Systems & Complexity

A set of interacting or interdependent entities, real or abstract, forming an integrated whole that together are able to respond to environmental changes or changes in the interacting parts, in a way analogous to either continuous physiological homeostasis or evolutionary adaptation in biology.

A model, prototype, statement, pattern of behavior, which other models, objects, statements, copy or emulate, often as a derivative of this canonical example.

The notion that the degree of control of a system is proportional to the amount of information available. In other words, one needs an appropriate amount of information to control any system, whatever it is.

The study of how people explain the causes of behavior and events — whether they credit internal traits or external circumstances.

A system that continuously regenerates and maintains itself from within. Living cells are the classic example — they produce the very components that sustain them.

In software, refers to a system with no recognizable structure or lacks a coherent architecture.

The imitation of models, systems, and characteristics found in nature, often for the purpose of solving complex human problems such as environmental tolerance, self-assembly, and the harnessing of solar energy.

A blending of elements drawn from two previously unrelated domains into a new pattern of association.

A system or device whose inner workings are opaque and whose internal workings can only be guessed at through its inputs and outputs.

An anecdote describing a frog in a pot of water where the water's temperature is gradually raised to the point of killing the frog without their noticing, but if the frog is placed instantly in hot water, it would jump out immediately.

The erroneous assumption that low-income and developing economies harbor an irrational attachment to livestock which hinders economic investments, whereas in fact the investment in livestock is a very rational and complex calculation of resource investment, power and esteem, gender, and familial ties.

The notion that a connection implies causality, with one earlier event being the cause of a subsequent event.

A process in a system of interconnected parts in which the failure of one or few parts can trigger the failure of other parts and so on. Such a failure may happen in many types of systems, including power transmission, computer networking, finance, human body systems, and transportation systems.

A system composed of many components which may interact with each other. Examples of complex systems are the human brain specifically, and many biological systems generally, transportation or communication systems, social and economic organizations (like cities), and the whole universe.

The tendency to favor complex explanations or solutions over simpler ones, even when simplicity is more accurate or effective.

A term for the process of an industrial cycle that revolutionizes the economic structure with periodic extinction of industries as new industries emerge to meet societal needs.

The notion that a sufficient number of adopters of an innovation in a social system is required such that the rate of adoption becomes self-sustaining and creates further growth.

A loss of economic efficiency that occurs when an equilibrium state for a good or service is not achieved or is not achievable.

Software design principle that advocates for high-level modules to depend on abstractions, rather than on low-level modules, to allow for flexibility, maintainability, and scalability of the system.

A network architecture where no single node is in charge — components and data are spread across many sources, making the system more resilient.

The cumulative effect produced when one event sets off a series of similar events. The term is best known as a mechanical effect, and is used as an analogy to a falling row of dominoes, and typically refers to a linked sequence of events where the time between successive events is relatively small.

The principle to build systems which rely on repetitive patterns and subsystems in efficient ways to avoid duplication and inefficiency.

The way complex patterns, behaviors, or properties arise from the interaction of simpler parts that don't individually display those qualities — like how consciousness arises from neurons, or a murmuration from individual starlings.

The view that every entity has a set of attributes that are necessary to its identity and function.

A shift in the function of a trait during evolution. For example, a trait can evolve because it served one particular function, but subsequently it may come to serve another.

A pattern of reasoning where one cause of an effect explains that effect entirely thereby reducing (need not eliminate) the need to verify other alternative causes.

An algorithm that uses feedback to multiplicatively decrease the rate of some process, in order to gradually find an acceptable rate.

The error of assuming that what's true for one part must be true for the whole. One strong player doesn't guarantee a strong team.

Assuming that there is one, simple cause of an outcome when in reality it may be caused by a number of only jointly sufficient causes.

The loop or circuit that forms when outputs of a system are routed back as inputs, as part of a chain of cause-and-effect.

First order effects directly follow from a cause, while second order effects follow from first order effects.

The design principle that as the flexibility of a system increases, its usability decreases. The tradeoff exists because accommodating flexibility requires satisfying a larger set of requirements, which results in complexity and usability compromises.

In aviation, a system that replaces the conventional manual flight controls of an aircraft with an electronic interface.

Outcomes are asserted to have been caused by the misconduct or wrongdoing of decision makers.

A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works and cannot be patched up to make it work. You have to start over with a working simple system.

The ability of a system, machine, or product to maintain a limited functionality even when a large portion of it no longer works or has broken down.

The condition of existing in grains or granules, referring to the extent to which a material or system is composed of distinguishable pieces. It can either refer to the extent to which a larger entity is subdivided, or the extent to which groups of smaller indistinguishable entities have joined together to become larger distinguishable entities.

Embedding data directly into the source code of a system, whereas 'soft code' embeds data in external locations or configuration files. These two coding practices have tradeoffs of time to develop, scaling, and sustainability.

The tendency to be overconfident in predictions when data seems to form a coherent story, even when that data is unreliable or incomplete. Pattern recognition feels like insight but can be misleading.

The study of decisions in transactions where one party has more or better information than the other. This asymmetry creates an imbalance of power in transactions, which can sometimes cause the transactions to go awry, a kind of market failure in the worst case.

When network participants pass on information they assume to be true, but cannot know to be true, based on information on what other users are doing.

A system built within an existing platform (due to constraints, preferences, etc.) that has become so complex that it has become a poor replica of an existing platform.

The concept that flawed, incorrect, or nonsense input data produces flawed, incorrect, and nonsense output.

A learning process through which the strength of a behavior is modified by reinforcement or punishment.

The property of remaining unchanged despite changes in conditions or perspective. In science and math, invariants reveal the deep structure beneath surface variation.

The observation that improvements in the efficiency of resource use often lead to increased total consumption of that resource rather than decreased consumption. As efficiency lowers the effective cost per unit, demand rises enough to offset or exceed the original savings.

An aphorism that "no matter who you are, most of the smartest people work for someone else."

A workaround or quick-and-dirty solution that is clumsy, inelegant, inefficient, difficult to extend and hard to maintain, yet nonetheless is operational.

In statistics and decision theory, the risk that results when a statistical model assumes the normal distribution, but is applied to observations that have a tendency to occasionally be much farther (in terms of number of standard deviations) from the average than is expected for a normal distribution.

A fundamental principle of gestalt which says that people will perceive and interpret ambiguous or complex images as the simplest form(s) possible.

The principle that when a system in equilibrium is disturbed, the system will adjust itself in such a way that the effect of the change will be reduced or moderated.

A notion of thinking which provides a counterpoint to what it views as today's "faster/cheaper" mindset and to promote "slower/better" thinking.

In statistics, a model which describes a distribution of occurrences where a large portion of the distribution are far from the "head" or central part of the distribution. Often applied in a business, to apply to business models that can offer many different varieties of uncommon goods (Amazon or Netflix), as opposed to few varieties of common goods (Walmart).

Major factors explain major portions of the results, where minor factors explain only minor portions.

A now standard law of network theory that states that the value of any given network is proportional to the square of the number of connected users of that system. In other words, more users increase the value of a network at an exponential rate.

The degree to which a system's components may be separated and recombined, often with the benefit of flexibility and variety in use.

The paradox that people are held morally responsible for outcomes significantly shaped by factors beyond their control — even though most ethical frameworks assume moral judgment should depend only on what a person freely chose.

The observation that if something can go wrong, it eventually will. A reminder to design for failure and plan for the unexpected rather than assuming the best case.

A state in a strategic game where no player can improve their outcome by changing strategy alone. Everyone is doing their best given what everyone else is doing — even if the collective result isn't optimal.

The effect of the value of a product or service where it is dependent on the number of others using it.

The phenomenon that occurs when at some stage of development, certain ideas become so universally accepted and commonly used that their contributors are no longer cited.

A design principle where components of a system are independent, so changing one doesn't affect the others. Orthogonal systems are easier to understand, test, and modify.

Building something far more complex or robust than the situation requires. The extra effort adds cost and rigidity without meaningful benefit.

Understanding the relationship between components of complex systems where interactions between the components occur at different "paces" of evolution. The categories are nature, culture, governance, infrastructure, commerce, and fashion.

A fundamental change in the basic concepts and experimental practices of a scientific discipline.

A state of allocation of resources in which it is impossible to make any one individual better off without making at least one individual worse off.

A theory suggesting that trends in culture, politics, etc., tend to swing back and forth between opposite extremes, much like the pendulum of a lock.

A process that occurs in a feedback loop in which the effects of a small disturbance on a system include an increase in the magnitude of the perturbation.

X happened, then Y happened; therefore, X caused Y — an example of a time sequence implying causation.

The notion that a component of a system should behave in a way that most users will expect it to behave; the behavior should not astonish or surprise users.

People and systems naturally choose the path of least resistance and cease once acceptable results are found or achieved — holds regardless of experience or proficiency of the person or system.

The confusion of association with causation, either by inappropriately deducing (or rejecting) causation or a broader failure to properly investigate the cause of an observed effect.

A flaw in system design where the outcome depends on the timing or sequence of uncontrollable events. When two processes collide, unpredictable things happen.

Restraint is where something holds itself back from doing something, where constraint is a limitation that is built into one’s environment.

The phenomena where people wrongly assume that something that works at one size will also work at another size.

The process of estimating and considering the implications of impacts of a first-order effect (initial effects).

A prediction that directly or indirectly causes itself to become true, by the very terms of the prophecy itself, due to positive feedback between belief and behavior.

Software engineering principle that emphasizes the importance of dividing a system or application into distinct and modular components, with each component addressing a specific concern or aspect of the system.

A code smell where a single change requires making many small edits scattered across multiple files or modules. A sign of poor separation of concerns.

Software design principle that states that a class or module should have only one reason to change, and should be responsible for only one aspect or feature of the system it represents.

The emergence of organized patterns and structures without any central planner or authority. Markets, languages, and social norms all arise this way.

A folk story in which hungry strangers convince the people of a town to each share a small amount of their food in order to make a meal that everyone enjoys (and whereby the inedible stone can be removed when the neighboring ingredients are sufficient to make an actual soup), and exists as a moral regarding the value of sharing.

A cyclic structure that goes through several levels in a hierarchical system, and arises when, by moving only upwards or downwards through the system, one finds oneself back where one started.

A classic economic model of price determination in a market. In a competitive market, the unit price for a particular good or other traded item such as labor or financial assets, will vary until it settles at a point where the quantity demanded will equal the quantity supplied, resulting in an economic equilibrium for price and quantity transacted.

An approach to analysis that focuses on how a system's parts interrelate and work together over time, rather than reducing them to isolated components.

A safety system that uses physical locks and keys to enforce a fixed sequence of operations on industrial equipment, ensuring each step is completed before the next can begin.

An expression of the problem of needing something to explain something to explain something, etc., where the expression alludes to the mythological idea of a World Turtle that supports the earth on its back, and then the question being asked of what supports \*that\* turtle.

The things that happen as a result of some action, which were not necessarily anticipated — which could possibly be an unexpected benefit, an unexpected drawback, or even a backfire against the original action.

The term given to a component in a system that is most likely to fail, regardless of the strength of adjacent components.

The consequence of moving an element from one set to another set which raises the average values of both sets.

Mistaking the effect for the cause — assuming that because two things correlate, the direction of causation is the opposite of what it actually is.