Agents

While Goodwin implies that all agents exist in order to effect changes of some sort in their environment, he never actually states this.

A housebrick could be an agent within Goodwin's formalism: The surfaces of the brick are its effectors. Its task is to not compress, that is, its task is to hold other objects apart (presumably other bricks). Its sensors are non-existent - sufficient, but degenerate. It is reflexive in that it responds to the "stimulus" of pressure by resisting collapse, though this is a somewhat long bow! The brick could even be seen as a deliberative agent, with a degenerate internal model of the world, though it seems (slightly) more satisfying to consider the brick a reflexive agent.

The properties "successful" and to a lesser extent "capable" provide admirably well for a sliding scale; Goodwin in fact wishes his formalisation to provide a basis for comparing the performance of agents performing the same tasks in the same environment. A sliding scale needs extremes, and perhaps the brick is one extreme. The only escape seems to be the tenuous requirement that "success means total success" - since the brick performs its task indefinitely, we have no way of knowing that it hasn't succeeded unless it actually eventually succumbs to pressure and collapses (or is removed from duty). Until then we can only say "so far, so good...".

This same comment would appear to apply to any task falling into the class of tasks Goodwin refers to as "tasks of maintenance", that is, tasks where the agent must "maintain some condition in the environment". The example Goodwin gives is an agent controlling room temperature. This could be avoided by modifying the formalisation so that such tasks are defined as sequences of tasks, each to be achieved within a set period. However, it seems to me that allowing a housebrick status as an agent, even as a degenerate case, is a weakness in this formalism.

There seems to be some ambiguity in Goodwin's formalism regarding the place of humans. Firstly, theological arguments aside, it does not seem obvious that humans are created to accomplish specific tasks (Goodwin's fundamental definition). Secondly, Goodwin specifically limits his model to "simple deliberative agents" which do not learn. That is, they can alter the state of their internal model, but not the model itself. However in defining a non-deterministic environment, Goodwin postulates agents with free will (presumably humans) as part of that environment.

On the whole I suspect that Goodwin does not intend his formalism to apply to humans, though humans are part of the environment within which he expects agents to operate. The ambiguity arises from a statement of purpose ("...created to perform...") without any statement of the source of that purpose.