According to the 2020 PhilPapers survey, 59.2% of philosophers are compatibilists when it comes to the free will/determinism debate. Despite its popularity among professional philosophers, what are the strongest criticisms/arguments against compatibilism levelled by incompatibilists? Please elaborate on the criticism/argument, and cite the philosopher(s) who made it, if possible.

  • I'm inferring the vote to close is predicated upon the scope of the request w/o looking. It's best to think of this site for acquiring guidance, analysis, and references on the philosophical canon rather than ChatGPT. ; ) I'm not voting to close, but for future reference you might want to limit your scope.
    – J D
    Oct 5, 2023 at 17:35
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    These sorts of broad inquiries are addressed by reading encyclopedias, e.g. IEP, Arguments for Incompatibilism. Questions here should be more specific.
    – Conifold
    Oct 5, 2023 at 17:45
  • Wikipedia's article on compatibilism has a criticism section, which is probably a good start, before getting into the more hefty philosophy resources.
    – NotThatGuy
    Oct 6, 2023 at 8:58

5 Answers 5


I will try and get this ball rolling, not to be exhaustive. However, a caveat first: i don't know that we can classify any of the following arguments as "best". For one because there are very few such arguments, and for two because each of those argument is tributary to a certain world view, and doesn't work outside of it. You can't really compare them.

  1. Cartesian Dualism: the oldest argument so I will start here. Descartes believed in determinism and postulated that a machine cannot be imagined as thinking. I.e., if one imagines our brain as a machine, with cogs and wheels, nowhere can one imagine a wheel or a cog that thinks, or a material, extended machine that creates non-extensive, immaterial thoughts. Therefore we cannot think of ourselves as only machines. Hence the need for something else than the material in us: the substance of soul.

  2. Somewhat similar, the Jansenist argument that man is indeed a machine, chained to the wheels of determinism just like any animal is, but unlike animals man has access to God's grace that can occasionally "save" the man machine from its machinery. In this view, a compatibilist is someone who leaves no room for God in this world, who fails to see that only God can solve the contradiction between determinism and our natural sense of agency.

  3. The indeterminist argument, primarily put forth by Popper, states that determinism is probably false, or "not even false" (i.e. metaphysical), and thus that it is unwise and unphilosophical to accept it mechanically or uncritically as is so often the case since Spinoza and Leibnitz. From that perspective, the need for compatibilism does not arise. Compatibilism is just another (silly) way to accept determinism uncritically.

  4. The moral argument, that says in essence that compatibilism makes not enough of a difference between men and animals: the compatibilist argument could be used to prove that dogs and birds have free will. But then why don't we consider dogs or birds morally responsible for their acts? They are just following their instincts, desires and fears, but we human are supposed to do better than that: to examine our desires, to put our instincts in check, to control our fears. This is the essence of freedom, not just following our proclivities as the compatibilists argue (at least, I suppose, some of them).

  • Popper seems to have argued that some combination of randomness and determinism can give rise to free will, but, to paraphrase something I heard recently, it is unwise and unphilosophical to accept this mechanically or uncritically. To assume that something exists because we haven't disproven it's existence yet is highly problematic and puts the burden of proof in the wrong place.
    – NotThatGuy
    Oct 6, 2023 at 8:36
  • "the compatibilist argument could be used to prove that dogs and birds have free will" - this would only trivially follow if it would also follow that rocks have free will (in which case you're basically just using a different definition of "free will"). Otherwise you'd need to make a much stronger case arguing for conscious control over actions (which would have difficulty grouping humans and other animals together). But also, one could argue that moral responsibility is personal and what extends to others is more of a social responsibility.
    – NotThatGuy
    Oct 6, 2023 at 8:38
  • "only God can solve the contradiction between determinism and our natural sense of agency" - How exactly does God do this? What evidence do we have that God has done this? Simply asserting that {insert thing here} solves the problem does not, in fact, solve the problem. Also, "leaving room" for something (God) sounds a lot like an unjustified presupposition: to me, it seems far more rational to conclude that things exists based on what you observe, and that which cannot be concluded should be discarded, rather than inserting something into one's worldview regardless.
    – NotThatGuy
    Oct 6, 2023 at 8:48
  • @NotThatGuy I have sympathy for compatibilism, so I was not really putting forth my arguments against it. It was not what was being asked by the OP, in any case. I was just trying to get the ball rolling by recalling a few arguments I am somewhat familiar with. Hope this clarifies.
    – Olivier5
    Oct 6, 2023 at 10:18
  • @NotThatGuy Re. your comment on the Jansenist argument, I suppose that a God who created the universe can do anything with its creation. Note that such a "god of the gaps" is often invoked to explain the seemingly unexplainable, e.g. the emergence of life from unanimated matter, or the existence of symbolic thoughts in this world. It's a classic function of god(s) to help explain what we can't understand. Once again, it's not my argument and I agree that it is a bit facile, that it does not really explain much.
    – Olivier5
    Oct 6, 2023 at 10:26

Well, I'm not going to do a research paper for you, but Kant (possibly, see comments below), Schopenhauer, and Popper were all incompatibilists. These philosophers were very invested in human culture and ethics. That leads us to two prominent attacks on compatibilism.

First, metaphysical libertarianism is one flavor of incompatibilism which prizes the human spirit and free will and largely reject determinism as having any sway over human choice. This is subjective with principles of humanism and the primacy of people in understanding and interpreting experience. Physical determinism is downplayed or integrated into choice in Berkeley's subjective idealism.

On the other end of the spectrum, hard determinism advocates that physical determinism is so overwhelming, in the spirit of Laplacian determinism, that little sense can be made of free will. This is compatible with eliminative materialism where ideas like free will are largely relegated to the status of "linguistic illusion". Daniel Dennett was a fierce incompatibilist in his early years, but later moderated his position.

Of course, more information can be found in WP's articles on free will, compatibilism, and incompatibilism. I would also read Arguments for Incompatibilism (SEP).

  • ~Dons the quibbling hat~ Was Kant an incompatibilist, though? In the first Critique, he does say that every human action could, in principle, be inferred from prior conditions. It's just that the whole series of prior conditions is not an absolute in-itself force, either, though, so the indeterminism function (so to speak) comes in from the outside. Though he never pretended to explain how this might be so, it's almost as if Kant was a meta-compatibilist: trying to harmonize direct compatibilism and incompatibilism themselves, not just determinism and the generic sense of free will/choice. Oct 5, 2023 at 18:54
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    @KristianBerry Your command of Kant is far better than mine, but I would largely agree with your characterization he was a meta-compatibilist on the basis that transcendental idealism and the appeal to God's agency meant that the Laplacian determinism of Newton's space and time in some way had an interface with with Leibnizian Monadology of unknowable theological agency-determined substance in such a way that made it okay to have a universe in which both determinism and non-determinism were compatible metaphysically but incompatible logically in the lens of mind-body duality...
    – J D
    Oct 5, 2023 at 19:02
  • through an appeal to pre-established harmony. Is that a mere restatement of your ideas?
    – J D
    Oct 5, 2023 at 19:03
  • It's a good restatement of some of Kant's, I think. He does dwell on the issue of how God's creation of us might or might not undermine our free will even apart from in-worldly determination (this discussion is somewhere in the second Critique, IIRC). Oct 5, 2023 at 19:06

There's only one really good argument against compatibilism, and it's the claim that there is no free will. The difference between compatibilism and no-free-will is just a disagreement over which definition of "free will" is preferable. It's not a disagreement over matters of fact.

Where the compatibilist sees our actions are determined by physics and chooses to define the words "free will" in such a way that it remains meaningful and compatible with this situation, the no-free-will philosopher sees that our actions are determined by physics and thinks it's better to define the words "free will" in a way that is incompatible with this situation.

Pros of the compatibilist definition: the term "free will" remains meaningful and usable as a way to describe the physical process of how we make decisions.

Pros of the no-free-will definition: the term "free will" remains consistent with the naive notion, which comes in handy if you're trying to explain what's wrong with the naive notion.

There are other arguments against compatibilism. None of them are very good. Perhaps the strongest of them would be the concept that the world isn't totally deterministic, because of quantum physics. However, compatibilists do not necessarily believe the world is deterministic! Free will in compatibilism is defined as the condition where your motivations guide your actions, with motivations corresponding to certain physical patterns, and this guidance may occur whether determinism or non-determinism is the correct physics.

In any case, if your actions are determined by a coin flip in the equations of physics, does that really mean you're "free"? If my actions are totally random, I feel less free than if my actions are the result of what I want to happen. If I want to do A, but instead I find myself randomly doing B against what I wanted, then I'd feel like some external force is making me do things I didn't want to! And I'd try to take steps to reduce the influence of that force on me.

There is also the dualist objection to compatibilism, the idea that there's some mind-substance that's unbound from the laws of physics. This objection is wrong because dualism is wrong. Even if there were such a substance, you'd still call yourself free if you did what you wanted to, i.e. if your mental desires, within the mind-substance, caused your actions. So it's really no different from physical compatibilism, just with the addition (without evidence) of an extra substance.


The best argument against compatibalism is that our universe is not deterministic, so both hard determinism and compatibilist determinism are refuted by physics. See this answer for more detail on the physics refutation Deterministic or stochastic universe?

The three main worldviews of hard incompatibilism determinism, compatibilist determinism, and libertarianism, are just the three most popular, they are not the only views one can have on free will. Compatibilist-leaners may say the world might be indeterminist, but that most of our thinking is based on reasons, so that one can approximate our willing and choices by a near-determinist compatibilist model. This has been the response of several compatibilists I have encountered to the refutation of determinism -- basically a "near enough" pseudo-determinist plus random and pseudo-compatibilist POV. As Quine pointed out, there are basically infinite theories we can fit to all evidence, and one can no doubt construct all sorts of "near compatibilist" views, at least one of which has no refutations.


The best argument against compatibilism is that free will and determinism are incompatible by definition. Either agents decide or no-one decides. Compatibilism requires redefinition of both to enable "deterministic" decision-making.

The second best argument is that in reality there is no determinism to be compatible with. Compatibilism is a useless idea.

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