Compatibilism: Philosophy’s Favorite Answer to the Free Will Debate

Compatibilism: Philosophy’s Favorite Answer to the Free Will Debate

Popular claims that free will is an illusion tend to miss that, within philosophy, the debate hinges not on whether determinism is true, but on whether determinism and free will are compatible — and most philosophers working today think they are.

Jack Maden
By Jack Maden  |  May 2024


This morning I drank coffee rather than tea. Why? I don’t know — I just fancied a cup of coffee, so I made one. This might seem innocent enough; but, if you gave them the chance, philosophers could scrawl hundreds of thousands of words about my choice of coffee over tea.

Some of them — a smaller group in philosophy, but a growing one in neuroscience and popular culture — would say that, actually, any choice I felt was an illusion.

Unbeknown to my sleepy self, psycho-biological chains of causality converged in my brain to fix my choice of coffee in place.

My feeling of free will was thus nothing more than that: a feeling. My conscious ‘choice’ was an aftereffect, playing no real part in producing my cup of coffee… any freedom I felt was illusory…

The view that free will is an illusion is increasingly infiltrating the mainstream. Neuroscientist Sam Harris makes the case in his popular 2012 book, Free Will, as does neuroscientist Robert Sapolsky in his 2023 book, Determined: Life Without Free Will.

(In case you’re not familiar with them, I cover Harris’s arguments for free will being an illusion here).

Persuasive as they may be, however, advances in neuroscience and brain research simply bring into sharp focus what has long been a problem for free will: that we are embodied beings living a physical world seemingly determined by cause and effect.

As the Roman philosopher Lucretius asked 2,000 years ago in his epic poem On The Nature of Things, for instance:

If atoms never swerve and make beginning
Of motions that can break the bonds of fate
And foil the infinite chain of cause and effect
What is the origin of this free will
Possessed by living creatures throughout the earth?

What indeed? How is free will possible in a physically determined cosmos?

The increasingly popular answer is that, well, it’s not: determinism and free will are irreconcilable, incompatible.

The past controls the present and the future. We cannot control the past. So, we cannot control the present or the future.

Despite the growing popularity of this kind of view, however, a 2020 Philpapers survey revealed that only 11% of philosophy professors agree with it.

The survey included thousands of philosophy professors from across the globe, many of whom have contributed to the rich philosophical literature around free will and thought deeply about the subject for decades.

So, what’s going on?

Are philosophers simply not caught up on the latest neuroscience?

Do they think things somehow aren’t determined by their preconditions?

Or is there some nuance to the free will discussion that’s being missed?

Compatibilism: determinism and free will are compatible with each other

The vast majority of the philosophers surveyed by Philpapers align themselves to a position known as ‘compatibilism’, which challenges the assumption that human freedom and determinism are mutually exclusive.

In other words, Harris and Sapolsky spend a lot of time persuading us that causal determinism is true, because they think if they can do so, then free will is automatically ruled out.

They are thus incompatibilists about free will: they think causal determinism and human freedom are irreconcilable.

Much of the popular discourse around free will also assumes this incompatibilist position: if the cosmos is causally determined, the story goes, then humans are mere biological automata, carrying out in each moment what they cannot help but do for reasons they cannot help but be moved by.

But what if this assumption, that determinism and free will are incompatible, is not the case?

What if the status of the freedom and responsibility we feel in our actions is not actually tied to whether the fundamental nature of the universe turns out to be determined or undetermined?

What if our understanding of the ‘free’ part of ‘free will’ is seriously underdeveloped?

What does freedom really mean?

Compatibilism can be confusing, and there are different strands to compatibilist thought, but the general thrust of the compatibilist position is that incompatibilists like Harris and Sapolsky are far too strict in their definition and understanding of freedom.

In fact, as the philosopher John Martin Fischer points out in his rather scathing review of Sapolsky’s Determined, ‘free will’ is often not explicitly defined at all in the popular discourse around the subject.

Rather than interrogate what free will might even reasonably mean for embodied beings in a physical universe, people often use the term without thinking about it.

Accordingly, the popular conception of ‘free will’ tends to rest on the standard incompatibilist understanding of free will, which is something like, ‘we are the conscious authors of our actions and can choose what to do at any moment’.

Incompatibilists think determinism effectively rules out this popular conception of free will.

But compatibilists want us to look at this conception of free will a little more closely. Once we do so, we recognize that it generally rests on two requirements:

  1. In order to be free, the original causal source of our actions must reside in consciousness
  2. In order to be free, we must have the ability to do otherwise in identical situations

While these requirements may appear fairly reasonable on the surface, many compatibilists think they set an absurdly high bar for freedom.

Take the first one, for example: that, in order to be free, the original causal source of our actions must reside in consciousness.

Compatibilists might ask: why is this a condition of freedom? Why does it matter if my will originally forms in consciousness or not? Over the course of my lifetime, of course my behavior has been produced by all sorts of things outside of my conscious awareness and control…

Does freedom for the incompatibilist require that I have no background preferences? That I possess no characteristic set of wants, desires, and motives? That I never subconsciously scratch an itch? That I must consciously choose to digest my food? That I become immune to my biology and history and spontaneously reinvent myself and my behavior in consciousness, moment to moment?

As the late philosopher Daniel Dennett puts it in his (also scathing) review of Harris’s Free Will:

I don’t always have to reflect, consciously, on my reasons for my intentions for them to be both mine and free. When I say ‘thank you’ to somebody who gives me something, it is ‘force of habit’ and I am entirely unaware of the events in my brain that cause me to say it — but it is nonetheless a good example of a free action. Had I had a reason to override the habit, I would have overridden it. My not doing so tacitly endorses it as an action of mine. Most of the intentions we frame are like this, to one degree or another: we ‘instinctively’ reach out and pull the pedestrian to safety without time for thinking; we rashly adopt a sarcastic tone when replying to the police officer, we hear the doorbell and jump up to see who’s there. These are all voluntary actions for which we are normally held responsible if anything hinges on them.

Compatibilists can also question the second implicit requirement of the popular conception of free will: that, in order to be free, we must have the ability to do otherwise in identical situations.

But doing otherwise in identical situations is impossible, compatibilists might protest.

If everything was exactly the same, obviously we’d act in exactly the same way. Why wouldn’t we? We’d be operating with exactly the same desires, preferences, and information…

Wouldn’t a more reasonable interpretation of the ‘ability to do otherwise’ be that we are able to do so in similar situations? I.e. ‘if I could go back in time, I would act differently, knowing what I do now…’

Many compatibilists thus think that the popular conception of free will — the standard incompatibilist understanding of free will — defines freedom in such a way that no corporeal being could possibly ever have it.

Indeed, ‘free will’ for the incompatibilist requires us to be God-like, immune to our histories, able to step outside the laws of nature and create new preferences and desires from moment to moment.

Obviously we don’t possess this God-like level of freedom, compatibilists think — but isn’t it a bit unreasonable to have an initial definition of free will so extreme that it requires us to literally break the laws of physics merely to regard ourselves as ‘free’?

We don’t think of ourselves as enslaved by, say, gravity, so why see ourselves as slaves to causality?

Why does the rather basic recognition that we are part of causal chains larger than ourselves suddenly entail we have to rid ourselves of all feelings of agency and moral responsibility?

A compatibilist understanding of freedom

What might freedom mean, then, for a compatibilist? An early classical definition, not without its own problems, is the ‘ability to fulfill one’s preferences without impediment’.

This can be developed in various ways, but free will in this sense can generally be understood as the ability of rational agents to act in accordance with their reasons and preferences, whereby a rational agent is defined as someone capable of responding to reason (so, young children don’t have free will, but most healthy adults do).

Yes, we might not be able to consciously choose our background preferences and desires, we cannot always control our responsiveness to reason, we cannot create our deepest wants and needs, and a great deal of our behavior is subconscious…

But as long as most of the time we can freely exercise our wills, as long as our actions align with our desires, as long as we can do what we want to do as rational agents… then isn’t this all the freedom we need?

There is nothing about causal determinism, says the compatibilist, that stops us from freely playing out our parts as causal agents in the vastly complex causal system…

Forced, or free?

To really bring out the difference between the compatibilist and incompatibilist conceptions of freedom, recall once again my choice this morning between coffee and tea, and consider these two scenarios:

  1. I decide to have coffee because I want to have coffee
  2. I decide to have tea because someone puts a gun to my head and says they will pull the trigger if I don’t pick tea

For the incompatibilist, in terms of the freedom of my decision, there is no real difference between these cases.

While my conscious feelings in each case would certainly differ, ultimately I am either forced by the gunman, or forced by my preferences…

But the compatibilist thinks this is far too extreme a conception of ‘freedom’. Obviously there is a difference in the freedom of my decision between the two cases.

Yes, in the first case, my preference for coffee simply arose for me unbidden, no doubt due to psycho-biological causes I have no idea about — but I freely, happily acted upon it, and had no reason not to...

In the second case, however, there is a clear impediment to my ‘free will’...

And it is precisely in this softer, more nuanced, compatibilist conception of freedom, says Dennett, that we find the ‘elbow room’ needed to secure things like moral and artistic responsibility as we usually understand them. He writes:

In the end, if we trace back far enough to our infancy or beyond, we arrive at conditions that we were just lucky (or unlucky) to be born with. This undeniable fact is not the disqualifier of responsibility that [incompatibilists] assume. It disqualifies us for ‘Ultimate’ responsibility, which would require us to be — like God! — causa sui, the original cause of ourselves... but this is nonsense. Our lack of Ultimate responsibility is not a moral blemish....

“Any realistic, reasonable account of free will,” Dennett continues,

acknowledges that we are stuck with some of our desires: for food and comfort and love and absence of pain — and the freedom to do what we want. We can’t not want these... they are the healthy, normal, sound, wise desires on which all others must rest. So banish the fantasy of any account of free will that is screwed so tight it demands that we aren’t free unless all our desires and meta-desires and meta-meta-desires are optional, choosable. Such ‘perfect’ freedom is, of course, an incoherent idea.

Determinism is the beginning of the discussion around free will, not its end

Incompatibilists might accuse compatibilists of simply moving the goal posts here, seeking to salvage free will merely by redefining it — conflating freedom of action with freedom of will. Their new definition doesn’t change the fact that determinism ultimately means we have no conscious control over our actions or desires…

But compatibilists might respond that the incompatibilist position relies upon a mystical, dualistic, erroneous conception of self, whereby ‘I’ am somehow separate from the processes in my brain and body…

The point for many philosophers is that determinism marks the beginning of the discussion around free will and moral responsibility, not its end.

Popular discourse around the subject tends to assume the incompatibilist definition of freedom, and thus makes the free will debate one of determinism vs. indeterminism.

Accordingly, neuroscientists like Harris and Sapolsky think presenting more evidence for causal determinism advances the free will debate.

The real meat of the discussion in philosophy, however, centers around compatibilism vs. incompatibilism. I have barely scratched the surface in this short article, but a vast philosophical literature discusses what freedom can even mean for non-God-like beings in a causally determined world.

For anyone interested in garnering a rich understanding of the nuances around the free will debate, then, compatibilism cannot be ignored.

What do you make of compatibilism and the free will debate?

  • Do you think determinism rules out free will?
  • Does the compatibilist view offer a more reasonable account of freedom?
  • Or, ultimately, can the free will debate not advance until we have a better understanding of the relationship between consciousness and the brain, and more refined understandings of both ‘freedom’ and ‘will’?

Explore further philosophical discussions of free will

If you’re interested in reading more about free will, determinism, and compatibilism, you might enjoy the free will chapter of my Life’s Big Questions course, which further covers the competing views of major thinkers. You’ll join me and course members discussing these ideas, along with other great questions of philosophy, inside.

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About the Author

Jack Maden

Jack MadenFounder
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Having received great value from studying philosophy for 15+ years (picking up a master’s degree along the way), I founded Philosophy Break in 2018 as an online social enterprise dedicated to making the subject’s wisdom accessible to all. Learn more about me and the project here.

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