If a person's head moves, she may or may not have moved her head, and, if she did move it, she may have actively performed the movement of her head or merely, by doing something else, caused a passive movement. And, if she performed the movement, she might have done so intentionally or not. This short array of contrasts (and others like them) has motivated questions about the nature, variety, and identity of action. Beyond the matter of her moving, when (...) the person moves her head, she may be indicating agreement or shaking an insect off her ear. Should we think of the consequences, conventional or causal, of physical behavior as constituents of an action distinct from but ‘generated by’ the movement? Or should we think that there is a single action describable in a host of ways? Also, actions, in even the most minimal sense, seem to be essentially ‘active’. But, how can we explain what this property amounts to and defend our wavering intuitions about which events fall in the category of the ‘active’ and which do not? (shrink)