Glossary

Consolidated definitions of every term introduced across the chapters, alphabetical, each cross-referenced to the chapter where it’s elaborated. Intended as a quick-reference index and as raw material for the later image-schema grounding phase (see README.md).

Abstraction — the process of successively removing layers of detail from a representation to capture only a system’s most essential features. → 05

Adaptive system — a system whose course of development is the product of continuously acting on, and reacting to, feedback loops; complexity increases when two or more adaptive systems react to each other’s behavior over time. → 06, 10

Agency — the capacity to make choices directed at an internal goal or value; distinct from autonomy, which is only independence from other systems. → 03

Agent — an adaptive element of a complex adaptive system, acting on local information only, with no global view of the whole system. → 10

Allopoiesis — a system produced by something other than itself, according to a pattern imposed from outside (e.g. a factory producing tractors). Contrast Autopoiesis. → 03

Analysis — the traditional, reductionist method of reasoning: understand a system by breaking it into constituent parts, describing each in isolation, then recombining. → 01

Antifragility — a system’s capacity to actually improve as a result of disorder or stress, rather than merely resisting (robustness) or adapting to (resilience) it. → 10

Atrophy — the risk a closed system runs by resisting new inputs: it ceases to serve a useful function in its environment and may be deemed unnecessary. → 03

Attractor — a state, or set of states, that a dynamical system tends to settle into and return to after disturbance, regardless of many different starting conditions. → 10

Autonomy — the degree to which a system can function independently of other systems in its environment, made possible by its internal integrity. → 03

Autopoiesis — a system’s capacity to continuously reproduce and maintain its own components and organization from within, preserving its identity despite total turnover of its constituent matter (e.g. a living cell). Contrast Allopoiesis. → 03

Bifurcation — the point at which a system’s trajectory branches into a qualitatively new attractor rather than returning to its previous one. → 10

Black box — a system whose internal functioning is unknown or ignored; viewed purely in terms of its inputs and outputs. → 02

Boundary — the limit demarcating a system’s internal components and processes from its environment; where the nexus of relations enabling autonomous functioning reaches its limit. → 03

Bottom-up causality — the view that a system’s macro-level behavior is determined by the rules governing its micro-level elements. Contrast top-down causality. → 05

Causal loop diagram — a map of a system showing all constituent components and their interactions, revealing the structure of its feedback loops. → 06

Centrality — a measure of how structurally important a node is in a network: by degree (direct connections), closeness (short paths to everyone), betweenness (lies on many shortest paths), or eigenvector (connected to other well-connected nodes). → 09

Chaos (sensitive dependence) — the property of a deterministic, nonlinear system whereby arbitrarily small differences in initial conditions amplify into large differences in outcome, making long-run behavior practically unpredictable (the “butterfly effect”). → 10

Closed system — a system that resists incorporating new inputs across its boundary; more strongly defined by the static properties of the boundary itself. → 03

Cluster / Clique — a subset of nodes in a network far more densely interconnected with each other than with the rest of the network, often built on homophily. → 09

Co-evolution (“dancing landscape”) — the dynamic in which multiple adaptive agents adapt to each other simultaneously, so each agent’s fitness landscape keeps shifting as the others move across it. → 10

Complexity (as a graded property) — a system’s degree of complexity along at least four dimensions: number of elements, their diversity, their interconnectivity, and their capacity to adapt. → 02, 10

Conceptual models — the structures, shaped by our paradigm, through which we define and interpret every impression we receive; they shape what we see, which shapes what we do, which shapes the world we create, which feeds back to shape our conceptual models. → 01

Consumptive function — a function where the resource input transfers its energy to the system (which conserves it internally) while outputting entropy/waste to the environment. → 07

Control system — see Regulatory mechanism.

Cybernetics — the area of systems theory that studies regulatory mechanisms; designed to steer/guide a system toward the environmental parameters needed for homeostasis. → 06

Degree — the number of connections (edges) a node has in a network; the simplest measure of its local connectivity. → 09

Differentiation — a developmental process defined by the proliferation of subsystems and specialized elements within a system, increasing its capacity to respond to a greater diversity of environmental states. Its necessary counterpart is Integration; imbalance between the two, in either direction, produces negative synergy. → 04

Diffusion / Contagion — the process by which something spreads across a network; simple contagion needs only one exposure, complex contagion needs reinforcement from multiple sources or a threshold to be crossed. → 09

Dissipative structure / Far-from-equilibrium — organized, low-entropy structure sustained by continuous energy throughput rather than by settling into passive equilibrium (Prigogine). → 10

Downward causation — the higher/macro level of an emergent system exerting causal influence back down on its own lower-level substrate; the criterion that distinguishes strong from weak emergence. Contrast Epiphenomenon (pure upward causation). → 04, 05

Eco-system thinking — seeing every entity as interconnected with every other in a network of mutual influence, with no privileged center. Contrast Ego-system thinking. → 01

Edge (network) — a connection between two nodes, directed or undirected, weighted or unweighted. → 09

Edge of chaos — the narrow dynamic zone, between rigid order and chaotic disintegration, in which self-organization is most productive: enough variation to keep adapting, enough coherence to remain a functioning whole. → 10

Ego-system thinking — a self-centered view of the world in which connections are drawn only loosely, radiating out from oneself, without connections drawn between the other entities themselves. → 01

Element — the most basic level of the systems hierarchy: a part with no further constituent components, described only by its properties (e.g. an electron). → 05

Emergence — a process whereby larger entities, patterns, or regularities arise through interactions among simpler entities that do not themselves exhibit those properties; what results is qualitatively different from the parts, not just quantitatively greater. → 04

Encapsulation — nesting one model of a system inside another (which may itself be nested within a third, etc.), creating a hierarchical structure of representation. → 05

Energetics — the area of study concerned with energy across all physical systems (broader than thermodynamics), closely related to systems theory. → 07

Entropy — the incapacity to perform work; a measure of the degree of disorder within a system; the opposite of energy/resource; loosely, “waste.” → 07

Environment — the sum total of other systems and input/output resources that a system interacts with; everything outside a system’s boundary; defined relative to the system’s functioning. → 03, 05

Epiphenomenon — a phenomenon fully explainable by relations among lower-level features, assumed to exert no independent causal effect back on them; the product of pure upward causation. Contrast Downward causation. → 05

Epistemological emergence — emergence that is a limit of our knowledge/computing power (in practice we can’t derive the macro from the micro, though nothing prevents it in principle). Contrast Ontological emergence. → 04

Evolution (as a general process) — change, variety, selection, and replication, generalized past biology to markets, institutions, and technologies. → 10

Externality — an effect that lands on another agent or system without ever looping back to its own source; unlike feedback, not self-correcting, and typically requires outside governance. Contrast Feedback loop. → 06

Feedback loop — a channel or pathway formed by an effect returning to its cause, generating either more (positive) or less/opposite (negative) of the same effect. → 06

Fitness landscape — a spatial model of evolutionary search, where each point is a possible configuration and height represents fitness; search faces an explore-vs-exploit trade-off. → 10

Flow — the rate of change in a stock, measured over an interval of time. → 06

Function — a process that transforms energy or resources from one state to another, via input, process, and output; the defining feature that distinguishes a system from a mere set. → 02

Geodesic — the shortest path between two nodes in a network. → 09

Holism — the paradigm underlying Systems Thinking: understanding things within the context of the whole environment they’re part of, and how they are shaped by their nexus of relations. Contrast Reductionism. → 01

Homeostasis — the state in which a system’s internal variables are regulated to remain stable and relatively constant despite changes in its external environment; one attractor among several a system could settle into, not necessarily the default. → 06, 10

Homophily — the tendency of similar nodes in a network to connect to each other (“birds of a feather”), a common basis for clustering. → 09

Hub — a node with disproportionately high connectivity in a network, aggregating and distributing flow both locally and globally. → 09

Input — elements captured and assembled at a system’s boundary to be processed by its function; systems can only process a specific range of inputs. → 02

Integration — the process of recombining differentiated, specialized parts into a coordinated, functioning whole; forms a dialectic with Differentiation — each enables the other. → 04

Integrative levels (theory of) — the theory that units of matter are organized into levels of increasing integration and complexity, describing the evolution from the inanimate to the animate to the social world; higher levels are more complex, depend on and are made precarious by their lower-level building blocks, and have progressively fewer instances. → 05

Integrity — the degree to which a system’s parts are working together as an entirety, giving the system a degree of autonomy. → 03

Interference — a destructive relation: prevention of a process or activity from being carried out properly due to interaction between elements or systems, reducing the combined output below the sum of the parts. Contrast Synergy. → 04

Isolated system — a system that does not interact with its surroundings in any way; more restrictive than closed. → 03

Iterated (repeated) game — a game played repeatedly by the same agents, who can condition their next move on the others’ past behavior; unlike a one-shot game, this allows cooperative strategies (e.g. tit-for-tat) to outperform purely exploitative ones and stabilize as the long-run equilibrium. → 10

Model — an abstract, compact representation of a phenomenon, built by removing detail while retaining what’s essential; judged by usefulness, not by being “correct.” → 11

Nash equilibrium — a state in a game where no single agent can improve its own outcome by unilaterally changing strategy, given every other agent’s current strategy; not necessarily the best collective outcome (mutual defection is a Nash equilibrium in the one-shot prisoner’s dilemma even though mutual cooperation would be better for both) — this is why social dilemmas are stable traps rather than mere bad luck. → 10

Negative feedback loop — a feedback loop where linked elements change in opposite directions; typically associated with stable, sustainable development. → 06

Network effect — a network’s value grows disproportionately (often quadratically) with its number of connected nodes (Metcalfe’s law) — the diffusion dynamic viewed from the value side. → 09

Node — an entity, with properties, positioned within a network. → 09

Ontological emergence — emergence that claims the macro level is, in principle, irreducible to the micro level — a fact about the world, independent of any observer’s knowledge or computational limits. Contrast Epistemological emergence. → 04

Open system — a system that interfaces and interacts with its environment across a permeable boundary, exchanging materials, energy, information, or ideas. → 03

Order from noise / Order through fluctuations — the principle that random perturbations are the raw material self-organization amplifies into new order (von Foerster). → 10

Output — energy or resources produced by a system’s process that travel across its boundary back to the environment. → 02

Paradigm — the worldview underlying a theory’s assumptions and methods; the foundation shaping what we notice and how we build any theory. → 01

Path (network) — a sequence of edges connecting two nodes. → 09

Percolation threshold — the point below which nothing spreads system-wide across a network and above which the same local rule produces a qualitatively different, system-wide outcome; the network-diffusion counterpart of a phase transition. → 09

Perspective-taking — recognizing that any single observer, limited to one vantage point, naturally mistakes their own partial view for the whole; a precondition for systems awareness. → 01

Phase transition — a rapid or accelerated period in a system’s development on either side of which the fundamental parameters describing the system change qualitatively; mechanistically, a bifurcation triggered when feedback drives a system into a new attractor basin. → 04, 10

Positive feedback loop — a feedback loop where linked elements change in the same direction; typically associated with unstable, potentially exponential processes (“virtuous cycles”) likely to crash via overshoot. → 06

Preferential attachment — the mechanism (“rich get richer”) by which new nodes in a network preferentially connect to already well-connected ones, generating scale-free/power-law degree distributions. → 09

Process — the series of actions performed on an input to transform it into an output; may be cyclical, nested, or parallel rather than strictly linear. → 02

Process philosophy / Process ontology — the view that reality is ceaseless becoming, and any apparent stability (a structure, a boundary) is a temporary, self-sustaining pattern of process, not a fixed underlying substance (Heraclitus’s panta rhei). Contrast Substance metaphysics. → 01

Productive function — a function where a system performs work on an input resource, outputting a resource of greater value than it took in. → 07

Protocol — the specific channel, medium, and rules that let exchange succeed across a permeable boundary (e.g. a shared language, a shared network protocol). → 03

Punctuated equilibrium — development that proceeds as long stable periods (negative feedback) interrupted by short bursts of rapid, destabilizing change (positive feedback), rather than smooth incremental growth. → 10

Reductionism — the process of breaking down or reducing systems to their constituent parts, describing the whole primarily as the sum of these elements; historically anchored in the Mechanistic (Newtonian) paradigm. → 01

Reflexivity — the bidirectional relationship between our subjective conceptual categories and the world we perceive: mental models shape what we see, but what we see also reshapes the models. → 01

Regulatory mechanism / Control system — the mechanism by which a system monitors feedback and acts to maintain homeostasis within its target environmental parameters; formally composed of a sensor, controller, and actuator, and subject to requisite variety (Ashby’s Law: a regulator needs at least as many internal states as the states it must control). → 06

Relation — a connection or interaction between two or more components, through which matter, energy, information, or ideas are exchanged, binding the elements into interdependency. Not all relations carry equal structural weight — see Weak tie. → 04

Requisite variety — see Regulatory mechanism.

Resilience — a system’s capacity to absorb a disturbance and adapt into a new but still-viable state. Contrast Robustness (resist and stay the same) and Antifragility (improve because of the disorder). → 10

Resource — a stored form of energy; an ordered structure that enables a system to perform work. Opposite of entropy. → 07

Robustness (of a system’s state) — a system’s capacity to resist a disturbance and remain in its current state. See also network robustness (09) for the structural sense of the term. Contrast Resilience, Antifragility. → 10

Schema — a cognitive/conceptual framework used to classify, interpret, and predict, rather than a fixed stimulus-response rule; what separates a simple control system from an adaptive agent capable of learning. → 10

Second-order cybernetics — the recognition that an observer/regulator is part of the system it observes and regulates, so that observation is itself a feedback loop capable of modifying the observer’s own models. → 10

Self-organization — the process by which a system spontaneously develops coherent, system- wide structure out of purely local interactions among its elements, with no centralized controller. → 04, 10

Self-organized criticality — a brittle, over-organized state in which a system is poised so that a small, ordinary input can trigger a disproportionate cascade (e.g. a sandpile avalanche). → 10

Set — a group of objects that share no common function and exist independently of one another; described completely by the sum of its elements’ individual properties. Contrast System. → 02

Simple / Complicated / Complex (typology) — a classification by symmetry: simple systems have many symmetries (few rules generate the pattern), complicated systems have none (must be described part by part), complex systems interleave symmetry and asymmetry. → 04

Small-world phenomenon — the combination of high local clustering with surprisingly short average path length across a network (“six degrees of separation”). → 09

Social dilemma — an interaction that is individually rational but collectively destructive (e.g. the tragedy of the commons), typically arising from a zero-sum or externality-laden relation. → 04, 10

Strong emergence — emergence involving genuine downward causation: the phenomenon cannot be reduced to, predicted from, or traced back to the individual components even in principle, and requires genuinely new descriptive vocabulary at the higher level (e.g. consciousness, quantum entanglement). Contrast Weak emergence. → 04

Stock — any entity that accumulates or depletes over time; a variable measured as a quantity at a point in time — it would still exist if time stopped, unlike a flow. → 06

Substance metaphysics — the view that reality is made of static “things” with properties fixed at each instant, and process is secondary to that stable substance (Parmenides). Contrast Process philosophy. → 01

Subsystem — a set of elements that makes up a system, which is itself a component of a larger system. → 05

Synergy — a constructive relation: interaction or cooperation of two or more components producing a combined effect greater than the sum of their separate effects, favored by positive-sum relations. Contrast Interference. → 04

Synthesis — the foundational method of reasoning behind Systems Thinking: understanding an entity through the context of its relations within the whole it is part of. → 01

System — a composite entity of interconnected, interdependent elements arranged to perform some collective function; distinguished from a set by the presence of relations and shared function. → 02

System-of-systems — the hierarchical level at which a system (itself made of subsystems) is understood as one component within a still-larger system. → 05

Systems awareness — the reflexive recognition that how we see the world is shaped by our conceptual models/paradigm, not given objectively; the necessary starting point of Systems Thinking. → 01

Systems dynamics — the branch of systems theory that models how systems change over time via internal feedback loops and time delays. → 06

Systems efficiency — the ratio between the energy input to a system and the energy it outputs; note that what counts as “energy” vs. “entropy” is relative to context. → 07

Systems science — the interdisciplinary application of systems theory across scientific domains, emphasizing how domains fit together (e.g. system ecology, sociotechnical systems) over siloed specialization. → 08

Systems theory — the formal, internally-consistent language (like mathematics) used to describe systems of any kind, independent of any particular empirical subject matter. → 08

Thermodynamics — the area of study concerned with energy specifically in relation to heat (a subset of the broader concern of energetics). → 07

Top-down causality — the view that a system’s micro-level elements are governed by rules determined at the macro/whole-system level; one framing resolves this as the micro level answering “how” (what’s possible) and the macro level answering “why” (what’s selected). Contrast Bottom-up causality. → 05

Weak emergence — emergence involving only upward causation: the resulting phenomenon can, in principle, be traced back to, predicted from, and computed from the individual elements, given sufficient information (e.g. Conway’s Game of Life) — it’s just often too computationally expensive to do so in practice. Contrast Strong emergence. → 04

Weak tie — a comparatively infrequent connection bridging two otherwise-separate clusters of a network; disproportionately important for a system’s diversity and integration despite its low individual weight (Granovetter). → 04, 09

Zero-sum / Positive-sum game — a formal characterization of a relation: zero-sum (one side’s gain is exactly the other’s loss) favors interference; positive-sum (both sides can gain) favors synergy. → 04, 10