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A Reader Asks: Does Neuroscience Disprove Free Will?

Materialists sometimes misrepresent the evidence for free will, especially Benjamin Libet’s work

Here’s the question:

I have a question regarding free will. Sam Harris in his interview with Dan Dennett said that “If we decide to do go to somewhere we experience it later but our brain decided it much earlier than our experience to this decision. If we scan the brain at that time we will tell you before you came to know” Now it raise a question because we decide through intellect. You said that free will is due to intellect so intellect is challenged here.

It’s an excellent question. The answer in brief is that we most certainly do have free will. We can see this from three perspectives: scientific, philosophical, and logical.

The scientific evidence

Mousetrap with a piece of cheese on a dark vintage background. The concept -"There's no such thing as a free lunch.

The scientific evidence for free will is most clearly seen in the research of Benjamin Libet, a pioneer in the study of decision-making. In his elegant experiments, he asked people to decide to push buttons and measured their brain waves while they made the decisions.

He found that there was a brain wave from the cortex about a half second before the person was aware of making the decision. Libet initially interpreted this as refuting free will — it seemed that our “decisions” are determined beforehand by physical processes in the brain and we merely experience the illusion of deciding freely.

But Libet was an excellent scientist so he tested the hypothesis that free will isn’t real by asking the volunteers to occasionally veto their decision after making it — to decide to push the button but to then immediately decide not to. He found that there was no brain wave associated with the veto — i.e., the veto was not from the brain. Thus, the veto was immaterial and independent of brain processes, and it corresponded to free will. Libet concluded that our decisions consist of two parts: a preconscious “temptation” and a conscious acceptance or veto. The temptation was associated with brain activity and might in that sense be considered involuntary (even that is problematic). But the acceptance or veto of the temptation was not determined by brain activity and appeared to be immaterial (i.e. spiritual) in origin. Libet quipped that he hadn’t proven free will per se, but he had proved “free won’t.”

Materialists like Harris misrepresent Libet’s work. It is hard to believe that they do not know they are doing so. Harris has a PhD in neuroscience and he’s fully aware of Libet’s research, yet he chooses to mislead the public about the fact that Libet’s work supports free will. It’s unscientific behavior on the part of a scientist and a public intellectual but this sort of thing is par for the course for materialists.

Libet’s research with vetoing decisions has not been tested by other researchers. Research that purports to show determinism to be true is invalid because the neurobiological correlates of vetoing a decision have not been studied since Libet. The current state of neuroscience is that free will is clearly supported by the science.

The philosophical perspective

The philosophical perspective is that (in my view) the most cogent model of the soul is that of Aristotle and Thomas Aquinas. In their model, called hylemorphic dualism, there are two types of mental states — sensitive and rational. Sensitive states are sensation, perception, imagination, memory, and sensitive appetites (emotions), among others. These are tightly linked to matter and may be considered material powers. Human beings also have rational mental states, which are the powers of the intellect and the will. These abstract powers are immaterial — they are not caused by matter — and thus the will is not determined by the brain.

The Aristotelian–Thomistic model fits Libet’s research very nicely — the material “temptation” comes from the sensitive material powers of the soul and the acceptance or veto comes from the immaterial will.

The logical view

The logical view is, from my perspective, the most compelling of all. It goes like this:

If your thoughts and actions are determined wholly by your brain, then they are determined by brain chemistry of various sorts — action potentials, chemical transmitters, etc. Potentials and chemicals behave according to the rules of physics and chemistry.

The claim that “free will is not real” is a proposition — it is an assertion of fact that may be true or false. A proposition invokes logic and inference. However, logic and inference are not physics and chemistry. That is, a particular state of the brain has no logical or inferential content. It has only physical and chemical content — quantum states, molecular structures, energy flow, etc. When philosophers argue, they use terms like modus ponens or modus tollens. But there’s no modus ponens or modus tollens in brain chemistry.

There is no overlap between physics and logic; therefore a purely physical brain state cannot be logical and cannot be a proposition. Thus, the brain state can have no truth value. So the assertion “free will is not real,” if based on physical determinism (which is Harris’ claim), is not really an assertion at all. It’s an electrical current or a secretion. It is not a proposition nor does it have any truth value.

If Harris’ brain really determined his actions and thoughts, Harris hasn’t really made any assertion at all. If free will isn’t real, we can make no valid claims of any sort. So, by denying free will, Harris denies his capacity to hold rational opinions. Meat robots don’t make “claims” worth paying attention to.


Harris and other materialists are wrong about the neuroscience of free will, wrong about the philosophical basis for free will, and they even logically refute their own claims.

Free will is real. It makes no sense (literally) to say otherwise. Neuroscience supports free will and it can be defended readily on a philosophical basis. Denial of free will logically denies the capacity to make any truth claim at all.

After all, only if our reasons and decisions are free from material determinism can we make meaningful propositions about truth that are worth paying attention to. The claim “free will is not real,” if it is true, is not an opinion, it’s merely a state of matter.

Only if we are not meat robots — only if we really do have free will — do our opinions matter.

You may also enjoy these articles by Michael Egnor on free will:

Why I, as a neurosurgeon, believe in free will. The spiritual aspect of the human soul, sadly, leaves its signature in epilepsy


Can physics prove there is no free will? No, but it can make physicists incoherent when they write about free will. Think of the irony: she entreats us “If you want to make good decisions…” after insisting that we can make no decisions at all, let along good ones.

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.

A Reader Asks: Does Neuroscience Disprove Free Will?