Environment
Everything outside the system boundary that interacts with it — the sources providing inputs, the sinks receiving outputs, and the context in which the system operates.
Formal Definitions
Mobus & Kalton (2015):
“Every system of interest (SOI) is embedded in a larger system, the supra-system. The environment contains all of the sources of inputs (matter, energy, and messages) and the sinks for outputs. It also contains all of the channels (or fields) through which flows occur. The entities of the environment connect directly with the boundary of the SOI.”
(Principles of Systems Science, Section 3.5)
Environment appears at Level -1 in the systems ontology, alongside SUPRA-SYSTEM, CONTEXT, and MEANING.
(Section 3.5, Fig. 3.13)
Bunge (1979):
“The A-environment of σ at time t is the set of all things of kind A, not components of σ, that act or are acted on by components of σ at t: E_A(σ, t) = {x ∈ A | x ∉ C_A(σ, t) & (∃y)(y ∈ C_A(σ, t) & (x ⊳ y ∨ y ⊳ x))}”
(A World of Systems, Chapter 1, Definition 1.2)
The symbol ⊳ denotes “acts upon.”
Synthesis
Bunge’s action-based definition is precise: environment consists only of things that actually interact with the system, not merely “everything outside.” Mobus operationalizes this through source/sink/channel structure while adding temporal context. Both agree environment is relationally defined — it changes as the system’s interactions change.
Key Insight
The environment is not passive backdrop — it co-constitutes the system. A system’s identity is partly defined by what it exchanges with its environment.
Explore Further
- Unit of survival is organism-in-environment — Bateson on irreducible coupling
- Search internal sources before blaming environment — Bunge’s methodological caution
- Thermodynamics and system-environment exchange — Fundamental pattern of interaction
- Adaptive systems in changing environments — Stability through flexibility