Internal Model
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A living system is created to function within a specific set of environmental conditions. Its governance mechanism creates an internal model of this particular environment, and its action scenario capabilities are configured for interaction with that environment. The internal model provides the frame of reference through which the living system comprehends the world.


Environment Sets the Stage
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In this discussion, "environment" refers to the set of physical conditions within which a particular living system exists and carries out its life functions. The living system evolved over time to sustain life in that particular environment. Its physical structure is configured to interact with that environment, and its sensory systems have been formed to help guide interactions with that environment.
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The living system's governance mechanism is designed to orchestrate its life function actions within its particular environment. To carry out this control requirement, the governance structure embodies an internal model of both the living system's external environment and its own internal structure. Through evolution, this model has been continuously tailored to include just those external and internal aspects of its existence that are necessary for the living system to interact with its world, maintain homeostasis and survive.

Internal Model of the World
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The internal model is an abstract representation of everything the living system needs to know about the world and itself. For a given kind of living system, the model's complexity matches that of its functional capabilities and the extent to which it must interact with its environment and adjust its internal conditions. Simple cells have a relatively simple model, while complex organisms have a more complex model.
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 An Internal Model is a Living System's Framework for Action. 
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In complex living systems, the model includes a history of sensed external situations, internal conditions, past actions and results, and current status. This model provides the basis for initiation and control of current and future actions by the living system.

The Model is Based on Action Scenarios
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In all but the simplest living systems, the structure of the model is based on a complex array of action-perception-action scenarios, rather than static data. These scenarios relate to the continuous and ongoing stimulus-response nature of life functions within a dynamic environment.
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 A Scenario Embodies both Sensory Memory and Action Capability. 
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Scenarios are records of sequences of sensed patterns, feelings and actions, at various levels of detail. Note that sensed patterns include pain, pleasure and emotional feelings that indicate whether an action produced "good" or "bad" results. Within complex living systems, there is always a continuous array of scenarios in process. Some scenarios are immediately reactive, some purposeful, and some autonomic.
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Scenarios can be viewed either individually, as networks, or as complex dynamic hierarchies. A complex scenario structure can include mixed types of detailed scenarios. At any given moment in time, scenarios may be disjointed units or structurally integrated, depending on requirements of the situation and conditions. A threatening situation may invoke a high degree of scenario integration, leading to quick, orchestrated action for fight or flight. In a stable situation, multiple disjointed scenarios may simultaneously attend to individual life function needs.

Basic Kinds of Scenario
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The basic architecture of an internal model is the same for all living systems, but the complexity varies widely across the three levels of living system. To illustrate this range of complexity, scenarios can be divided into four types, listed in order of increasing complexity:
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Simple-Reaction Scenario: sense-react, sense-react, . . .
Need-Seeking Scenario: search-sense-adjust, search-sense-adjust, . . .
Learning Scenario: react-sense-remember, react-sense-remember, . . .
Goal-Driven Scenario: act-sense-compensate, act-sense-compensate, . . .
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Living System Scenario Capabilities
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A living system may employ more than one type of scenario. In general, the simpler the living system, the simpler the scenarios that it uses. This table shows examples of how scenarios are applied by living systems of different complexities and capabilities, starting with a simple cell and ending with a complex superorganism:
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 Type of Living System Example  Highest Scenario Capability 
 Simple Cell:  Prokaryote  simple-reaction
 Complex Cell:  Eukaryote   need-seeking 
 Simple Organism: Ant  need-seeking
 Complex Organism: Human learning and goal-driven
 Simple Superorganism:  Ant Colony  need-seeking and learning
 Complex Superorganism:  Nation-State learning and goal-driven



Scenario Control Units shows how governance keeps the internal model scenarios on track through its control unit structure.


©1995-2012 Ackley Associates    Last revised: 7/16/11
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