The good enough calculi of evolving control systems: evolution is not engineering.

In evolved aggregates of accidentally invented elements, retained when statistically good enough to identify limitations of antecedent systems, survival value might favor operators incorporating aspects of, while not identical with, feedback, feedforward, state varible, and "homeostatic" control. Generally, simple organizational increments should predominate. After invention, an internal controller with readily modifiable rules could facilitate evolution of compound inventions, but criteria controlling rule changes would be only indirectly (probably imperfectly) survival referent. Consequent to combination of independent invention with indirect criteria and statistical acceptance, evolved control logic could be: both redundant and incomplete; good enough with malefic aspects; built of loosely linked or autonomous sublogics; and a source of good enough solutions from incomplete information. The partially explicit rules are defined more by rejections than by ratifications. Study of the result based on formal logic, engineering conventions, and familiar coordinate systems could conceive illegitimate illusions of understanding.