Introduction

Picture a familiar scene: a cue ball goes rolling across the pool table toward the 8-ball. When the cue ball makes contact with the 8-ball, the 8-ball suddenly starts rolling too. If someone then asks, “why did the 8-ball start rolling?”, you’d likely answer “when the cue ball hit the 8-ball, it caused the 8-ball to roll”. The answer seems obvious enough, and fairly uninteresting as well. But the apparent simplicity of the case is quite deceptive. If you actually believe that the cue ball’s hitting the 8-ball caused the 8-ball’s movement, then you just might not believe in free will—at least not really.

The Problem of Free Will

Free Will

Before we can explain why it is that if you think the cue ball’s hitting the 8-ball caused the 8-ball’s movement, then you can’t believe in free will, we need to first get an idea of what free will even is. Roughly, we can take Free Will to mean that when you do something, it’s because you chose to do it, and not because something else made you do it.

We can get a clearer idea with an example. Think about when you’re at a restaurant, flipping through the menu and deciding what to order. That moment of choice, where you pick one dish over another, is a prime example of free will in action. As you’re sitting there, scanning the menu, you take notice of some set of options that interest you. You could choose the burger, the salad, or maybe even the pasta. In the process of deciding, you weigh the different option with respect to your own mental states. That is, with respect to your beliefs and desires. Maybe you want to lose weight, and maybe you also believe that you don’t have enough money for both pasta and dessert. So, on the basis of these beliefs and desires you have, you choose the salad.

When you finally settle on the salad, it’s not because someone or something else made that decision for you. It’s because you weighed the options, considered your preferences, and landed on the choice given your own beliefs and desires. That’s the essence of free will—your actions are determined by nothing other than yourself.

But why do we believe in free will? Well, in situations like ordering food, it seems pretty straightforward. You know what you like, you know what you’re in the mood for, and you make your selection accordingly. It’s a small but tangible demonstration of your ability to navigate choices and assert your agency in the world. However, the concept of free will extends beyond just picking dishes at a restaurant. It’s about the broader idea that you have the power to shape who you are. It’s about recognizing that you’re not just a passive observer in your own life, but an active participant in shaping its course.

While ordering food might seem like a trivial example, it serves as a nice example that will help us get a better understanding of the larger philosophical debate surrounding free will, including questions about autonomy, determinism, and the nature of human agency. So, now that we have a basic picture of what free will is, we can move on to understanding why you don’t have it.

Causal Determinism

When you said the cue ball caused the 8-ball to move, there’s a few things you might have meant by cause. But it’s most likely that what you meant by cause in this example is something philosopher’s call Causal Determinism. Causal determinism is the view that all events (like an 8-ball rolling across the table or an arm reaching out for a pen) have a cause that determines or rather guarantees that event’s outcome. This will be easier to understand with an example.

When the cue ball hit the 8-ball, the 8-ball rolled in a particular way. That is, it rolled some particular distance from its starting point—maybe it rolled 2 feet. But it also rolled at a particular speed, in a particular direction, and on a particular trajectory. So, ultimately when the 8-ball got hit it moved to a specific location on the table—let’s say it stopped just short of the corner pocket—and it got there in a specific way. What the causal determinist is saying when they claim a cause guarantees an event’s outcome is this: The 8-ball’s rolling in that particular way to that particular spot was caused by the cue ball hitting it, such that every time the cue ball hit’s the 8-ball under the same conditions, the 8-ball will roll in this particular way to the same particular location.

Of course, what the causal determinist doesn’t think is that every time a cue ball hits an 8-ball, the 8-ball will roll exactly how our 8-ball rolled. Instead, what the causal determinist thinks is more refined. The 8-ball isn’t the only thing behaving in a particular way. The cue ball also hit the 8-ball in a particular way—at a particular speed, in a particular location of the 8-ball, and so on. This matters for the determinist position. Remember, the cause guarantees the event’s outcome. So, that means the precise nature of the cause matters for how an event unfolds. So, every time the cue ball hits the 8-ball the particular way the cue ball hit the 8-ball in our example, only then will the 8-ball roll the particular way it did in our example.

When you told your friend that the cue ball caused the 8-ball to roll, this is what you really meant. You were just committing yourself to the causal determinist picture of the world.

So, why wouldn’t you be a causal determinist? All of this seems plausible enough if not obviously true—this is especially the case for pool. Watch videos of professional pool players or people performing trick shots, and what you’ll see is they can reliably hit the cue ball in a particular way which in turn guarantees that the cue ball will hit the 8-ball in a particular way, ultimately guaranteeing a particular movement of the 8-ball. Even you—with enough coordination, an intuitive understanding of the relevant physics, and knowledge of basic geometry—can play pool well enough such that you can guarantee what happens when you hit a ball. What this all suggests is that an event’s causes really do guarantee that event’s outcomes. After all, if any one of us can become good enough at pool such that we can guarantee where a particular ball ends up on the table that means there are some causal laws governing how pool balls interact, and that I’ve somehow come to have knowledge of those laws.

So, what’s the problem with being a determinist? Well as I mentioned at the outset, it means you don’t have free will. But why not? Well, importantly determinism doesn’t come à la carte. It’s a physical law governing every physical object in our universe. That means that every physical object—including you—is really just a complex pool ball.

What this means is that every event is the determined product of some previous cause. And just like with our pool balls we can trace our causal chains back until we find some initial cause. For instance, the cue ball’s hitting the 8-ball was itself caused by a previous event—namely you hitting the cue ball. If we apply this to universe more generally, then we can trace every cause back to some initial event that was responsible for everything—the beginning of the universe, God, the big bang, or whatever.

You might begin to see why this is a problem for free will, but we can make it more explicit with an example. Suppose in the future that we develop a superintelligent computer with what seems like an unlimited amount of processing power. And suppose that we also have a complete physics. That is, we know exactly what the universe was like at its initial moment, and we know every physical law that governs our universe. If we were to give all of this information to our supercomputer, then it should—according to the causal determinist—be able to predict all the events that will follow up until the end of the universe with absolute certainty. That is, all of our computer’s predictions will have 100% accuracy. And again just like you and your knowledge of pool, the computer is able to do this only because it has some knowledge of the laws that govern how physical objects interact.

But crucially, our computer will also be perfectly predicting your behavior as well. This is a problems for free will because the only information the computer was given was the laws of the universe and the initial conditions of the universe—something that precedes your birth by billions of years. But remember, you have or rather express your free will only when your actions are determined by nothing other than yourself—or to be more precise, nothing other than your beliefs and desires. So, without any knowledge of your psychology—of your beliefs, desires, and goals—our computer will be better equipped to know what you will do than you yourself. So, how then can we say that any of your actions really are caused exclusively by your own beliefs and desires? In such a case, how could you possibly have free will?

Sketch of the Landscape

So, we’re left with an apparent contradiction between free will and causal determinism. If we accept that we live in a causal deterministic universe—that causes determine their event’s outcomes—then we don’t have free will. And if you accept that we do in fact have free will, then you must reject that we live in a causally deterministic universe. This position that free will and causal determinism are incompatible has a rather apt name: Incompatibilism. And while these two views appear incompatible, some philosophers think this incompatibility is merely apparent. That is, while it looks as though these two theses are incompatible, they are actually quite easily compatible with each other. This position is known as Compatibilism. In what follows, we’ll sketch an account of two incompatibilist positions—hard determinism and libertarianism—as well as the compatibilist position. Let’s begin with the Hard Determinist.

Hard Determinism

The Hard Determinist accepts the apparent contradiction between free will and causal determinism. And they come down—as their name suggests—on the side of causal determinism. That is causal determinism is true. And because causal determinism is true and incompatible with free will, that must mean that causal determinism is false. Essentially, hard determinists argue that our actions are not products of our own decisions but rather the predetermined consequences of some prior sets of causes. Every event, whether it be the movement of pool balls or human behavior, is claims to be governed by a chain of causation. For instance, when the cue ball hits the 8-ball on a pool table, the motion of the 8-ball is not the result of independent choice but rather, an outcome determined by the laws of physics. This we can all agree on. The controversial claim of the hard determinist is that we too are mere pool balls whose behavior is determined likewise.

In understanding the rationale for taking up such a controversial position, it’s important to note that the causal determinist is something of a hard-nosed defender and advocate of science. Our best scientific picture of causality, according to the hard determinist, is causal determinism. And if we wish to have a properly scientific understanding of human behavior—a scientific psychology—then a scientific picture of the causes of human action will be a causally deterministic one. If there is no room in that picture for free will, then we simply do not have free will.

But what do we make of the fact that it seems as though we really do have free will? The hard determinist says that it is merely a subjective experience that we have, and an illusory one at that. When it seems like my choosing the salad at the restaurant was caused by my belief and desires, that was an illusion. My choice and the subsequent action were really caused by some physical mechanisms outside of my control such as some unconscious neural processes which were caused by some underlying biological and chemical facts about me. But in those processes we can find nothing that we might call free will.

Importantly in making their case against our having free will, the hard determinist need not rely on their commitment to a scientific picture of human psychology. Nor must they rely on their deeper commitment to causal determinism, and the claim that all human actions are ultimately caused by the big bang or something like that. So if you find these pictures implausible, consider the following argument instead.

Again, it’s essential to note that our having free will requires that our actions are caused by nothing but our own psychological states. That is, an action is free only when it stems from my beliefs and desires alone. But there’s an immediate problem here. If all that can be causally responsible for my action is my own beliefs and desires, then it means that my beliefs and desires too must be caused by nothing outside of my own psychology. And it seems fairly straightforward that this cannot be the case. Some combination of factors including genetics, upbringing, and cultural influences significantly shape my psychological makeup. And all of these factors lie outside of my control.

Genetics play at least some role in determining an individual’s psychology, influencing everything from personality to cognitive abilities. Similarly, upbringing and environmental factors during one’s formative years contribute to the development of beliefs and values. Cultural influences further shape individuals’ perspectives and decision-making processes, introducing social norms and expectations that influence behavior. This is all to say that the beliefs and desires that any person has were in part determined by things outside of their control. I certainly can’t control my genetics. I didn’t choose how my family raised me. And when cultural factors influence me the most—during childhood and adolescence—I can’t exert much force over them. So, even if my beliefs and desires cause my actions, they cannot do so in a way that saves free will because to do so, they would need to have been formed free from external causes. And it seems that this simply cannot be the case.

While the hard determinist position has good support, it also has its problems. In particular, it’s not clear what real philosophical and practical implications follow from the hard determinist position because after all, I still have to act as though I have free will. Even someone fully committed to the hard determinist position must act as though they have free will.

For instance, let’s imagine what the hard determinist would do at a restaurant. When faced with the choice of what to order, they cannot simply sit idly and expect external forces to cause their decision. They’ll never get any food on the table, and the server will stand there wondering if they’re ok. Instead, they must actively deliberate and make a choice based on their beliefs and desires. While they argue against the existence of free will, they are unavoidably bound to act as though they possess it in their daily lives. If they didn’t, they couldn’t do anything.

The hard determinist has responses to these objections. But we won’t talk about those here. Instead, we’ll move on to libertarianism.

Libertarianism

The Libertarian position on free will—like the hard determinist—asserts that free will and causal determinism are fundamentally incompatible. However, unlike the hard determinist, they claim that free will is true, and deny causal determinism. It will be important to note that while some libertarians deny we live in a causally deterministic universe, others do not. Rather, they only deny that causal determinism governs human behavior. It’s this latter version of libertarianism that we’ll be considering here.

While the hard determinist prioritizes scientific principles in understanding human behavior, the libertarian chooses a different route. They focus on human experience over scientific principles. According to libertarians, we experience the world in a particular way. Namely, have an intuitive and felt sense of agency and autonomy. We feel as though our choices and our deliberations about those choices matter. They matter because they seem to be what is guiding our actions. And understanding this felt sense of sense of control that we have over our own actions is important if we ever want to understand anything about ourselves. So, we can’t simply throw out free will because it contradicts our scientific principles. We’re better off abandoning the scientific principles.

It’s important to note here that the libertarian doesn’t want to deny the possibility of a scientific psychology or even to suggest that current scientific principles can’t be useful in coming to understand human action. Rather, their claim is something like our feeling of control is an important part of our psychology. And we cannot simply dismiss it out of hand as an illusion because it contradicts. According to the libertarian, any good scientific psychology should be able to speak to all of the facets of real human experience. And if we experience ourselves as having free will, then our scientific need to be able to speak to that.

The immediate problem for the libertarian comes from their denial of causal determinism. The libertarian needs to be able to say how our actions are caused by our beliefs and desires. But in denying causal determinism, they don’t have a story about how our beliefs and desires can cause human action. And if our actions aren’t caused by our beliefs and desires, then it seems as though free will is off the table from the jump for the libertarian. (We’ll return to this argument in the section on compatibilism.) More precisely, what they deny is a picture of cause where objects cause the movement of other objects by bumping into them and transferring motion to them. But this is the only picture of causality that we have, and it’s the one that justifies causal determinism being true. So, the libertarian needs to give us an alternative conception of causality if they want to save free will.

The way the libertarian goes about doing this is by positioning something they call agent causation. Unlike the deterministic causation observed in physical events, agent causation suggests that humans possess a unique capacity to initiate actions independent of external influences. But how does it work? Libertarians are unfortunately tight-lipped on this. One way in which they develop this notion of agent causation is by an appeal to the distinction between doing and making happen. The distinction between doing and making happen is, like agent causation, an underdeveloped concept. But we can use some examples to get clearer about it.

Consider a simple action like grabbing a cup or hitting a cue ball with the stick. In each of these cases there are events that I “do”. These events that I “do” are the actions that I intended to perform such as grabbing the cup or hitting the ball. These are normal causes. But there are other events that are caused as well. In grabbing the cup, the air between my hand and the cup dispersed. In hitting the ball, some chalk on the tip of the stick might disperse int the air as well. But I didn’t do these things. Rather, I “made them happen”.

We can move on to a more interesting case of a causal chain. Take the pool example again. When the 8-ball rolls there are a series of causes responsible for its movement. It was hit by the 8-ball. The 8-ball was hit by the stick. The stick was moved by my hand. And my hand was moved by neural activity in my brain. These are all cases of things being done. Some outside force acts upon an object and transfers motion to that object. Thus, causing its movement. But the libertarian wants to pause here and ask two questions. What caused the neural activity? And in what way was it caused? The traditional notion of cause as transfer of motion cannot account for this question. Nothing collides with the relevant parts of my brain in such a way that it can transfer motion and cause neural activity. Rather, the libertarian suggests brain activity is something that is made to happen. And it is somehow made to happen by me.

You might be tempted to ask how I make the neural activity happen. And the libertarian fails to offer a good response here. This we might take as the real critique of the libertarian position. They offer interesting and useful concepts that might be able to save free will. But they are undertheorized. And thus, it becomes hard to justify using them. The libertarian will of course respond that in due time, we might get a clearer picture of how they work. But for now, let’s move on to another attempt to save free will.

Compatibilism

So far, we’ve looked at two different approaches to deal with the contradiction between free will and causal determinism. The compatibilist takes a different approach than the hard determinist and the libertarian. They reject that these two theses are actually incompatible. The Compatibilist position on free will seeks to reconcile the apparent contradiction between free will and causal determinism by arguing that they are, in fact, perfectly compatible. They go about doing this in two ways. First, they aim to show that free will actually requires that causal determinism is true. And second, they attempt to redefine free will in a way that will align with causal deterministic principles while maintaining its significance.

The compatibilist wants to show that free will requires causal determinism to be true. Unlike hard determinists who reject free will in favor of causal determinism, and unlike the libertarian who reject causal determinism in favor of free will, compatibilists argue that free will can coexist with deterministic causal processes. The reasoning behind the compatibilist position is a problem that crept up when discussing libertarianism. If our actions are going to count as free actions, then they need to be caused by our beliefs and desires. This is because our actions need to be a product of our own psychology if they are going to be free. And so, if they are not caused by our beliefs and desires, it begins to look like they’re random.

Consider the restaurant example. Suppose you’re at the restaurant, and you engage in all this deliberation about what you want to order. And you set your mind to ordering the salad. But then all of a sudden and without your control, you say to the server, “I’ll have the pasta”. You at no point made the decision to order the pasta. And you didn’t intend to say to the server that you’ll order the pasta. It was almost as though your speaking of the words “I’ll have the pasta” was a kind of reflex, a twitch, or a tic. This is what the compatibilist thinks is going on if your beliefs and desires don’t cause your actions. Everything you do is really just a kind of twitching. And twitches and reflexes clearly cannot be counted as being free action. These kinds of actions are defined as being outside of one’s control. So, there needs to be something internal that is the cause of your action if you are going to have free will.

But why not take the libertarian route of positing some sort of agent causation? There are two reasons. First, we might not want to accept a concept that isn’t well defined. This is particularly true when we already have useful enough concepts like beliefs and desires as well as a way to understand how these states can cause human actions. But second, we also don’t just want our beliefs and desires to cause our actions. We want them to causally determine our actions. That is, we want our beliefs and desires to cause our actions in such a way that my having particular beliefs and desires in a particular context will always cause a particular action.

Let’s go back to the restaurant example. In the restaurant when I decided to order the salad, I did it on the basis of my beliefs and desires. But it wasn’t just that I had certain beliefs and desires that caused me to order the salad. I also deliberated on those beliefs and desires. I ordered the salad because I want to lose weight, and I believe that ordering the salad is the best option to achieve that goal. I also want to save money, and I believe that the salad is the cheapest option. This is to say, on the basis of my beliefs and desires, I engaged in some sort of rational practice. And that rational practice is an inherently causally deterministic one. I know that ordering the salad will cause me to spend less money. That’s why I ordered it.

Free will on this view then not only requires that we act from our own psychology, but also that we do so in a rational way. This doesn’t mean that all of our actions must be entirely and perfectly rational, but rather that we act so as to achieve our goals because those are the things driving our behavior. To get clearer on this, the need for our beliefs and desires to not merely cause our actions but to causally determine our actions is due to the fact that our reasoning is causally deterministic. And so, the process by which our beliefs and desires cause our actions must also be causally deterministic.

What then of the worry that free will requires only our psychology can cause a free action and our psychology is beyond our control? The compatibilist position is to deny that free will requires that nothing outside of ourselves causes our actions. To support their position, compatibilists highlight the role of rationality in shaping human behavior. They argue that genuine freedom lies not in the absence of causal influences but in the capacity to engage in rational decision-making and adjust one’s beliefs and desires in response to external stimuli. To act independently of external factors that can change and alter our beliefs and desires, is to act irrationally. That is, it is to act in a way that is not helpful for achieving one’s goals. And so, the compatibilist wants to maintain that this cannot be what free will consists of.

Now all that’s left is a critique of the compatibilist position. But, by now you should have a pretty good handle on the contours of the debate surrounding free will. So, I’ll leave that one up to you.

Conclusion

So, we’ve now gone through the problem of free will and three different positions on how philosophers attempt to solve the puzzle. It’s important to note here that the solutions are not merely accepting or denying some thesis or other. The hard determinist of course does just reject free will, but they are the originators of the problem. And although it might seem as though the libertarian is merely rejecting causal determinism, what they’re doing is actually closer to the compatibilist. What the compatibilist is doing is attempting to redefine free will in a way that is true to our actual experience of free will, but which does not come at the cost of having to reject causal determinism. The libertarian is doing something closer to this but with our concept of causality. They actually seek to offer an additional way we might understand causality—one which won’t come at the cost of giving free will.

Both the compatibilist and the libertarian are engaged in one of many important but hard practices in philosophy. They are trying to reinterpret and redefine our concepts so that we aren’t forced to choose which theses we want to maintain and which apparently incompatible we want to throw out. Rather, the project is to see if we can get a clear and accurate picture of our world without having to give anything up. Hopefully now, you can do the same.

Comprehension Questions

1. We talked about three positions one might have with respect to the problem of free will. First, rank them in order of plausibility. Then, briefly (in only 3-5 sentences for each view) explain why you find those views plausible or implausible.
2. Pick the view you ranked in the second position from question 1. And in more detail explain why you ranked it the second most plausible (or second least plausible depending on your perspective). Is there anything that could be added to the position or removed from—while not changing the nature of the position—that would make it more plausible than your first choice? Explain your reasoning.
3. At the end of the chapter, we discussed a way to see similarities in what the compatibilist and libertarian are up to. They’re both attempting to redefine a concept that ultimately is consistent with how we seek to understand that concept. Attempt to do this yourself. That is, attempt to redefine or reinterpret free will or casualty in a way different from how we define it here (and also do so differently from how the compatibilist and libertarian do this, respectively) that will make it consistent with the other concept.

Reading Suggestions

Primary Sources

Aristotle, Nicomachean Ethics (Book III, Chapters 1-5)

Edwards, Jonathan, Freedom of the Will (Parts I and IV)

Hume, David, An Enquiry Concerning Human Understanding (Section VIII: “Of Liberty and Necessity”)

Mill, John Stuart, On Liberty

Spinoza, Baruch, Ethics (Part II: “Of the Nature and Origin of the Mind” and Part III: “On the Origin and Nature of the Emotions”)

Secondary Sources

Dennett, Daniel, Elbow Room: The Varieties of Free Will Worth Wanting

Pink, Thomas, Free Will: A Very Short Introduction

Gazzaniga, Michael Who’s in Charge? Free Will and the Science of the Brain