By merely observing the electrical activity in the brain, Libet could predict what a person would do before the person was actually aware of having decided to do it. This finding caused philosophers of mind to ask: If the choice is determined in the brain before we decide to act, where is free will?... choice in action, as in perception, may reflect the importance of unconscious inference. Libet proposes that... just before the action is initiated, consciousness is recruited to approve or veto the action.

In Search of Memory (2006)