agent definitions — complex systems

published: October 27, 2025

overview

complex-systems scholarship treats agents as rule-based components whose local interactions yield emergent macro patterns. agent-based modeling (abm), adaptive systems theory, and thermodynamic approaches all appear in this cluster.

signature traits

  • local rules, global effects: agents follow simple rules; collective behavior emerges from interaction networks (holland 1995, epstein & axtell 1996).
  • adaptation: agents evolve strategies via learning, reproduction, or selection.
  • environment coupling: agents are situated in explicit environments with resource flows or state variables.

illustrative definitions

  • 1995 — john holland, hidden order: complex adaptive systems comprise many interacting agents that learn and co-evolve.
  • 1996 — epstein & axtell, growing artificial societies: defines abm agents as autonomous heterogeneous individuals driving emergent social dynamics.
  • 2000 — stuart kauffman, investigations: describes autonomous agents capable of reproduction and thermodynamic work cycles.

relation to other dimensions

  • autonomy spectrum: varies from rule-following automata (moderate autonomy) to self-maintaining systems (high autonomy).
  • entity frames: straddle hybrid and machine frames; agents may represent people, firms, or synthetic organisms.
  • goal dynamics: often focuses on adaptation rather than explicit negotiation; objectives emerge through evolution or feedback.
  • persistence & embodiment: many models assume persistent agents; some, like kauffman, insist on physical embodiment and metabolism.

open questions

  • how can insights from abm about emergent coordination inform multi-agent llm orchestration?
  • do thermodynamic definitions belong in the same comparative space as purely digital abm agents?
  • what metrics best capture when rule-based agents transition from delegate behavior to self-maintaining systems?
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