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Learning Objectives

By the end of this section, you will be able to:

  • Define free will.
  • Explain how determinism, libertarianism, and compatibilism are different.

Though the presence of evil in the world suggests that we have free will, the idea of a first mover or an all-powerful divine being challenges the idea that we might have free will in the material world. Throughout most of our experiences, it seems as if we are free. When we complete a task, we seem very capable of marking this experience as different from being free. But what if the sensation of freedom does not demonstrate the presence of freedom?

Amusement parks often have rides that consist of a car on a track that has safety features forcing the car to stay within predetermined paths. In most cases, there is an accelerator, a brake, and a steering wheel. Some rides have strategically placed rubber boundaries guiding the vehicle, while others have a steel post hidden underneath the car that guides the car by means of a predetermined tract. While “driving” the car, the young driver feels free to choose the direction. As vivid as the experience for the driver may be, the thrill and phenomenon does not prove the presence or existence of freedom! Similarly, does the feeling of being free demonstrate the presence of freedom in our actions?

Defining Freedom

To begin to answer these questions, this section first explores two competing definitions of freedom.

The Ability to Do Otherwise

Perhaps the most intuitive definition of freedom can be expressed as “A moral agent is free if and only if the moral agent could have done otherwise.” Philosophers refer to this expression as the Principle of Alternative Possibilities (PAP). A person is typically thought of as performing a free action if that same person could have taken a different action or decided to take no action. Within many legal systems, a person is not considered culpable if the action taken was forced.

One objection against the PAP is based on how we define our being. What if we as physical objects are governed by the laws of nature? We do not set our rate of velocity when diving into a pool, nor are we able to determine the force of gravity if we choose to enter the water “belly first”! Those outcomes are determined by the laws of nature. We, as objects, are governed by such forces. Does this mean, like the driver in the ride depicted above, that we never actually experience alternative possibilities? If so, then the possibility of freedom—a precondition for responsibility—seems absent.

What about socialization and the conditioning that follows from living in a society? Does the constructed set of norms and values lessen our ability to do otherwise? Given the external conditioning we all endure, can we assert that the PAP is a possibility?

The Ability to Do as One Wants

One possible objection to defining freedom through PAP was offered by Harry G. Frankfurt. Frankfurt argued that freedom was better understood not as the ability to do otherwise but as the ability to do what one wants (1971). Imagine that a deranged space alien barges into your room and produces a sinister-looking button. You are informed that the button will annihilate Earth if pressed. The alien laughs manically and demands that you eat a delicious pizza brought from your favorite pizzeria or the alien will press the button. You can feel and smell the freshness! In this case, most of us would argue that you are not free to do otherwise. But you could say that you not only want the pizza, a first-order volition, but given what is at stake, you want to want the pizza. You could be described as acting freely, as you are satisfying your first- and second-order volitions. You are free, as you are doing what you want to do.


Within the free will debate, libertarianism denotes freedom in the metaphysical sense and not in the political sense. A libertarian believes that actions are free—that is, not caused by external forces. We are free to plot our course through our actions. Existentialists further argue that our essence is the product of our choices.

A drawing of Jean-Paul Sartre shows just his head. He is wearing glasses and is not smiling.
Figure 6.12 Condemned to Be Free. Jean-Paul Sartre (1905–1980) was a leader in the existential movement. He once characterized the reality of freedom as condemnation, as through the existence of free will, a human being was therefore responsible for all actions taken. (credit: “Jean Paul Sartre for PIFAL” by Arturo Espinosa/Flickr, CC BY 2.0)

Many proponents of the libertarian view assume the definition of freedom inherent to the Principle of Alternative Possibilities (PAP). We are free if and only if we could have done otherwise at a specific time.

There are many challenges to this assertion. One objection, based on Benjamin Libet’s neuroscience-based experiments, suggest that many of the actions we perceive as free are, in fact, caused and determined by the brain.


The Libet Experiment: Is Free Will Just an Illusion?

This video, from the BBC Radio 4 series A History of Ideas, is narrated by Harry Shearer and scripted by Nigel Warburton.


The contrary view to metaphysical libertarianism is determinism. The determinist holds that human moral agents are not free from external forces. Our actions could not have been otherwise. Thus, action X at time T must occur.

Causal Closure of the Physical World

One argument used to support determinism is built upon the observation of causality. Baron D’Holbach (1723–1789), in his System of Nature, observed that we, like all other natural entities, are subject to and governed by natural laws of the universe. His so-called “hard determinism” posited that all our actions are outside of our control. Humans cannot escape the cause-and-effect relationships that are part and parcel of being in the world.

Causal Determinacy of the Past

Another argument used to support determinism is built upon the consideration of past experiences. Perhaps the simplest way to express the causal force the past holds on future events is to reflect on your first-person experience. How influential has the past been in shaping the decisions you make in the present? We use expressions that reflect this causal power—for example, I will not get fooled again, I guess I will have to learn from my mistakes, etc. What has happened in the past can, in the least, limit the event horizon of the present.

The power of the past is not limited to first-person experience. Our socio-economic status, for example, can be a powerful force in determining the actions we deem permissible. As Ralph Waldo Emerson once quipped, we tend to “don the knapsack of custom” without questioning the contents of the knapsack.

Another important distinction when discussing determinism is that of compatibilism. Some determinists will assume that free will is not compatible with determinism. An incompatibilist position asserts that due to the nature of freedom and our lack of control concerning our actions, we cannot be held culpable for our actions. A soft determinist will assume that free will is compatible with determinism. In order to salvage a sense of moral culpability, an incompatibility might challenge the definition of freedom in terms of the PAP. For example, if you consider Frankfurt’s framing of freedom of fulfilling higher-order volitions, then even when forced to take an action, it may have very well been the action you would have chosen if not forced to do so.

William James (1842–1910) offers a view called indeterminism in which the notion is that all events are rigidly controlled. What if there is the possibility that one small effect might be uncaused somewhere out there in the grand series of cause-and-effect sequences? Given the possibility that such an uncaused effect might occur, there is the chance that not all events are falling dominoes or events that must happen. Thus, even in a deterministic setting, an indeterminist can argue that the possibility of an uncaused act is a genuine one. By extension, your choices, your hopes, and the actions for which you should be praised or criticized cannot be treated without doubt as caused externally. These actions could be your own!

Think Like a Philosopher

Watch the video “Language: Contrastivism #2 (Free Will)” by Walter Sinnott-Armstrong.

Metaphysicians are concerned with freedom from causation. By contrast, ethicists are concerned with freedom from constraint. Contrastivism allows enough space for philosophers to contrast the different focuses and to appreciate the differences that these differences introduce. According to Sinnott-Armstrong, the net result is a cease-fire. How can you support or refute the contrastivist solution to the problem of free will?

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