Florida, born 1951

Alfred Mele

The headlines say that neuroscience has shown free will to be an illusion. Look closely at the experiments, and they show nothing of the kind. What they measure may be an urge, not a decision, and the task they study is picking, not choosing.

The view

Mele, a philosopher at Florida State University, has written widely on self-control, weakness of will and intention. From 2010 to 2013 he led a large research project, Big Questions in Free Will, which brought philosophers and scientists together to test claims about free will. His short book Free: Why Science Hasn't Disproved Free Will (2014) sums up the result for general readers.

Unusually, Mele is officially neutral about the metaphysics. He has defended both a compatibilist and a modest libertarian account, without committing to either. His target is narrower and more practical: the claim, made by some scientists and repeated in the press, that experiments have already shown free will to be an illusion.

The argument

The early brain activity in Libet's experiments may reflect a growing urge to move, not a decision to move. After Mele, Effective Intentions (2009)

In Libet's experiments, people flexed a wrist whenever they felt like it, and reported when they first felt the urge. Brain activity began about half a second before the movement, and a third of a second before the reported urge. Mele raises three problems. First, nothing shows that the early activity is a decision; it may be a build-up of readiness that sometimes ends in a decision and sometimes does not. Second, people are poor at timing their own mental events to a fraction of a second. Third, the task is arbitrary picking, with no reasons on either side. Nothing follows about choices that matter, such as whether to take a job, made after deliberation.

Later work strengthened the first point. In 2012 Aaron Schurger and colleagues proposed that the readiness potential is what you get when you average random fluctuations in brain activity backwards from the moment they happen to cross a threshold. Run the trials below and then average them.

The averaged curve rises slowly for a long time before the movement, just as the readiness potential does. Yet no trace "decided" anything early: each crossing was decided by noise in the last moments. If this model is right, the famous half-second shows only that the brain was drifting towards readiness, not that the outcome was fixed.

Where he meets Dennett

On the science they agree almost completely. Dennett also argued that Libet's conclusion depends on a mistaken picture: a single moment, at a single place in the brain, when a decision becomes conscious. Both think the free will deniers have overreached, and both think that deliberate, reason-driven choices are the ones that matter for responsibility, not the twitch of a wrist.

Where they part

Mele keeps the metaphysical question open, and has spent time showing how a libertarian might make sense of their view. Dennett thought the libertarian's indeterminism was idle, and that the case for compatibilism was settled. Mele's approach is also more piecemeal and experimental: he examines one study at a time and asks what it really shows. Dennett's is more sweeping, rooted in a whole theory of consciousness that predicts in advance what such experiments can and cannot reveal.

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Further reading

• Alfred R. Mele, Free: Why Science Hasn't Disproved Free Will (Oxford, 2014).
• Alfred R. Mele, Effective Intentions: The Power of Conscious Will (Oxford, 2009).
• Aaron Schurger, Jacobo D. Sitt and Stanislas Dehaene, "An accumulator model for spontaneous neural activity prior to self-initiated movement", PNAS 109 (2012).