State
The configuration of a system at a specific moment — the values of its variables and relationships between components right now.
Formal Definitions
Mobus & Kalton (2015):
“Imagine taking a reading on every flow (connection) and every reservoir in a system and all of its subsystems every Δt instance. The state σ_i of the system where i is the index of the set of possible states S.”
(Principles of Systems Science, Section 4.3)
State as a vector of measurements:
“Let H at time t be defined as a set of measures (a list of variables in the system): H_t = [v_1, v_2, v_3, …, v_n]_t”
(Section 4.3)
Bunge (1979):
“A thing is an aggregate iff its state space equals the union of the state spaces of its components, otherwise it’s a system.”
(A World of Systems, p. 22, Chapter 1)
This provides a mathematical criterion: genuine systems have emergent state spaces — states the whole can occupy that no component alone can.
Synthesis
Mobus defines state as instantaneous measurements of all system variables, creating a point in state space. Bunge uses state space mathematically to distinguish true systems from mere aggregates — systems have emergent state dimensions. Both use state space formalism but for different analytical purposes: Mobus for modeling, Bunge for ontological classification.
Key Insight
State is the bridge between structure and dynamics. Structure constrains what states are possible; dynamics describe how states change. The set of all reachable states defines the system’s behavioral repertoire.
Explore Further
- Aggregates vs systems — State space as the criterion
- State space clarified — Concrete examples from Bunge
- States gained or lost — Dynamic state repertoire
Related Concepts
- System — what has state
- Flow — causes state transitions
- Adaptation — changes which states are possible