Does Contemporary Neuroscience Support or Challenge the Reality of Free Will?
August 28, 2012
“All the world’s a stage, and all the men and women merely players.”— Shakespeare
Humans love stories. We tell each other the stories of our lives, in which we are not merely players reading a script but also the authors. As authors we make choices that influence the plot and the other players on the stage. Free will can be understood as our capacities both to make choices—to write our own stories—and to carry them out on the world’s stage—to control our actions in light of our choices.
What would it mean to lack free will? It might mean we are merely puppets, our strings pulled by forces beyond our awareness and beyond our control. It might mean we are players who merely act out a script we do not author. Or perhaps we think we make up our stories, but in fact we do so only after we’ve already acted them out. The central image in each case is that we merely observe what happens, rather than making a difference to what happens.
How might neuroscience fit into the story I am telling? Most scientists who discuss free will say the story has an unhappy ending—that neuroscience shows free will to be an illusion. I call these scientists “willusionists.” (Willusionists include Sam Harris, Jerry Coyne, Jonathan Bargh, Daniel Wegner, John Dylan Haynes, and as suggested briefly in some of their work, Stephen Hawking and Richard Dawkins.) Willusionists say that neuroscience demonstrates that we are not the authors of our own stories but more like puppets whose actions are determined by brain events beyond our control. In his new book Free Will, Sam Harris says, “This [neuroscientific] understanding reveals you to be a biochemical puppet.” Jerry Coyne asserts in a USAToday column: “The ineluctable scientific conclusion is that although we feel that we’re characters in the play of our lives, rewriting our parts as we go along, in reality we’re puppets performing scripted parts written by the laws of physics.”
There are several ways willusionists reach their conclusion that we lack free will. The first begins by defining free will in a dubious way. Most willusionists’ assume that, by definition, free will requires a supernatural power of non-physical minds or souls: it’s only possible if we are somehow offstage, beyond the causal interactions of the natural world, yet also somehow able to pull the strings of our bodies nonetheless.(For example, Read Montague.) It’s a mysterious picture, and one that willusionists simply assert is the ordinary understanding of free will. Based on this definition of free will, they then conclude that neuroscience challenges free will, since it replaces a non-physical mind or soul with a physical brain.
But there is no reason to define free will as requiring this dualist picture. Among philosophers, very few develop theories of free will that conflict with a naturalistic understanding of the mind—free will requires choice and control, and for some philosophers, indeterminism, but it does not require dualism. Furthermore, studies on ordinary people’s understanding of free will show that, while many people believe we have souls, most do not believe that free will requires a non-physical soul. And when presented scenarios about persons whose decisions are fully caused by earlier events, or even fully predictable by brain events, most people respond that they still have free will and are morally responsible. These studies strongly suggest that what people primarily associate with free will and moral responsibility is the capacity to make conscious decisions and to control one’s actions in light of such decisions.
But willusionists also argue that neuroscience challenges free will by challenging this role for consciousness in decision-making and action. Research by Benjamin Libet, and more recently by neuroscientists such as John Dylan Haynes, suggests that activity in the brain regularly precedes behavior—no surprise there!—but also precedes our conscious awareness of making a decision to move. For instance, in one study neural activity measured by fMRI provided information about which of two buttons people would push up to 7-10 seconds before they were aware of deciding which to push.
If such early brain activity always completely determines what we do before our conscious thinking ever comes into the picture, then this would suggest we lack free will, because our conscious thinking would happen too late to influence what we did—an audience rather than author. But the data does not show that brain activity occurring prior to awarenesscompletely causes all of our decisions. In the study just described, the early brain activity correlates with behavior at only 10% above chance. It is not surprising that our brains prepare for action ahead of time and that this provides some information about what people will do…