  However, all of this discussion suppresses a basic metaphysical mystery. In the preceding two paragraphs, it has been proposed that the neural activity, the muscle contractions, and the overt hand movements may all be actions, while the switch's flipping on, the light's coming on, and the burglar's becoming alert are simply happenings outside the agent, the mere effects of the agent's overt action. As we have seen, there is plenty of disagreement about where basic agency starts and stops, whether within the agent's body or somewhere on its surface. There is less disagreement that the effects of bodily movement beyond the body, e.g., the switch's flipping on, the onset of illumination in the room, and so on, are not, by themselves at least, purposeful actions. Still, what could conceivably rationalize any set of discriminations between action and non-action as one traces along the pertinent complex causal chains from the initial mind or brain activity, through the bodily behavior, to the occurrences produced in the agent's wider environment?