Why Free Will Is an Illusion (and Why It Doesn't Matter)

Most people live their lives believing they are the true authors of their choices. But what if free will doesn't exist - and never did?

As a functionalist, I believe that consciousness and decision-making are pure functions of physical processes. Free will is an illusion, born from the complexity of those processes, not some magical exception to causality.

In this post, I'll explain why, and show why justice, ethics, and accountability still matter even in a deterministic universe.

Why No Free Will?

There are various reasons for holding this belief, and enough material online that I won't cover the reasons in great detail but in short:

• Philosophical: You only do something if you want to, or if you are forced to. Obviously there's no freedom in being forced, and think about it - you can't actually control what you want!
• Neurological:
  • a) People lose their identities and certain functions due to brain injuries or medical procedures, showing that "who we are" is physically determined.
  • b) We can predict someone's movements/actions before they've consciously made the decision to perform them (such as moving a hand) by analysing brain activity. This suggests that actions and the perception of conscious choice are retrospective justifications entirely made up by the brain.
• The converse of the free will theorem.

The Paper Brain Thought Experiment

The idea of this thought experiment is that what if you could build a super powerful computer, scan someone's brain with enough fidelity down to every last elementary particle and ran it on a perfect simulation of the universe, would that simulated brain be conscious?

A functionalist answer to this thought experiment is: yes. Consciousness is a pure function of the system, which in our case is the universe. It depends entirely on the state and structure of the system, and thus can, in principle, be simulated.

Now there are some potential refutations of this claim, let's address them one by one:

• What if something metaphysical causes consciousness? If something metaphysical has causal effects in our universe, it is only "meta" because we don't yet understand how it works. As soon as we develop a physical model for it, it stops being "meta" and becomes just another part of physics. A "perfect simulation of the universe" would, by definition, capture all causal mechanisms, even those we currently label metaphysical. Therefore, if consciousness had any causal basis at all, it could be modeled in the simulation. Otherwise, it would be indistinguishable from a non-effect.
• But quantum mechanics says that the world indeterministic: Yes, but indeterminism does not give us free will - just the fact that the univserse isn't perfectly predictable. Beta decay is unpredictable as well, but does that mean radioactive atoms have free will?

Justice as a "Cost Function"

So if we live in a world without free will, does that mean that justice systems and accountability are useless? After all, if we no one really chooses their actions, how do we assign blame or punishment?

The answer lies in the realization that punishment acts as reinforcement - a deterrent - and not moral condemnation. Punishment is simply what naturally happens to offenders of a system in order to provide negative feedback, much like how a cost function operates in machine learning. An AI model's cost function doesn't hold the model morally accountable for getting something wrong, it simply nudges the model to "perform better" next time. Likewise, a system of law should aim to minimize harmful behavior by shaping incentives appropriately, not by seeking retribution.

Under this view, there are no questions of absolute "moral" right or wrong - only questions of what incentive structures best produce desired outcomes, like the flourishing and survival of conscious beings. Our concept of ethics simply maps to those incentive structures. Forgiveness and rehabilitation also arise naturally in such a system: for less serious offenses, they provide agents with a pathway to reintegrate and improve. Without forgiveness, once someone commits an offense, there is no longer an incentive to reform - reinforcing cycles of harm instead of breaking them. A system without forgiveness incentivizes evil to remain evil.

This simply means that accountability should be viewed as a pragmatic tool - a lever to optimize system behavior - not as a metaphysical judgment on souls.

Wrapping Up

In a world without free will, our actions are still shaped by the systems we inhabit, whether that's our brains, our societies, or the universe itself. Free will may be an illusion, but that doesn't diminish the importance of justice, ethics, or accountability - it only changes how we understand them.

A functionalist approach to morality shifts the focus from metaphysical blame to reinforcing behaviors that benefit the system, creating a more thoughtful, pragmatic way to view human actions. In this system, forgiveness and rehabilitation aren't just nice ideas, they're vital tools for reinforcing positive behavior and helping individuals improve.

Ultimately, whether or not we have free will, our ethical systems must adapt to what truly shapes us: our functions, our environments, and our collective incentives.