Book Summary: “Emergence: the Connected Lives of Ants, Brains, Cities and Software” by Steven Johnson


“Emergence: the Connected Ants, Brains, Cities and Software” by Steven Johnson

Title: Emergence: the Connected Lives of Ants, Brains, Cities and Software
Author: Steven Johnson
Scope: 4 stars
Readability: 4.5 stars
My personal rating: 5 stars
See more on my book rating system.

Topic of Book

Johnson explores that role of complex systems, such as ant colonies, the human brain, cities, slime mold and the internet that emergence from simple behaviors at a lower level.

Other books by the same author

Key Take-aways

  • Complex systems in both the human and animal worlds can emerge from very simple individual behaviors.
  • These bottom-up systems are more innovative and enduring than top-down centralized systems.
  • They consist of individuals solving local problem while in communication with many other individuals doing the same. The interactions between the individuals is what creates the emergence of a higher order.

Important Quotes from Book

“People had been thinking about emergent behavior in all its diverse guises for centuries, if not millennia, but all that thinking had consistently been ignored as a unified body of work—because there was nothing unified about its body.”

“some of the great minds of the last few centuries—Adam Smith, Friedrich Engels, Charles Darwin, Alan Turing—contributed to the unknown science of self-organization, but because the science didn’t exist yet as a recognized field, their work ended up being filed on more familiar shelves. ”

“What features do all these systems share? In the simplest terms, they solve problems by drawing on masses of relatively stupid elements, rather than a single, intelligent “executive branch. They are bottom-up systems, not top-down. They get their smarts from below. In more technical language, they are complex adaptive systems that display emergent behavior. In these systems, agents residing on one scale start producing behavior that lies one scale above them: ant colonies, urbanites create neighborhoods… The movement from low-level rules to high-level sophistication is what we call emergence.”

“Emergent complexity without adaptation is like the intricate crystals formed by a snowflake: it’s a beautiful pattern, but it has no function. The forms of emergent behavior that we’ll examine in this book show the distinctive quality of growing smarter over time, and of responding to the specific and changing needs of their environment.”

 “While there’s no single key to the success of the social insects, the collective intelligence of the colony system certainly played an essential role. Call it swarm logic: ”

“Local turns out to be the key term in understanding the power of swarm logic. We see emergent behavior in systems like ant colonies when the individual agents in the system pay attention to their immediate neighbors rather than wait for orders from above. They think locally and act locally, but their collective action produces global behavior.”

“Organized complexity, on the other hand, is like our motorized billiards table, where the balls follow specific rules and through their various interactions create a distinct macro-behavior, arranging themselves in a specific shape, or forming a specific pattern over time.”

“While there’s no single key to the success of the social insects, the collective intelligence of the colony system certainly played an essential role. Call it swarm logic.”

“If you’re building a system designed to learn from the ground level, a system where macro-intelligence and adaptability derive from local knowledge, there are five fundamental principles you need to follow:

  1. More is different… the statistical nature of ant interaction demands that there be a critical mass of ants for the colony to make intelligent assessments of its global state.
  2. Ignorance is useful… Emergent systems can grow unwieldy when their component parts become excessively complicated. Better to build a densely interconnected system with simple elements and let the more sophisticated behavior trickle up.
  3. Encourage random encounters. Decentralized systems such as ant colonies rely heavily on the random interactions of ants exploring a given space without any predefined orders. Their encounters with other ants are individually arbitrary, but because they are so many individuals in the system, those encounters eventually allow the individuals to gauge and alter the macro-state of the system itself.
  4. Look for patterns in the signs… This knack for pattern detection allows meta-information to circulate through the colony mind.
  5. Local information leads to global wisdoms. This may well be the most important lesson that the ants have to give us. (p77-78)

“The persistence of the whole over time—the global behavior that outlasts any of its component parts—is one of the defining characteristics of complex systems. Generations of ants come and go, and yet the colony itself matures, grows more stable, more organized. The mind naturally boggles at this mix of permanence and instability.”

 “There are manifest purposes to a city – reasons for being that its citizens are usually aware of: they come for the protection of the walled city, or the open trade of the marketplace. But cities have a latent purpose as well: to function as information storage and retrieval devices… “Cities bring minds together and put them into coherent slots. Cobblers gather near other cobblers, and button makers near other button makers. Ideas and goods flow readily within these clusters, leading to productive cross-pollination, ensuring that good ideas don’t die out in rural isolation… “The neighborhood system of the city functions as a kind of user interface for the same reason that traditional computer interfaces do: there are limits to how much information our brains can handle at any given time. We need visual interfaces on our desktop computers because the sheer quantity of information stored on our hard drives… Cities store and transmit useful new ideas to the wider population, ensuring that powerful new technologies don’t disappear one they’ve been invented.” (p109)

“Europe underwent a transition not unlike that between H2O molecules changing from fluid state of water to the crystallized state of ice: for centuries, the population is liquid and unsettled –  and then, suddenly, a network of towns comes into existence… what spread through Europe, starting around AD 1000, were a series of technological advances that combined to produces a dramatic change in the human capacity for harnessing energy flows.” (p110-112)

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