What Levers are there for the Behavior to Pull?

My intuition here imagines a small man inside the pill-box computing and interacting with the outside world by pulling levers. His behavior may be inscrutable but for some purposes we will be broadly trusted to act in certain ways that we prescribe.

He can send a message thus:

There are occasions when behavior gets the opportunity to process a message which was addressed by the capability to the object whose behavior we consider. The nature of those opportunities is one of the real sources of variation.