What Is Philosophy of Action?

Direct Answer

Philosophy of action is the philosophical study of what it is to act — the nature of intentional action, agency, and the relationship between reasons and causes. It asks what distinguishes an action from a mere bodily movement, what makes an action intentional, how agents exercise control over their behavior, and how the reasons for which we act relate to the causal processes that produce our movements. When you raise your hand to ask a question, that is an action. When your arm rises because someone pushed it, that is not an action but something that happens to you. Philosophy of action asks what makes the difference.

The central questions of the field are deceptively simple. What is an action? When is an action intentional? What is it to do something for a reason? How do reasons relate to causes? What is agency — the capacity to originate action? These questions matter because they lie at the intersection of metaphysics, epistemology, ethics, and the philosophy of mind. To understand what it is to act is to understand what it is to be an agent — a being who does things for reasons, who is responsible for what they do, and whose actions shape the world and themselves.

The foundational insight, going back to Aristotle, is that action is not just behavior — it is behavior animated by purpose and understanding. A person who waves their hand accidentally has not performed the same action as a person who waves their hand to signal a friend, even though the bodily movement is the same. The difference lies in the intention, the reason, and the agent's understanding of what they are doing. Philosophy of action seeks to understand this difference — to explain what it is about the rational and purposive structure of behavior that makes it action rather than mere movement.

Historical Context

Aristotle provided the first systematic analysis of action in the Nicomachean Ethics. Aristotle distinguished between voluntary and involuntary actions: an action is voluntary when the agent knows what they are doing and does it without compulsion, and involuntary when it is done under force or through ignorance. This distinction is the foundation of moral responsibility — we are praised or blamed for voluntary actions but not for involuntary ones. Aristotle also analyzed choice (prohairesis), which he defined as deliberate desire for things in our power — the intersection of desire and deliberation that produces intentional action.

Aristotle's analysis of practical reasoning — the reasoning that leads to action — was particularly influential. Practical reasoning, for Aristotle, starts from a goal (the good to be achieved) and moves through deliberation about means (how to achieve it) to a conclusion that is not a proposition but an action. The structure is: I want to be healthy; being healthy requires exercise; so I exercise. The conclusion of this reasoning is not the judgment "I should exercise" but the action of exercising itself. This insight — that practical reasoning culminates in action rather than judgment — remains central to the philosophy of action.

Descartes transformed the philosophy of action through his dualism. For Descartes, the mind and body are fundamentally different substances — the mind is thinking, unextended substance, and the body is extended, unthinking substance. Action, for Descartes, originates in the will — the mind's capacity to choose — and is executed through the mind's causal influence on the body. This raises the problem of mind-body interaction: how can an unextended mind cause a body to move? Descartes's answer — that the interaction occurs in the pineal gland — was widely rejected, but the problem he posed shaped the philosophy of action for centuries. The Cartesian framework made the will central to action theory and raised questions about the causal role of mental states that are still debated.

The modern philosophy of action was transformed by two twentieth-century thinkers: Elizabeth Anscombe and Donald Davidson. Anscombe's Intention (1957) is widely regarded as the foundational text of contemporary action theory. Anscombe argued that intentional action is distinguished not by any accompanying mental state (like a feeling of willing) but by the form of practical reasoning through which it is produced. An action is intentional if it is the conclusion of practical reasoning — if the agent knows what they are doing not by observation but by knowing the reasons for which they are acting.

Davidson's 1963 essay "Actions, Reasons, and Causes" argued that the reasons for which we act are also the causes of our actions. This was controversial because many philosophers held that rational explanation (explaining an action by citing the agent's reasons) and causal explanation (explaining an event by citing its causes) are fundamentally different. Davidson argued that they are compatible: a reason is a cause when it actually produces the action, not merely when it rationalizes it. If I go to the kitchen because I want a beer and believe there is beer in the kitchen, my desire and belief are not just reasons that justify my action — they are the causes that produce it.

Philosophical Perspectives

The question "what is an action?" has received several competing answers. The simple view holds that an action is a bodily movement caused in the right way by an intention. On this view, raising my hand is an action because my intention to raise my hand causes my arm to rise in the normal way. But this view faces difficulties: some actions (like deciding, promising, or thinking) do not involve bodily movement, and some bodily movements (like reflexes) are caused by intentions but are not actions.

The competing view, associated with Anscombe and Davidson, holds that actions are events described under intentional descriptions. The same event can be described as a bodily movement (my arm went up), as a signal (I waved to my friend), or as a social act (I greeted someone). Whether the event is an action depends on whether it can be described as intentional — whether there is a description under which the agent did it intentionally. This view allows that actions need not be bodily movements and that the same event can be both an action and a non-action under different descriptions.

The question of intentional action has been equally contested. Anscombe's view is that an action is intentional if it is the conclusion of practical reasoning — if the agent knows what they are doing in a practical, non-observational way. When you intentionally walk to the store, you know that you are walking to the store not because you observe yourself walking but because you know your reason for walking. This practical knowledge is constitutive of intentional action: it is not an additional mental state that accompanies the action but part of what makes the action intentional.

An alternative view, the belief-desire theory, holds that an action is intentional if it is caused by the agent's desire for an outcome and belief that the action will produce that outcome. On this view, intentional action is behavior caused by the right kind of psychological states. This view is popular in the philosophy of mind and cognitive science but faces the challenge of distinguishing genuine intentional action from behavior that is caused by desires and beliefs but is not intentional — like a nervous tic caused by a desire to relieve anxiety.

The reasons-causes debate, initiated by Davidson, remains one of the central controversies. Davidson argued that reasons are causes: the reason for which an agent acts is the cause of the action. Against this, some philosophers argue that rational explanation and causal explanation are fundamentally different kinds of explanation. To explain an action by citing the agent's reasons is to make it intelligible — to show why it made sense for the agent to do what they did. To explain an event by citing its causes is to show how it was produced — what mechanism brought it about. These are different explanatory projects, and conflating them may obscure the distinctive character of rational action.

The problem of agency — what it is to be an agent — has become increasingly central. Some philosophers, following Harry Frankfurt, argue that agency involves not just desires and beliefs but higher-order attitudes: the capacity to reflect on one's own desires and to identify with some rather than others. A person who acts from a desire they endorse is exercising agency in a fuller sense than a person who acts from a desire they wish they did not have. This hierarchical model of agency has been influential in discussions of free will, autonomy, and moral responsibility, connecting the philosophy of action to broader questions about the nature of the self.

Modern Reflection

The philosophy of action has become increasingly relevant to contemporary debates in ethics, cognitive science, and artificial intelligence. In ethics, questions about intentional action underlie debates about moral responsibility, criminal liability, and the distinction between intended and foreseen consequences. The doctrine of double effect, which distinguishes between harms that are intended and harms that are merely foreseen as side effects, depends on a philosophical account of intentional action that remains contested.

In cognitive science and neuroscience, the philosophy of action intersects with empirical research on the neural basis of action. Benjamin Libet's experiments, which appeared to show that the brain initiates action before the agent becomes aware of the decision to act, have been widely discussed as a challenge to the traditional picture of conscious agency. If the brain decides before the mind is aware, does that mean that conscious intention does not cause action? Philosophers of action have responded by questioning whether Libet's experimental setup captures genuine intentional action and by distinguishing between different kinds of decisions and intentions.

The rise of artificial intelligence raises new questions for the philosophy of action. Can an AI system be an agent? Can it act intentionally? If a self-driving car decides to swerve to avoid a pedestrian, is that an action in the philosophical sense, or is it merely a complex causal process? These questions force philosophers to clarify what is essential to agency — whether it requires consciousness, rationality, self-awareness, or something else — and to consider whether artificial systems can possess the relevant capacities.

The question of free will remains intimately connected to the philosophy of action. If every action is caused by prior events, then in what sense is the agent free? If reasons are causes, as Davidson argued, then does rational action leave room for genuine freedom? The philosophy of action provides the framework within which these questions are asked, and the answers we give shape our understanding of moral responsibility, human dignity, and the nature of personhood.

The deepest question the philosophy of action asks is also the simplest: what is it to do something? We act constantly — we speak, we move, we decide, we refrain — and yet the nature of action remains elusive. Is action fundamentally a causal phenomenon, a rational phenomenon, or something that cannot be fully captured by either causal or rational explanation? The tradition from Aristotle through Anscombe and Davidson suggests that action is both — that it is behavior that is caused by reasons, animated by purpose, and shaped by the agent's understanding of what they are doing. Holding these dimensions together is the challenge that the philosophy of action continues to address.

Related Thinkers

• Aristotle — provided the foundational analysis of voluntary and intentional action, distinguishing actions done by choice from those done under compulsion or ignorance, and developing the theory of practical reasoning
• Descartes — placed the will at the center of action theory, arguing that action originates in the mind's free choice and is executed through the mind's causal influence on the body

Related Books

• Nicomachean Ethics — Aristotle's foundational text on ethics and action, containing the classic analysis of voluntary action, choice, and practical reasoning
• Meditations on First Philosophy — Descartes's masterwork on the nature of mind, body, and the will, which shaped the modern understanding of action as originating in mental causation

Related Quotes

• "The origins of action are choice, and that of choice is desire and reasoning with a view to an end." — Aristotle, Nicomachean Ethics
• "The will is so free in its nature, that it can never be constrained." — Descartes, Meditations on First Philosophy
• "What is the difference between an event that is an action and one that is not?" — G.E.M. Anscombe, Intention
• "A reason is a rationalization only if it is not also a cause." — Donald Davidson, "Actions, Reasons, and Causes"

Related Topics

• Purpose — action is purposive behavior, and the philosophy of action is fundamentally concerned with how purpose animates and directs behavior
• Knowledge — intentional action involves practical knowledge — knowing what one is doing — which raises questions about the nature of this distinctive form of knowledge
• Epistemology — the theory of knowledge, which provides the framework for questions about practical knowledge and self-knowledge in action
• Metaphysics — the study of the fundamental nature of being, within which questions about the ontology of action and causation arise
• What Is Free Will? — the question of whether agents can freely choose their actions, intimately connected to the philosophy of action
• What Is Purpose? — the concept of purpose that animates intentional action and gives it its directed character

Further Learning

To deepen your understanding of philosophy of action, explore these connected resources in the ZHAIBIAN archive:

• Epistemology — the full philosophy entry examining knowledge, justification, and practical reasoning
• Metaphysics — the systematic study of being, within which questions about the ontology of action and causation arise
• What Is Free Will? — the question of whether agents can freely choose their actions and what this means for responsibility
• What Is Purpose? — the concept of purpose that gives action its directed and intentional character
• Purpose — the wisdom entry on the intentional structure of a life directed toward ends
• Knowledge — the wisdom entry on the nature and limits of human understanding
• Understanding Yourself — the curated collection on self-knowledge, agency, and the examined life