Pratimus

Pratimus is a term used in theoretical modeling to denote the most basic unit of cooperative action within a specified system. In this context, a pratimus represents a single, indivisible step that an agent can perform that influences other agents or outcomes, and it cannot be decomposed into smaller cooperative subactions under the model's rules. The concept is abstract and not tied to a real organism or physical object.

Origin and usage: The term was coined in early 21st-century discussions of agent-based modeling and collective behavior, with varying spellings and definitions in different research communities. It is not a standard term across disciplines, and definitions may differ by model.

Formal properties: A pratimus usually has a defined precondition, an action, and an effect on the environment or on other agents. In simulations, pratimus actions may be serialized or staged; they can be deterministic or stochastic. Studying pratimi can help analyze how large-scale cooperation emerges from simple actions, and how system parameters such as payoff structure or visibility influence outcomes.

Criticism and alternatives: Critics argue that “pratimus” is a heuristic that depends heavily on the chosen model granularity and may obscure underlying mechanisms. Alternatives include more granular micro-actions, or aggregated macro-actions.

In culture: The term appears rarely outside academic contexts, occasionally used in science fiction to illustrate minimal units of social action, without implying real entities. This article describes pratimus as a modeling construct rather than a real-world object or organism.