Complexity – a glossary


  • Agent
    Something that takes part in an interaction & is subsequently changed; e.g. a person, a society, a plant, a student, the teacher
  • Attractor
    Where a system tends to end up over time, if you plot successive points on its trajectory, which is often cyclical; e.g. a valley into which rain water flows after following many paths on its way down, or a wash basin.
  • Boundaries
    A demarcation or barrier of sorts that allows exchange between a system and its environment. These are permeable to outside input; e.g. a cell membrane, cultural rules.
  • Chaos
    The apparent absence of order in a system which is actually deterministic with hidden order. E.g. weather systems are often chaotic yet contain predictability
  • Chaotics
    A blend of the theories and ideas about chaos and complexity.
  • Complex Adaptive System (CAS)
    A non linear system with the potential for self-organisation in a permeable environment which at times is far from equilibrium. Evolution is based on its history. E.g. the immune system, stock markets, the human nervous system
  • Deterministic systems
    A linear system in which later states are clearly determined by previous ones. In contrast to stochastic systems where future behaviour is independent of previous states.
  • Dynamic systems
    A complex interactive system evolving over time through multiple modes of behaviour & following certain rules; e.g. the cardio vascular system.
  • Emergence
    The arising of new unexpected structures, patterns or processes in a self organising CAS. e.g a jazz group playing live, learning.
  • Equilibrium
    A system that tends to remain at status quo, unchanged. E.g. a traditional school?
  • Edge of chaos; far from equilibrium.
    The conditions that lead to self-organising. E.g. a new set of institutional rules, cognition
  • Fractal
    This is a geometrical shape that is irregular all over yet is “self-similar” in that the shape looks the same from all distances, near or far. A portion is equivalent to the whole system. E.g the British coastline, a cauliflower
  • Linear system
  • A system in which the variables plot a straight line. Predictable changes occur and a small change has a small effect. E.g thermostat
  • Non-linear system
    Variables are represented by curvilinear patterns, and feedback loops have unpredictable effects, yet can be replicable. E.g Starling’s curve for the heart, weather systems, presidential elections
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