Free Will for the Neuroscientist

1. Conscious and Unconscious Processes

In recent years, neuroscience has uncovered the role of unconscious processes in human decision-making. To some, conscious awareness has been relegated to an after-the-fact “interpreter” [1] of decisions that were already made by processes beneath awareness. These are usually demonstrated with very simple tasks like those in Benjamin Libet’s experiments.

In contrast, consider the common scenario of a student studying for tomorrow’s exam. She consciously chooses to study, rather than doing other things. Motivated by this conscious intent she reviews the material in her textbook and her lecture notes. As she studies, the neural pathways related to that information are strengthened, priming her brain to recall those facts as she reads the questions on tomorrow’s test. This is an example of “top-down” causation, where a consciously chosen intent (“I will study tonight”) results in physical modifications to her neural infrastructure.

2. The Reality Model, Rational Causation, and Me

Neuroscience studies the physical processes within the brain that bring about the mental events that we experience as thoughts and feelings. The brain organizes sensory data into a conceptually rich model of reality consisting of objects and events. With that model we can imagine possible futures that we might actualize through specific actions.

For example: It’s morning and I’m hungry. I can fix eggs for breakfast. But I can also fix waffles. Which will I choose? Well, I had eggs yesterday morning, and the day before that as well. The waffles seem more appealing this morning. So, I decide to fix waffles.

Having chosen what I will do, my conscious intent motivates and directs my subsequent actions. I get the ingredients together, heat up the waffle iron, and prepare waffles for breakfast. This is a deliberate act on my part. And the most meaningful cause was my process of deliberation and choosing.

Neuroscience aspires to describe the neural mechanisms by which such decisions are made. What parts are tracked by awareness? What other parts operate below the surface? However, one thing that neuroscience cannot do is suggest that something other than that brain, through those processes, is doing the choosing. And, if that brain happens to be my own, then that which is doing the choosing happens to be me.

3. Free Will

There are two distinct definitions of free will. The first is the operational definition, the one that most people understand and correctly apply to practical scenarios. Operational free will is a choice we make for ourselves that is free of coercion, such as a gun pointed at our head, and other forms of undue influence, such as a significant mental illness that creates hallucinations, impairs rational thought, or imposes an irresistible impulse. You’ll probably recognize these right away as issues related to holding someone legally responsible for their actions.

The operational definition requires nothing supernatural and makes no claims to being uncaused. Operational free will is not a subjective feeling, but an empirical distinction based upon objective evidence.

The second definition of free will is the “philosophical” definition. In philosophy, there is the notion of a choice that is made “free of causal necessity/inevitability”. The problem with this definition is that it creates a logical paradox. “Causal necessity” is logically derived from the presumption of perfectly reliable cause and effect. Each cause is itself an effect of prior causes. This “chain of causation” goes back as far as anyone can imagine, usually stopping (for convenience) at the Big Bang. So, freedom from causal necessity logically implies freedom from reliable cause and effect.

There are two problems with this notion. The first is that reliable cause and effect is necessary for freedom. Freedom is the ability to do what we want, and we can do nothing at all without reliable cause and effect. So the notion creates a paradox: how can someone, who is free of reliable cause and effect, reliably cause any effect? They can’t! Thus, the notion of “freedom from reliable cause and effect” is absurd.

The second problem with the philosophical definition is the delusion that “causal necessity/inevitability” is something that we need to be free of. Advocates of this notion describe it as some entity or force that robs us of control over our choices and actions, some kind of puppet master pulling our strings, or the driver of a bus where we are only passive passengers. This is all superstitious nonsense, of course. What we will inevitably do is exactly identical to us just being us, doing what we do, and choosing what we choose. And that is not a meaningful constraint upon our freedom.

Only a specific cause, such as a guy holding a gun to our head, can coerce us to act against our will, forcing us to submit our will to his. Causal necessity is not a guy with a gun. It is the ordinary cause and effect that we all take for granted and put to good use whenever we choose to do something.

4. Cleaning up the Mess

The solution is to discard the philosophical definition of free will, and return to the operational definition. The operational definition is understood by nearly everyone, at least until they attend a philosophy class or pick up one of the pop culture books that infects them with the paradox. Philosophy professors should relegate the determinism “versus” free will paradox to the section of their curriculum that studies paradoxes. It belongs with those created by Zeno and others. And they should equip their students with the skills to untangle these paradoxes by identifying their underlying hoax.


For more details on the free will paradox, see “Free Will: What’s Wrong and How to Fix It“.

  1. Gazzaniga, Michael S.. Who’s in Charge?: Free Will and the Science of the Brain (p. 75). HarperCollins. Kindle Edition.