Free Will in an Age of Neuroscience

In 1983, Benjamin Libet published a finding that shook the philosophical establishment. Using EEG and a clock task, he showed that a specific pattern of brain activity — the readiness potential — began roughly 550 milliseconds before a subjects reported awareness of their intention to move. The brain, it seemed, had already decided before the person knew they had decided.

The implications were provocative. If the brain initiates action before consciousness is aware of it, then conscious will is not the cause of our behaviour — it is, at best, a late-arriving commentator.

The Standard Interpretation

The standard reading of Libet’s experiment goes like this: unconscious neural processes prepare the movement, conscious awareness of the intention follows, and then the action occurs. Free will, on this picture, is an afterthought — a story we tell ourselves about decisions that have already been made.

This interpretation attracted strong responses. Daniel Wegner argued that the feeling of will is an illusion, a post-hoc construction that our brains impose on actions they have already initiated. Sam Harris picked up the thread and argued that free will is simply incoherent — that no account of causation leaves room for a self that stands outside the causal order and chooses.

The Complications

The story is more complicated than the standard interpretation suggests.

For one thing, the readiness potential may not reflect a decision at all. Recent work by Schurger, Sitt, and Dehaene suggests that the readinesspotential is better understood as a fluctuation in neural noise that crosses a threshold — not a decision being prepared, but a stochastic process being detected.

For another, the act of flexing a wrist in a laboratory is not the kind of decision that raises deep questions about free will. Choosing a career, deciding whom to marry, forming a moral judgment — these involve deliberation, reasons, and self-reflective evaluation in a way that spontaneous wrist flexing does not.

A More Nuanced Picture

I think the neuroscience tells us something important: that the boundary between conscious and unconscious processing is blurrier than folk psychology assumes. Much of what we do is initiated below the threshold of awareness.

But this does not show that free will is illusory. It shows that free will, if it exists, is not the kind of thing that happens in a single moment of conscious choice. It is a pattern — a pattern of reflective endorsement, of acting in ways that cohere with one’s values and long-term commitments, of being responsive to reasons.

This is not the libertarian free will of philosophical tradition. But it may be the only free will worth wanting.