 A key point to grasp in many of the issues raised by Anomalous Monism is that there is an important distinction between action and behavior. According to Davidson, action is intentionally described behavior—the moving of a hand through space in a certain way may, but need not, be an action of waving or swatting or any action at all. It may simply be mere bodily behavior—as happens as the result of a muscle twitch or a strong gust of wind. The behavior must be caused by an agent’s beliefs and desires in order to be action. However, while this is necessary for action, it is not, according to Davidson, sufficient. The behavior must be caused in the right way by the beliefs and desires. Davidson notes the possibility of cases where an agent’s beliefs and desires cause behavior which is not rationalized by those states, and thus not action. A mountain climber might become so unnerved by his desire to rid himself of an annoying second climber sharing his rope and belief that jiggling the rope is a means for doing so that he unintentionally jiggles the rope, leading to the loss of the second climber. This is not an action—it is mere behavior that happens to him, no different than if caused by a muscle twitch or gust of wind. It is caused in the wrong way—a “deviant causal chain”—by the belief and desire, and so is not an action. Davidson is skeptical about the possibility of cashing out what it means to be caused in the right way (Davidson 1973b, 78–9), for reasons relating to mental anomalism (Davidson 1973b, 80; see  4  for explicit discussion). The key point for now is that because Davidson rejects the possibility of analyzing action in terms of behavior caused in a particular way by reasons, the point made by the ‘because’ argument cannot be used to establish that mental events cause physical events. It does not follow from the fact that reasons must cause actions in order to explain them that reasons must cause behavior or (the interaction principle) that reasons do cause behavior. It does not entail that actions are physical behavior.