Among the perennial questions of philosophy, free will remains one of the most difficult concepts to reconcile with modern science. On the one hand, our best natural science seems to point to a deterministic universe based on immutable laws of physics, yet on the other, our subjective experience seems to tell us that we have inherent freedom of choice and movement independent of the physical laws. How one chooses to reconcile this paradox largely determines where they stand in the free will debate.

In Just Deserts: Debating Free Will, philosophers Daniel Dennett and Gregg Caruso debate the philosophical merits and moral implications of two opposite and competing positions: compatibilism and free will skepticism (more on those terms shortly). 

In this article, I’ll provide my analysis of this debate, and, in the process, explain why I believe compatibilism to be fundamentally incoherent (as I believe Caruso successfully demonstrates). While not a free will skeptic myself, free will skepticism does appear to be the stronger position when compared to compatibilism.  

Let’s begin by defining some preliminary terms and concepts before we get to the debate. 

Preliminary Concepts

Do you believe that free will exists? Your answer depends almost entirely on how you reconcile free will with determinism. Let’s define those terms. 

Determinism: The thesis that facts about the remote past in conjunction with the laws of nature entail that there is only one unique future. 

Modern physics tells us that every event or effect has a preceding cause, and that if you know the causes, you can predict the effects based on immutable natural laws (quantum mechanics may prove to be an exception). Determinism holds that life, and in particular human beings—since they are part of the universe and composed of the same physical materials—are likewise completely determined by preceding physical causes. Choice is merely an illusion.

Free Will: The philosophical position that grants humans at least some capacity to choose between different courses of action independent of deterministic physical laws. 

The tension between the two concepts is obvious. How can we live in a deterministic world described by the immutable laws of physics yet make choices independent of those laws? It is along these two dimensions that we can work out the various positions one can take on free will, outlined in the following table:

Free WillCompatibilismIncompatibilism (Libertarianism)
No Free WillIncompatibilism (Free Will Skepticism)Incompatibilism (Free Will Skepticism)

We can conclude the following from the table: If you believe in the existence of free will but also in determinism, you’re a compatibilist (like Daniel Dennett). Otherwise, you’re an incompatibilist in one of three senses. If you believe in free will but not in determinism, then you’re a free will libertarian (this is distinct from political libertarianism). If you do not believe in free will, you’re a free will skeptic (like Gregg Caruso), whether or not you believe in determinism. Free will skeptics recognize that determinism rules out free will, but also believe that even if the universe is indeterministic (as some interpretations of quantum mechanics suggest), this quantum indeterminacy, based on chance, still rules out free will, at least in terms of how free will is traditionally understood. 

In summary, the positions you can adopt are as follows:

  • Compatibilism – you believe in free will and determinism and that the two are somehow compatible.
  • Incompatibilism – you believe that free will and determinism are not compatible in one of two ways:
    • Libertarianism – you believe in free will and that the universe is not deterministic.
    • Free Will Skepticism – you do not believe in free will (irregardless of whether the universe is deterministic).

In addition, we might include two further positions:

  • Indifference – This is more of an attitude than a belief. You could be indifferent to the subject in the sense that beliefs regarding free will have no practical effects on an individual’s actual behavior.
  • Withholding Judgment – you might decide to withhold judgment entirely, on the grounds that, because free will is a component of consciousness—and because we have no satisfactory explanation of consciousness—we therefore cannot have any satisfactory or definitive explanation of free will. In other words, whether free will exists or not cannot yet (or ever) be answered. However, since we feel that free will is not an illusion, we should treat it as real unless and until it is proven otherwise. 

I tend to fall into the latter category of withholding judgment. I’m not prepared to dismiss the idea of free will without first encountering a complete and persuasive scientific account of consciousness (of which there is none). 

Note that I am not religious, and do not believe in supernatural explanations of the “soul,” but at the same time, I recognize that our scientific understanding of the world is restricted based on our technological and cognitive limitations. Taking a cue from the late Christopher Hitchens, I believe in free will because I have no choice but to believe in free will—illusion or not. 

But the issue here is not the correct position to take concerning free will, or even the potential merits of free will libertarianism. The issue, rather, is the relative strength of free will skepticism versus compatibilism, as debated by Dennett (on the side of compatibilism) and Caruso (on the side of free will skepticism).  

The Debate

The debate between Dennett and Caruso centers on the question of whether or not human agents should ever be held responsible for their actions in the sense of deserving either praise or blame, not in the forward-looking sense of ensuring compliance with the law or upholding agreed-upon moral standards, but in the backward-looking, basic desert sense of whether or not the agent made the “correct” moral choice in the moment when they both knew better and could have acted otherwise. 

Caruso’s position is that, because the universe operates according to physical laws which are either deterministic or indeterministic (based on quantum mechanics), human agents, being a part of that universe, could not have acted otherwise than they did. There is only one unique future. Laws and moral standards evolve over time and influence reason-responsive individuals, but those laws and standards are less important in a retributive sense of punishing wrongdoers than in a consequentialist sense of establishing predictable and stable moral behavior. Just as we would quarantine an individual infected by a deadly virus to protect others—without blaming the infected individual—we should likewise punish or rehabilitate criminals to protect others without blaming criminals for actions influenced by factors ultimately beyond their control (which is consistent with determinism). 

Dennett’s position is more difficult to ascertain. He seems to agree with Caruso that determinism is true and rejects the label of retributivist. He retains a forward-looking consequentialist notion of moral responsibility, yet at the same time retains the language of basic desert, or the idea that an individual should be praised or blamed for their actions. This is the point, I believe, where Dennett’s position becomes incoherent.

Caruso is correct to point out that Dennett’s version of compatibilism is closer to free will skepticism than Dennett would like to admit, and that the major flaw with Dennett’s argument is that he is conflating the following two questions:

  1. Under the assumption of determinism, do agents actually have the control in action needed for them to be truly deserving of praise and blame, punishment and reward?
  2. Under the assumption of determinism, is it practically beneficial to hold agents morally responsible in the relevant desert sense?

Caruso charges Dennett with answering the second question as if he’s answering the first. It appears that this is correct, in that Dennett is simply trying to hold onto language for its instrumental value and not for its relation to genuine justice or fairness. 

During the debate, Caruso gets Dennett to agree to two propositions that demonstrate that Denett’s version of compatibilism is in fact free will skepticism in all but name.

First, consider the connection between determinism and a lack of free will. As the American philosopher Peter van Inwagen put it:

“If determinism is true, then there is some state of the world in the distant past P that is connected by the laws of nature to any action A that one performs in the present. But since no one is responsible for the state of the world P in the distant past, and no one is responsible for the laws of nature that lead from P to A, it follows that no one is responsible for any action A that is performed in the present.”

Dennett seems to agree with this assessment. Elsewhere in the debate, Dennett says:

“Yes, I accept that ‘if determinism is true, then all human behavior, like the behavior of all other things in the physical universe, is causally determined by antecedent conditions in accordance with natural laws.’”

Since Dennett conceded to the truth of determinism earlier in the debate, both Caruso and Dennett agree that there is only one possible future, and, therefore, that individuals can act in only one way due to factors beyond their control. If this is the case, then in what way can people actually deserve praise or blame, independent of Dennett’s desire for the deterrence of bad behavior or the encouragement of good behavior? How can you label human action that is fully determined to be the result of free will? The answer is that you can’t, at least not without twisting the definition of free will into an unrecognizable form. 

Dennett can say that we have different thoughts pulling us in different directions and encouraging different behaviors, and that free will is our capacity to make decisions based on the reconciliation of all of these competing thoughts and considerations. But if all thoughts and considerations are determined in the same way, based on “facts about the remote past in conjunction with natural laws,” then determinism still holds and behavior can never be praised or blamed in the basic desert sense because it is, on a fundamental level, predetermined.  

Dennett may argue that it is important to hold onto the language of basic desert, individual praise and blame, but this is for purely instrumental or consequentialist reasons. It doesn’t mean free will exists; it only means it’s desirable to believe that free will exists and that this leads to positive outcomes. But the heart of the debate should be on the substantive issue of whether or not free will actually exists, not on the merits of talking about it in a particular way.

Second, Caruso gets Dennett to agree with a further idea based on a thought experiment proposed by Immanuel Kant. Kant asked whether or not a murderer on a deserted island should be punished if the decision was made for all the island’s inhabitants to leave the island and scatter across the world, abandoning the murderer to live on the island in isolation, indefinitely. Since the murderer will never come in contact with another human being again, should he be punished or executed?

This hypothetical scenario cuts to the heart of the debate between the moral philosophy of consequentialism versus retributivism. If you adopt a retributivist position, you believe that the murderer should be praised or blamed for a moral action in which they had control over. If you adopt the consequentialist stance, you believe that punishment or rehabilitation should be pursued for the good of society but not simply as a punishment to an individual for an action that was fundamentally beyond their control. The retributivist wants to punish the isolated murderer; the consequentialist does not. 

So how does Dennett respond to this scenario? Like Caruso, he would not punish the isolated murderer on the deserted island. This makes him a consequentialist, not a retributivist. If the murderer was deserving of blame for the murder, Dennett should want to punish him. But he doesn’t, which could only mean that, in Dennett’s eyes, the murderer is not deserving of blame after all. In other words, Dennett has contradicted himself by holding onto the language of praise and blame and then not applying it in a situation that clearly calls for it. 

Dennett will probably want to say that the murderer is deserving of blame only within the system of morality established by the island’s inhabitants, and, if the island has no inhabitants, then there is nothing to be blameworthy for. But, as Caruso points out, this stance amounts to free will skepticism in all but name, because the free will skeptic will come to the same conclusion. An individual can either be worthy of praise or blame or not, and if punishment or rehabilitation can only make sense in consequentialist terms, then it makes more sense to say that free will simply does not exist. 

Dennett spends a considerable amount of time trying to defend his idea of self-control, or how an individual’s actions are dependent on a complex process of comprehension and reasoning. But even though this is true, all reasoning—including the correlating brain states and electrochemical neural activity—is still determined! If there is only one unique future, then talk of self-control, reason-responsiveness, and free will is purely linguistic, a way to talk about events that can have no impact on a universe both Caruso and Dennett have agreed is deterministic. This makes Dennett’s stubborn attachments to specific language and obfuscation of the substantive issues quite difficult to read. 


Readers can come to their own conclusions, but it’s difficult to see how this debate could have possibly been won by Dennett. For the most part Dennett is on the defensive, trying to justify the contradictions Caruso skillfully points out. Both Caruso and Dennett appear to agree on the substantive issues, yet Dennett, for some reason, feels the need to retain the language of free will and basic desert even though he’s doing so purely on what seems to be consequentialist or instrumental grounds. But his idea that individuals who could not have acted otherwise still deserve praise or blame is fundamentally contradictory, as Caruso repeatedly points out.

Just Deserts: Debating Free Will is available on

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