action theory the study of the ontological structure of human action, the process by which it originates, and the ways in which it is explained. Most human actions are acts of commission: they constitute a class of events in which a subject (the agent) brings about some change or changes. Thus, in moving one’s finger, one brings it about that one’s finger moves. When the change brought about is an ongoing process (e.g., the continuing appearance of words on a page), the behavior is called an activity (writing). An action of omission occurs when an agent refrains from performing an action of commission. Since actions of commission are events, the question of their ontology is in part a matter of the general ontology of change. An important issue here is whether what occurs when an action is performed should be viewed as abstract or concrete. On the first approach, actions are understood either as proposition-like entities (e.g., Booth’s moving a finger), or as a species of universal – namely, an act-type (moving a finger). What ‘occurred’ when Booth moved his finger in Ford’s Theater on April 14, 1865, is held to be the abstract entity in question, and the entity is viewed as repeatable: that is, precisely the same entity is held to have occurred on every other occasion of Booth’s moving his finger. When actions are viewed as concrete, on the other hand, Booth’s moving his finger in Ford’s Theater is understood to be a non-repeatable particular, and the movement of the finger counts as an acttoken, which instantiates the corresponding acttype. Concrete actions are time-bound: each belongs to a single behavioral episode, and other instantiations of the same act-type count as distinct events.
A second important ontological issue concerns the fact that by moving his finger, Booth also fired a gun, and killed Lincoln. It is common for more than one thing to be accomplished in a single exercise of agency, and how such doings are related is a matter of debate. If actions are understood as abstract entities, the answer is essentially foregone: there must be as many different actions on Booth’s part as there are types exemplified. But if actions are viewed as particulars the same token can count as an instance of more than one type, and identity claims become possible. Here there is disagreement. Fine-grained theories of act individuation tend to confine identity claims to actions that differ only in ways describable through different modifications of the same main verb – e.g., where Placido both sings and sings loudly. Otherwise, different types are held to require different tokens: Booth’s action of moving his finger is held to have generated or given rise to distinct actions of firing the gun and killing Lincoln, by virtue of having had as causal consequences the gun’s discharge and Lincoln’s death. The opposite, coarse-grained theory, however, views these causal relations as grounds for claiming Booth’s acts were precisely identical. On this view, for Booth to kill Lincoln was simply for him to do something that caused Lincoln’s death – which was in fact nothing more than to move his finger – and similarly for his firing the gun. There is also a compromise account, on which Booth’s actions are related as part to whole, each consisting in a longer segment of the causal chain that terminates with Lincoln’s death. The action of killing Lincoln consisted, on this view, in the entire sequence; but that of firing the gun terminated with the gun’s discharge, and that of moving the finger with the finger’s motion.
When, as in Booth’s case, more than one thing is accomplished in a single exercise of agency, some are done by doing others. But if all actions were performed by performing others, an infinite regress would result. There must, then, be a class of basic actions – i.e., actions fundamental to the performance of all others, but not themselves done by doing something else. There is disagreement, however, on which actions are basic. Some theories treat bodily movements, such as Booth’s moving his finger, as basic. Others point out that it is possible to engage in action but to accomplish less than a bodily movement, as when one tries to move a limb that is restrained or paralyzed, and fails. According to these accounts, bodily actions arise out of a still more basic mental activity, usually called volition or willing, which is held to constitute the standard means for performing all overt actions. The question of how bodily actions originate is closely associated with that of what distinguishes them from involuntary and reflex bodily events, as well as from events in the inanimate world. There is general agreement that the crucial difference concerns the mental states that attend action, and in particular the fact that voluntary actions typically arise out of states of intending on the part of the agent. But the nature of the relation is difficult, and there is the complicating factor that intention is sometimes held to reduce to other mental states, such as the agent’s desires and beliefs. That issue aside, it would appear that unintentional actions arise out of more basic actions that are intentional, as when one unintentionally breaks a shoelace by intentionally tugging on it. But how intention is first translated into action is much more problematic, especially when bodily movements are viewed as basic actions. One cannot, e.g., count Booth’s moving his finger as an intentional action simply because he intended to do so, or even on the ground (if it is true) that his intention caused his finger to move. The latter might have occurred through a strictly autonomic response had Booth been nervous enough, and then the moving of the finger would not have counted as an action at all, much less as intentional. Avoiding such ‘wayward causal chains’ requires accounting for the agent’s voluntary control over what occurs in genuinely intentional action – a difficult task when bodily actions are held to be basic. Volitional accounts have greater success here, since they can hold that movements are intentional only when the agent’s intention is executed through volitional activity. But they must sidestep another threatened regress: if we call for an activity of willing to explain why Booth’s moving his finger counts as intentional action, we cannot do the same for willing itself. Yet on most accounts volition does have the characteristics of intentional behavior. Volitional theories of action must, then, provide an alternative account of how mental activity can be intentional. Actions are explained by invoking the agent’s reasons for performing them. Characteristically, a reason may be understood to consist in a positive attitude of the agent toward one or another outcome, and a belief to the effect that the outcome may be achieved by performing the action in question. Thus Emily might spend the summer in France out of a desire to learn French, and a belief that spending time in France is the best way to do so. Disputed questions about reasons include how confident the agent must be that the action selected will in fact lead to the envisioned outcome, and whether obligation represents a source of motivation that can operate independently of the agent’s desires.
Frequently, more than one course of action is available to an agent. Deliberation is the process of searching out and weighing the reasons for and against such alternatives. When successfully concluded, deliberation usually issues in a decision, by which an intention to undertake one of the contemplated actions is formed. The intention is then carried out when the time for action comes. Much debate has centered on the question of how reasons are related to decisions and actions. As with intention, an agent’s simply having a reason is not enough for the reason to explain her behavior: her desire to learn French notwithstanding, Emily might have gone to France simply because she was transferred there. Only when an agent does something for a reason does the reason explain what is done. It is frequently claimed that this bespeaks a causal relation between the agent’s strongest reason and her decision or action. This, however, suggests a determinist stance on the free will problem, leading some philosophers to balk. An alternative is to treat reason explanations as teleological explanations, wherein an action is held to be reasonable or justified in virtue of the goals toward which it was directed. But positions that treat reason explanations as non-causal require an alternative account of what it is to decide or act for one reason rather than another.
See also EVENT, FREE WILL PROBLEM , INTENTION , PRACTICAL REASONING , VOLI — TIO. H.J.M.