The action of opening a door consists in the agent's voluntarily exerting parts of her body – her arm and hand, let us suppose – in such a way that that action (the voluntary exertion of the body) causes the door to open. It is possible, in principle, to open a door without using any voluntary exertion to do so. Conceivably, a person's brain could be so wired to a door that merely by mentally saying “Open sesame!”, and without any exertion of her body, she could cause the door to open. There are ways in which one can act on or with one's body without engaging in any voluntary exertion. (For example, sexual arousal can be produced by forming appropriate mental images.) And our lives are filled with mental actions – mentally saying things, forming mental images, and the like – that, though they may affect the body, do not in themselves and in virtue of their very notion include any bodily event, whether voluntary exertion or other. But it is nonetheless true that actions done by voluntarily exerting the body, together with voluntary exertions themselves, comprise most of the actions that we have occasion to consider explicitly. Our voluntary exertions of our bodies are a central and especially important sort of action. We must understand what they are if we are to understand most sorts of actions we talk about.

Is freedom of the will compatible with determinism? I think not, and I would like to explain why.

First, let me explain what I take this venerable question to mean. By freedom of the will is meant freedom of action. I have freedom of action at a given moment if more than one alternative action is then open to me. Two or more actions are alternatives if it is logically impossible for me to do more than one of them at the same time. Two or more alternatives are open to me at a given moment if which of them I do next is entirely up to my choice at that moment: Nothing that exists up to that moment stands in the way of my doing next any one of the alternatives.

OUR IMPRESSION OF FREEDOM DOES NOT MAKE US FREE

We all continually have the impression that our wills are thus free. For example, at most moments while I am sitting and talking or listening to someone, I have the impression that there are several alternative things I could do next with my right hand: gesture with it, scratch my head with it, put it on my lap, put it in my pocket, and so on. For each of these alternatives, it seems to me that nothing at all up to that moment stands in the way of my making it the next thing I do with my right hand; it seems to me that what has happened hitherto, the situation at that moment, leaves each of those alternatives still open to me to perform.

The philosophy of action deals with the notion of action that applies only to beings who have wills. (The words action and act are, of course, applied to other sorts of entities – we speak of the action of the acid on the metal and of how the pistons act to move the drive shaft – but what action and act mean in such applications is not a concern here.) We take ourselves, people, to be the paradigms of enwilled agents. That we are beings who act is a fundamental fact about us. It is as important as the fact that we are cognizers, beings who know and believe. (These two aspects are, of course, thoroughly interconnected: The knowledge and beliefs we have and those we want influence our actions, and our actions influence the beliefs we come to have.) Yet, though philosophers in the Western tradition from Socrates on have had much to say about action, it is only in the last three decades or so that the theory of action has come to be thought of as a distinct branch of philosophy, on a par with the theory of knowledge. This may be because there was a tendency to think of action as a subconcern of philosophizing about rationality and morality. And indeed, very important questions about action arise there, such questions as what it is to choose one's actions rationally and what makes it the case that a person is morally responsible for an action.

What is it for a person to act? It is easy to give examples. I act when I voluntarily move my limbs, when I open a door, when I speak or write, press keys on the keyboard, slice a melon, or throw a ball, when I mentally say a word or mentally rotate a visual image. But not all events or states of which a person is the subject are actions. There are, for instance, perceptions, sensations, desires, beliefs, feelings, unbidden thoughts, faintings, sneezings, tremblings, reflex actions, and states of passivity. What distinguishes actions from these other sorts of things? What is the mark of action? Answering this question is not so easy.

REFORMULATING THE QUESTION

It is useful to have a standard way of referring (in English) to particular personal events and states, including actions. A suitable form of a singular noun phrase can be derived from any indicative active sentence that predicates of a person some event or state simply by changing the subject to its possessive form and changing the verb to the present participle. Thus the sentences “Sue suffered during the race” and “Tom started the engine five minutes ago” become, respectively, the singular noun phrases “Sue's suffering during the race” and “Tom's starting the engine five minutes ago”.

To be the canonical designator I want, such a noun phrase must pick out a particular personal event or state uniquely.

The preceding chapter argued for incompatibilism. In this chapter, I want to rebut two arguments against incompatibilism that have been put forward from time to time. Incompatibilism can be defined this way: Any free action must be an undetermined event. A free action is one such that, until the time of its occurrence, the agent had it open to her to perform some alternative action (or to be inactive) instead. An undetermined event is one that was not nomically necessitated by the antecedent state of the world. (Hence, a determined event is one that was nomically necessitated by its antecedents.) An event was nomically necessitated by the antecedent state of the world if and only if the antecedent state together with the laws of nature determined that that event, rather than some alternative, would occur.

The most widely supported argument against incompatibilism, to which I will give by far the larger response, combines the consideration that a free action can be influenced by the agent's intentions, desires, and beliefs – can have an explanation in terms of reasons for which the agent did it – with the assumption that only a determined event can have such an explanation. My response to this argument will be to counter the assumption by offering an adeterministic or anomic account of such explanations. The other argument does not assume that reasons explanations are deterministic (nor does it assume the contradictory), but simply claims that where we have an undetermined action we do not have an agent in control of (determining) what her action is to be: We do not have an action that the agent chooses, freely or otherwise.

Some actions are intentional and some are not. For example, Sarah's action of stepping on Susy's toes was not intentional, but Susy's subsequent action of stepping on Sarah's toes was intentional. Whether an action was intentional or not can be important. It can make a difference in our attitude toward the action and in our evaluation of it. What makes an action intentional? Let me rephrase the question. Given that ‘S's V-ing at t» is a canonical designator of an action, what is necessary and sufficient for the truth of ‘S's V-ing at t was intentional (SV-ed at t intentionally)»?

RELATIVITY TO DESCRIPTION

The same action can be intentional under one designator of it and not intentional under another. For example, ‘S's pirouetting at t» and ‘S's pirouetting clumsily at t» designate the same action. But it may nevertheless be correct to say that ‘S's pirouetting was intentional but S's pirouetting clumsily was not intentional.

Some canonical action-designators imply that the action they designate was intentional (at least under that designation), for example, ‘S's calling for help at t», ‘S's looking around her at t», ‘S's groping for the light switch at t», ‘S's deciding to run away at t», ‘S's mentally saying “nonsense” at t», or any of the form ‘S's intentionally V-ing at t». Other designators imply that the designated action was not intentional (at least under that designation), for example, any of the form ‘S's unintentionally V-ing at t».

Our definition of an action in Chapter 1 tells us how to select from among canonical personal-event-designators those that designate actions. But to know what makes an action-designator is not yet to have a complete understanding of what makes an action. For canonical action-designators are not correlated one to one with actions. Distinct designators do not always designate distinct actions. For example, it is natural to think that although «S's willing to exert force with her hand at t» and «S's raising her hand at t» designate distinct actions, «S's raising her hand at t» and «S's slowly raising her right hand at t» designate the same action (given that each of these designators is canonical and thus uniquely picks out a single action). But our criterion for picking out action-designators does not tell us what guides such a judgment. This chapter takes up the task of developing a criterion for deciding when distinct (canonical) action-designators designate distinct actions.

We need to be concerned here only with designators in which the type of the action designated is made fully explicit. Consider a designator of the form «S's doing this morning the same thing she did yesterday that R complained about», one that uniquely picks out a particular action. It picks it out as being of a certain type (the type S did yesterday that R complained about), but it does not, just in virtue of its content, tell us what that type is.