Hard determinism, also known as incompatibilism, is the belief that determinism is incompatible with the possibility of free will and moral responsibility.
What Is Hard Determinism?
In other words, hard determinists believe that every thought, action, and event in the world is predetermined by the chain of events that came before it. Nothing escapes this chain.
If this is true, they argue, free will is impossible. People cannot be truly morally responsible for their behavior.
William James (1842-1910) coined the term “hard determinism” in his 1896 essay “The Dilemma of Determinism” (James, 1896).
In the essay, James defines hard determinism as the “old-fashioned” version of determinism, which was purer and less cowardly than a newer version he called “soft” determinism. The names stuck.
Hard determinism is defined as a distinct version of determinism from soft determinism.
These two views disagree about one thing: can a person have free will inside a fully deterministic universe, where every event is caused by everything before it? Soft determinists say yes. Hard determinists say no.
Important definitions
- Determinism: “The philosophy that all events are predetermined, by the chain of events that came before them.” (Hoffman, 2023)
- Soft determinism (compatibilism): “The philosophy that determinism is compatible with the possibility of free will and moral responsibility for one’s actions.” (Hoffman, 2023)
- Hard determinism (incompatibilism): “The philosophy that determinism makes it impossible to have free will and moral responsibility for one’s actions.” (Hoffman, 2023)
Examples of hard determinism
The two worked examples below show how a hard determinist and a soft determinist read the very same choice differently.
Nagel’s example of the peach or the cake
Imagine you are going through a cafeteria line, and you come across the choice of whether to select a peach or a slice of chocolate cake.
You choose the cake, but think to yourself, “I could have chosen the peach instead.” What, exactly, does that thought mean? And is it true?
This is a hypothetical question used by philosopher Thomas Nagel (1937- ) to explain the concept of determinism, and the difference between soft and hard determinism. Both kinds of determinists agree that the events that led up to your choice were predetermined.
Soft determinists use this example differently. Nothing external forced you to pick the cake. The choice flowed from your own genetics, upbringing, and personality, not from coercion — and that, on their account, is all “free” needs to mean.
To study or to party?
Here is another practical example of how hard determinism can be applied in the real world. You have a big exam on Monday.
You must choose whether to stay home and study, or go out to a party with friends. Say you ended up staying home to study (good choice!). Did you make this choice out of free will?
Soft determinists and hard determinists would disagree on the answer to this question. Both types of determinists agree that your choice was predetermined — in other words, you would never have chosen to go to the party with your friends.
The table below compares how each position reads both examples.
| Example | Hard determinist view | Soft determinist view |
|---|---|---|
| Peach or cake | Choosing the cake was inevitable; you could not have chosen the peach, so you are not morally responsible for the choice. | The choice was predetermined, but since no one forced you to pick the cake, you still acted with free will and can be held responsible. |
| Study or party | Staying home was predetermined, so you did not act out of free will and cannot be held morally responsible, because you were always destined to study. | The choice was predetermined, but because no external force stopped you from going to the party, you acted with free will and can take responsibility for choosing to study. |
Arguments in favor of hard determinism
Hard determinism argues that if determinism is true, it is impossible to have free will or moral responsibility for one’s actions.
They believe the soft determinist view misses what it means to be truly free. Nothing about it was up to you, they say. If, as determinism dictates, all of a person’s thoughts and behaviors are predetermined before they are even born, then they can never be truly free.
To be free in any given moment, they argue, a person must be able to think, act, or choose differently than they ultimately did.
For instance, Kant (2002) referred to soft determinism as “wretched subterfuge…, a petty word-jugglery” because he believed that soft determinism misconstrued the idea of freedom.
A more modern example comes from psychologist Dan Wegner (1948-2013). Wegner disagreed too.
In his influential book The Illusion of Conscious Will (2002), Wegner argues that the conscious experience people feel as driving their behavior is in fact an illusion.
It comes after the act, not before it. The brain generates this feeling to make sense of behaviors already carried out.
On this view, free will is also an illusion, because all our behaviors were predetermined. It only feels like we chose freely, thanks to the illusion of consciousness the brain generates.
Arguments against hard determinism
Several distinct categories of critics disagree with hard determinism.
Some agree with hard determinists that determinism is true but instead argue that free will and moral responsibility are possible within a deterministic universe. They reject only the “impossible” part.
Others disagree with the premise of determinism altogether—libertarians—and others still argue that no matter the truth of the debate on determinism, free will is impossible.
Soft determinists disagree with hard determinists because the former believe that even if the universe is deterministic, one can have free will and moral responsibility for one’s actions.
To be free, they say, a person must have freedom from external forces compelling a particular choice. That is all soft determinism requires.
Harry Frankfurt (1929-2023) is an example of a soft determinist philosopher. Frankfurt (1971) defined several orders of desire to understand a person’s motivations. The idea is simple.
“What you want” is a first-order desire, whereas “what you want to want” is a second-order desire.
According to Frankfurt, even if determinism is true, one can have free will if their second-order desires align with their first-order desires.
Psychological research on people’s beliefs about free will
Recently, as philosophers have debated determinism, free will, and moral responsibility, psychologists have joined in to examine regular people’s beliefs about these issues.
Some research from psychology supports the idea that hard determinism often goes against people’s intuitions. That is surprising.
Nahmias (2011) shows that people have a difficult time understanding hard determinism at first, because they often confuse it with a similar but distinct phenomenon called bypassing. The mix-up matters.
Bypassing is a theorized phenomenon where our bodies act without the input of our minds. Hard determinism is different: the mind still has input, it is just that the mind’s choices are predetermined. Free will feels intact.
Another study found that how a question is worded makes a big difference to people’s answers.
Nichols and Knobe (2007) found that when people are asked, in the abstract, whether free will is possible under determinism, most say it is not. A concrete example changes that.
Given a specific, emotionally engaging example instead, people often switch to a soft-determinist answer.
Critical Evaluation
Soft determinism’s central move is to separate “caused” from “random”: the true opposite of a caused action is an uncaused, arbitrary one, not a free one. This lets psychology stay a deterministic science while still holding people responsible for what they do.
Hard determinists reply that this is cosmetic. If conscious deliberation is itself fully caused, relabeling it “free” does no real work.
Where to draw the line is also unclear. Freud’s psychic determinism challenges the compatibilist test directly: if a “conscious” choice is actually driven by a hidden unconscious wish, an action can look free by the surface test. The cause may still be unfree.
The evidence base is not equally strong on both sides either. The clearest environmental-determinist demonstration, Little Albert, is a single-participant case study with no control group, which raises real questions about how far it generalizes.
Contemporary Research
A key question is whether what people believe about free will actually changes how they behave. One large meta-analysis has tested this directly.
- Aim: Genschow et al. (2023) set out to establish, via meta-analysis, whether manipulating people’s belief in free will or determinism reliably changes those beliefs, and whether it reliably changes subsequent behavior.
- Method: the team meta-analyzed 145 experiments, including many unpublished studies sought out specifically to counter publication bias, that had manipulated free-will belief and measured either belief change or a behavioral outcome such as cheating or helping.
- Results: the manipulations reliably shifted people’s stated beliefs, but once the analysis corrected for small-study effects and publication bias, there was little consistent evidence that these belief shifts produced the claimed behavioral consequences.
- Conclusion: belief in free will versus determinism is genuinely malleable, but its real-world behavioral consequences are weaker and less consistent than earlier, smaller studies had suggested.
The behavioral-genetics picture has also grown more nuanced. Polderman et al. (2015) pooled 2,748 twin studies covering nearly 18,000 traits. They found an average heritability around 49%, confirming a pervasive genetic influence while still leaving roughly half of the variance to environment.
Neuroscience has grown more cautious too. Maoz et al. (2019) recorded EEG while participants made either arbitrary or deliberate, value-laden choices.
They found the classic pre-movement “readiness potential” was strongly reduced before deliberate decisions. This qualifies the hard-determinist reading of the evidence.
Real-World Applications
The hard/soft distinction is not only academic. It shapes real decisions in law, therapy, and policy.
In law, the defense of diminished responsibility rests on a soft-determinist test. Courts tend to hold people responsible only for their own reasoning, not coercion or severe mental disorder.
Therapy is no different.
The type of determinism a clinician accepts shapes the treatment offered. Behavior therapies such as systematic desensitization treat a problem as the product of a reinforcement history. They fix it by re-engineering the environment.
Humanistic approaches take the opposite view: growth needs treating the client as an agent. This changes what relapse means for treatment.
In forensic and rehabilitation policy, findings on the heritability of antisocial traits matter too. They feed debates about whether offenders are fully blameworthy agents or people shaped by biology and environment.
Key Takeaways
- Hard vs. Soft: Hard determinism says a fully caused universe rules out free will; soft determinism says a caused act can still be free if it flows from conscious choice.
- Origin: William James coined both terms in his 1896 essay “The Dilemma of Determinism,” dividing them by what kind of cause counts as free.
- True Opposite: Determinism’s real opposite is randomness, not free will — an uncaused, arbitrary act is not “free” in any sense that matters.
- Modern Evidence: People give hard-determinist answers to abstract questions but soft-determinist answers to concrete ones (Nichols & Knobe, 2007), showing framing shapes belief.
- Belief vs. Behavior: A 2023 meta-analysis of 145 experiments found that shifting people’s belief in free will barely changed their actual behavior (Genschow et al., 2023).
- Real-World Stakes: The distinction underlies legal defenses like diminished responsibility and shapes whether therapy treats clients as agents or as conditioned systems.
References
Hoffman, R. (2023). Soft determinism. Simply Psychology. https://www.simplypsychology.org/soft-determinism.html#:~:text=Soft%20determinism%2Fcompatibilism%3A%20The%20philosophy,moral%20responsibility%20for%20one%27s%20actions.
James, W. (1896). The dilemma of determinism. In W. James, The Will to Believe and Other Essays in Popular Philosophy (pp. 145–183). Longmans, Green and Co. https://doi.org/10.1037/11061-005
Kant, I. (2002). The Critique of Practical Reason. Project Gutenberg. https://www.gutenberg.org/files/5683/5683-h/5683-h.htm
Nagel, T. (1987). Free will. In T. Nagel, What does it all mean? A very short introduction to philosophy. Oxford University Press.
Nahmias, E. (2011). Intuitions about free will, determinism, and bypassing. In Robert Kane (ed.), The Oxford Handbook of Free Will: Second Edition. Oxford University Press.
Nichols, S., & Knobe, J. (2007). Moral responsibility and determinism: The cognitive science of folk intuition. Noûs, 41(4), pp. 663-685. https://doi.org/10.1111/j.1468-0068.2007.00666.x
Polderman, T. J. C., Benyamin, B., de Leeuw, C. A., Sullivan, P. F., van Bochoven, A., Posthuma, D., & Boomsma, D. I. (2015). Meta-analysis of the heritability of human traits based on fifty years of twin studies. Nature Genetics, 47(7), 702–709. https://doi.org/10.1038/ng.3285
Strawson, G. (n.d.). Free will. The Information Philosopher. https://www.theinformationphilosopher.com/solutions/philosophers/strawsong/free_will.html
Wegner, D. M. (2002). The Illusion of Conscious Will. United Kingdom: Bradford Books.
