Structure-determined systems: systems whose changes depend on their structure, not on external agents. The environment triggers change. The structure determines what change occurs.
A structure determined system is one whose behavior follows from its structure, not from external specification. Input acts as a trigger. Structure determines output.
Compare two systems. Mechanical toy: push button, arm raises. The input specifies the output. Input output relationship designed externally.
Living organism: push organism, it might flee, fight, ignore, or investigate. Same input. Multiple possible outputs. The organism’s structure determines which output occurs based on current state and history.
Structure determined doesn’t mean deterministic in practice. The observer cannot know the complete structure. Cannot predict exact output. But the system’s behavior is determined by structure, not by external instruction.
All autopoietic systems are structure determined. Their autopoietic organization requires organizational closure, which means structure determines state changes, not environment.
The environment can destroy structure determined systems. Overwhelming perturbation exceeds structural capacity. But the environment cannot specify how the system operates within viable range. Structure does that.
Structure-determination explains apparent unpredictability of living systems.
From outside: organism behavior seems inconsistent, unpredictable, possibly random. Same stimulus, different response. Confusing if expecting input output specification.
From inside: completely determined by structure. Response follows necessarily from current structural state and perturbation. Predictable in principle if structure were completely known.
The gap between these perspectives creates the appearance of agency, choice, spontaneity. Not because living systems violate physical law. Because they’re structure determined and observers cannot access complete structural state.
Example: Training animals. Trainer provides stimulus. Animal’s structure determines its response. Effective training means creating coupling where the animal’s structure determined responses align with the trainer’s goals. Not forcing behavior through instruction. Triggering behavior through perturbations that the animal’s structure transforms into desired actions.
Failed training often comes from treating animals as instruction following machines. Giving commands and expecting obedience. But commands are perturbations. Responses are structure-determined. Disconnecting between expected instruction-following and actual structure-determined operation creates failure.
If living systems are structure determined:
Behavior reflects structure, not environment alone. Understanding why a system behaves as it does requires knowing its structure, not just observing its inputs.
Change requires structural change. To alter behavior patterns, alter structure through perturbations that trigger the desired structural modifications. Cannot change behavior through instruction alone.
The same environment produces different behaviors in different structures. Identical environmental conditions couple with different structural configurations to produce different operational outcomes.
Recognition: When a system doesn’t respond as expected to environmental inputs, the issue isn’t environmental, it’s structural. The system is operating exactly as its structure determines. Desired changes require structural modifications through appropriate perturbations, not louder or more frequent environmental signals.
Structure determined systems: behavior follows from structure interacting with the environment. Environment triggers. Structure specifies.
All living systems operate this way. Autonomy through structural determination.
@ Lee Greene