derivable from complete knowledge of the lower level. A surprise from our ignorance.
Strong emergence: The higher-level property has causal powers that are genuinely new — irreducible to lower-level causes even in principle. Consciousness, some argue, is like this.
The practical implication: systems exhibit behaviors that component analysis cannot predict. You can understand every module in a codebase and still be surprised by how the system behaves. You can know every person in an organization and still not understand its culture.
Wholes are what happens when parts interact.
Go Deeper
Books
- Emergence by Steven Johnson — Accessible introduction via ants, cities, and software. Johnson also wrote Where Good Ideas Come From, exploring the adjacent possible.
- At Home in the Universe by Stuart Kauffman — Self-organization at the edge of chaos. The Santa Fe Institute perspective.
- Complexity: A Guided Tour by Melanie Mitchell — The best modern overview. Clear, rigorous, readable.
- Complexity by M. Mitchell Waldrop — The story of the Santa Fe Institute and complexity science’s birth.
Essays
- Emergence (MIT Press anthology) — Classic philosophical and scientific writings collected.
Related: [[systems]], [[galls-law]], [[feedback-loops]], [[selection]], [[scenius]]