> [!summary] Progressive Summary # Structured Notes ## Definitions ## Chapter Summaries ### Chapter 3 - Rules of Complexity and the Adjacent Possible #### Rule 1 - Numbers Matter > There must be a sufficient number of interacting parts to form a complex system. The standard mail-order ant farm has twenty-five or so ants, all hard at work digging tunnels, creating food lines, and establishing a cemetery for ants that die. These behaviors are examples of emergent phenomena. But once you have just a handful of ants left, there is no self-organization and the emergent properties dissolve: no food lines, no cooperative tunnel building, and dead ants stay where they die. On the other hand, the more individuals there are in the system, the greater the level of complexity. A colony of two hundred ants is not as complex as one with two thousand ants, and one with twenty thousand ants is still more complex. A village is not a city is not a megalopolis. #### Rule 2 - Interactions are Local, Not Global Every emergent complex system - brains, ant colonies, social structures - are made of local interactions. > So, who is in charge of whom? Ultimately, no one ever is; all interactions are local. Every element of a complex system interacts with every other element through networks made up of local connections. Some elements may have greater or lesser influence, but none are truly above and beyond the web; none reach down into it from outside with inexorable intent, exerting total control. #### Rule 3 - Negative Feedback Loops Prevail > All living systems are homeostatic, yet they are never frozen still. Similar to that stability-in-movement we saw in chaotic systems, there is ceaseless change in complexity, continual oscillation within the healthy, life-sustaining ranges. Life is ceaseless movement; stability is found in balance, not rigidity. #### Rule 4 - The Degree of Randomness Is Key > Too much randomness prevents any self-organization at all, while too little randomness causes a system to behave more like a machine, without enough flexibility to find new modes of adaptive behaviors. With just the right, low level of randomness, sometimes referred to as quenched disorder, the system blooms with the ability to explore what Stuart Kauffman calls the “adjacent possible.” > In complexity, the same starting conditions, continually subject to some low-level randomness, are unlikely ever to evolve in precisely the same way. It is as though in every moment of its life, a complex system is enveloped by a shimmering cloud of adjacent possibles, all the possibilities that might evolve in the very next moment. And then in that moment, one unpredictable possibility manifests from all those available. This new iteration of the complex system now faces new conditions coupled with that limited randomness, and a different cloud of potentials manifests around it. And then again. And again. And again. Moment after moment after moment. #### Death and disorder > While the physical phase transitions between liquid water and ice and vapor are best thought of as simple lines, the boundaries at the edge of chaos are fractal. Imagine a (mathematical) boundary that looks as infinitely intricate and filigreed as the fractals of the Mandelbrot set. Biological creativity arises within a realm shaped by fractal geometry, where stability and chaos tug at life from either side. > > With quenched disorder leading us down twists and turns of the fractal path at the boundary between stability and chaos, we may wind up in places we would prefer to avoid. Instead of remaining within this fractal phase transition in which we find life, we might be led out of it, either into rigid, machinelike determinism or into chaos. Either way the tug-of-war resolves, the self-sustaining, adaptive creativity of the system is lost, and it will undergo a partial or complete mass-extinction event. > > Thus, the limited randomness that is the source of creativity in complex systems, and in all life, will inevitably lead to partial mass-extinction events and, eventually, given enough time, the death of the entire system. What makes us alive necessitates that we will die. There is no such thing as eternal life or a fountain of youth. > > Though this may sound grim for us as individuals, from a larger perspective, is it? Mass extinctions always make way for new emergent forms. Without the extinction of dinosaurs, would mammals have risen to prominence? Without the Black Death in Europe, would there have been a Renaissance? Death clears the way for more extraordinary, unpredictable life. And isn’t there more to life than just staying alive? What about the meaning of being part of a larger, ever-evolving whole? ### Chapter 4 - The Cellular Level: Our Bodies, Our Cells #### Complementarity > Whether something looks like a thing or like a phenomenon arising from smaller things depends on your scale of observation, your perspective or point of view. > This duality might leave you feeling a bit unsettled. “At the end of the day,” you might ask, “which is it really, fundamentally?” Is your body a unitary entity or is it a phenomenon arising from its smaller parts, the interacting cells? The answer is, of course, both, equally and unequivocally. > > This kind of doubling of reality is a form of what quantum physicists call a complementarity. Perhaps the most famous example of complementarity is embedded in the now well-known, if perhaps not well-understood, notion that “light is both a wave and a particle.” Niels Bohr coined the term "complementarity" in 1928. > Furthermore, Bohr saw complementarity as a fundamental property of existence at every scale. It was so central to his thinking that, when he was awarded Denmark’s highest honor, the Order of the Elephant, he designed a coat of arms for himself that featured a perfect symbol for complementarity, the yin-yang. Alas, perhaps due to the increasing subspecialization across all fields of science as the twentieth century rolled forward, these ideas about generalized complementarity were explored only in small corners of philosophy and science. Nonetheless, they remain very much alive. > The teeming hordes of living things on Earth, not only in space but in time, are actually all one massive, single organism just as certainly as each one of us (in our own minds) seems to be a distinct human being throughout our limited lifetime. > > Thus, we have yet another complementarity: each of us is, equally, an independent living human and also just one utterly minute, utterly brief unit of a single vast body that is life on Earth. From this point of view, the passing of human generations, in peace or turmoil, is nothing more than the shedding of cells from one’s skin. ### Chapter 5 - The Molecular Level: Beyond the Cell Doctrine # Quotes