Had participants’ brains already made the decision? Was the feeling of choosing just an illusion? Controversy has raged ever since. There is far more to the discussion about neuroscience and free will than this one experiment, but its simplicity has allowed it to capture the imagination of many who think our status as biological creatures limits our free will, as well as those who argue that free will survives the challenge of our minds being firmly grounded in our biological brains.

Part of the appeal of the Libet experiment is due to two pervasive intuitions we have about the mind. Without these intuitions the experiment doesn’t seem so surprising.

The first intuition is the feeling that our minds are a separate thing from our physical selves – a natural dualism that pushes us to believe that the mind is a pure, abstract place, free from biological constraints. A moment’s thought about the last time you were grumpy because you were hungry shatters this illusion, but I’d argue that it is still a persistent theme in our thinking. Why else would we be the least surprised that it is possible to find neural correlates of mental events? If we really believed, in our heart of hearts, that the mind is based in the brain, then we would know that every mental change must have a corresponding change in the brain.

The second pervasive intuition, which makes us surprised by the Libet experiment, is the belief that we know our own minds. This is the belief that our subjective experience of making decisions is an accurate report of how that decision is made. The mind is like a machine – as long as it runs right, we are happily ignorant of how it works. It is only when mistakes or contradictions arise that we’re drawn to look under the hood: Why didn’t I notice that exit? How could I forget that person’s name? Why does the feeling of deciding come after the brain changes associated with decision making?