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Hands of a man tearing a piece of paper with inscription free will
Hands of a man tearing a piece of paper with inscription free will

Neuroscience Can Help Us Understand Why Free Will Is Real

Physicist Sabine Hossenfelder and biologist Jerry Coyne, who deny free will, don’t seem to understand the neuroscience

Evolutionary biologist Jerry Coyne seems obsessed with denying free will. In a recent post on his blog, Why Evolution Is True, he supported the claim of theoretical physicist Sabine Hossenfelder that we do not have free will:

If you’ve read this site, you’ll know that my own views are pretty much the same as hers, at least about free will. We don’t have it, and the fundamental indeterminacy of quantum mechanics doesn’t give it to us either.

Hossenfelder doesn’t pull any punches:

“This means in a nutshell that the whole story of the universe in every single detail was determined already at the big bang. We are just watching it play out.”…


Jerry Coyne, “Sabine Hossenfelder says we don’t have free will, but its nonexistence shouldn’t bother us” at Why Evolution Is True

Both Coyne and Hossenfelder are atheists, materialists, and determinists—a sort of intellectual dark triad—and their beliefs are scientifically and logically uninformed. They use denial of free will to prop up their materialist and determinist irreligion. It is not science; it is an ideological project, without a shred of science or logic to back it up.

There are three lines of evidence supporting the reality of free will: Neuroscience, physics and philosophy all point to the fact that free will is real. In this post, I’ll discuss the neuroscience. But first, we must start by understanding what free will is. Erroneous definition of free will is at the root of many mistakes inherent in denying it.

It turns out that free will is rather hard to define rigorously, if taken all by itself. Many have tried. Definitions such as “choice that is uncaused,” “choice that is an inclination that originates wholly within an organism,” and “choice that entails the existence of alternative possibilities” have been proposed. Each is inadequate to the situation.

The definition of free will really depends on the definition of will. Will is a subset of appetite (an Aristotelian term), which means an inclination to act. There are two kinds of appetite—sensitive appetite and rational appetite. Sensitive appetites are appetites that arise from concrete perceptions and imagination. I perceive a piece of cake, and I imagine how wonderful it would taste, so (if I am impulsive) I eat it.

Chocolate cake with fresh strawberries

Rational appetite is inclination to act based on reason, not on perceptions or imagination. Suppose, for example, that I am on a diet. My decision about whether to eat a piece of cake because of its appearance and how I imagine it will taste is fundamentally different from my decision about whether I will break my diet in order to do so. One inclination—my sensitive appetite—is based on concrete perception. The other inclination—to follow my diet—is based on abstract reason.

Only abstract reason/rational appetite is the will part of free will. Sensitive appetite is not part of the will—it is a passion based wholly on material factors—my brain chemistry, etc. Sensitive appetite is not free—this kind of appetite is indeed dictated by my molecules and neurotransmitters. I can condition it and override it but in itself, it is wholly material and subject to the laws of nature.

My will—my rational appetite—is an immaterial power of my mind. My will can be influenced by my passions but it is inherently free of material determinism of any kind. For example, my decision whether or not to eat that piece of cake is the result of the struggle between my material passions and my immaterial will—between my sensitive and my rational appetite. Sometimes my passion wins. Sometimes my reason—my will—wins.

Now that we have a satisfactory definition of will, what do we mean by free will? Philosopher and theologian Thomas Aquinas gave the best answer: My free will is inclination based on abstract reasoning that arises wholly from me. Nothing other than me determines my will. I determine my will and my will is an immaterial power of my soul. In this specific sense, I have free will.

Now let’s get to the neuroscience. Neuroscience has a lot to contribute to the debate over free will and all of it supports the reality of free will. There isn’t a shred of neuroscientific evidence that contradicts the reality of free will.

Two major types of experiments address the question of free will:

The first is the experiments of Benjamin Libet, a mid- to late 20th century neuroscientist who studied the precise timing of electrical activity in the brain and conscious decisions to do simple tasks such pushing a button. Libet found that we have pre-conscious impulses characterized by spikes in brain waves that precede conscious decisions by about a half-second. But he also found that these pre-conscious impulses (which are not freely generated) are merely temptations. We retain the power to accept or reject them, and acceptance or rejection of these temptations is not accompanied by brain waves. Libet called this state “free won’t”: We are bombarded by temptations that are beyond our immediate control but we have the immaterial freedom to accept or reject them. He noted the congruence between his experimental results and the traditional Jewish and Christian understanding of sin. We are tempted involuntarily but we always have freedom to comply with or reject temptation.

The second set of experiments is, in my view, even more compelling. They derive from the work of Wilder Penfield, the pioneer in the neurosurgery of epilepsy in the mid-20th century. Penfield performed over a thousand “awake” brain operations on patients with epilepsy. He stimulated their brains and the recorded the effect of stimulation on these awake patients. He found that he was able to stimulate practically any concrete mental phenomenon—movement of limbs, perceptions of light or smell or tactile sensations, emotions, memories—but he was never able to stimulate abstract thought or free will. In his memoir, Mystery of the Mind, he concluded that abstract thought and free will (which he called ‘the mind’ as distinct from automatic responses like perceptions, movements, or emotions) did not originate in the brain, but were immaterial powers of the soul. He began his career as a strict materialist but ended his career as a convinced dualist.

He also noted a remarkable fact: there are no intellectual seizures, and by implication, no seizures that invoke free will. There are no calculus seizures, no logic seizures, no seizures that make the patients think abstractly or will (apparently) freely. There are no seizures that make you choose to be a Republican or a Democrat, no seizures that make you Christian or Jewish, no seizures that make you apply certain kinds of logic to a problem rather than another kind of logic. This is remarkable: if the will is merely the product of brain activity, at least some seizures should evoke will. They never do. Many seizures do feature complex manifestations (they’re called complex partial seizures), but these complex seizures always involve concrete thoughts and actions —perceptions, emotions, and stereotypic movements. There are no seizures that invoke abstract thought or abstract decisions—there are no free will seizures.

This remains true to this day. There are no reports in the medical literature—despite literally billons of seizures suffered by patients in the modern era—of any seizure that replicates free will. This remarkable fact—literally based on billions of data points—clearly shows that the will is not determined by the material state of the brain. If the will were determined by neural activity, the will—abstract choice based on reason—would at least occasionally be replicated by seizures. It never is.

Coyne, Hossenfelder and other free will deniers are ignorant of the mountain of neuroscience evidence confirming free will. They are also ignorant of the philosophical reasoning supporting free will and of the evidence in physics that refutes determinism (but these are both subjects for another post).

If Dr. Coyne reads this far in this post, I challenge him: If free will is determined by brain states, show us the medical or neuroscience evidence that free will is ever evoked by seizure or by neurosurgical stimulation of the brain. In other words, Dr. Coyne, show me the neuroscience behind your bizarre denial of free will.

Neurosurgeon Michael Egnor has written a fair bit on free will for Mind Matters News. Here are some selections to consider:

No free will means no justice: “Free will is the cornerstone of all human rights and the cornerstone of our Constitutional rights. The denial of free will is, literally, the denial of human freedom. Without free will, we are livestock, without the presumption of innocence, without actual innocence, and without rights. A justice system that has no respect for free will—a justice system in which human choices are diseases— is a system of livestock management applied to homo sapiens.”


Jerry Coyne just can’t give up denying free will. Coyne’s denial of free will, based on determinism, is science denial and junk metaphysics

How Libet’s free will research is misrepresented: Sometimes, says Michael Egnor, misrepresentation may be deliberate because Libet’s work doesn’t support a materialist perspective.

Does “alien hand syndrome” show that we don’t really have free will? One woman’s left hand seemed to have a mind of its own. Did it?


Does brain stimulation research challenge free will? If we can be forced to want something, is the will still free?

Michael Egnor

Senior Fellow, Center for Natural & Artificial Intelligence
Michael R. Egnor, MD, is a Professor of Neurosurgery and Pediatrics at State University of New York, Stony Brook, has served as the Director of Pediatric Neurosurgery, and award-winning brain surgeon. He was named one of New York’s best doctors by the New York Magazine in 2005. He received his medical education at Columbia University College of Physicians and Surgeons and completed his residency at Jackson Memorial Hospital. His research on hydrocephalus has been published in journals including Journal of Neurosurgery, Pediatrics, and Cerebrospinal Fluid Research. He is on the Scientific Advisory Board of the Hydrocephalus Association in the United States and has lectured extensively throughout the United States and Europe.

Neuroscience Can Help Us Understand Why Free Will Is Real