Do we have free will? It is an age-old question which has attracted the attention of philosophers, theologians, lawyers and political theorists. Now it is attracting the attention of neuroscience, explains Michael S. Gazzaniga, director of the SAGE Center for the Study of the Mind at the University of California, Santa Barbara, and author of the new book, “Who’s In Charge: Free Will and the Science of the Brain.” He spoke with Mind Matters editor Gareth Cook.

Cook: Why did you decide to tackle the question of free will?

Gazzaniga: I think the issue is on every thinking person’s mind. I can remember wondering about it 50 years ago when I was a student at Dartmouth. At that time, the issue was raw and simply stated. Physics and chemistry were king and while all of us were too young to shave, we saw the implications. For me, those were back in the days when I went to Church every Sunday, and sometimes on Monday if I had an exam coming up!

Now, after 50 years of studying the brain, listening to philosophers, and most recently being slowly educated about the law, the issue is back on my front burner. The question of whether we are responsible for our actions -- or robots that respond automatically -- has been around a long time but until recently the great scholars who spoke out on the issue didn’t know modern science with its deep knowledge and implications.

Cook: What makes you think that neuroscience can shed any light on what has long been a philosophical question?

Gazzaniga: Philosophers are the best at articulating the nature of a problem before anybody knows anything empirical. The modern philosophers of mind now seize on neuroscience and cognitive science to help illuminate age old questions and to this day are frequently ahead of the pack. Among other skills, they have time to think! The laboratory scientist is consumed with experimental details, analyzing data, and frequently does not have the time to place a scientific finding into a larger landscape. It is a constant tension.

Having said that, philosophers can’t have all the fun. Faced with the nature of biologic mechanisms morning, noon, and night, neuroscientists can’t help but think about such questions as the nature of “freedom of action in a mechanistic universe” as one great neuroscientist put it years ago. At a minimum, neuroscience directs one’s attention to the question of how does action come about.

Cook: Do you think that neuroscience, as a field, needs to tackle these questions? That is, do you consider free will an important scientific question?

Gazzaniga: We all need to understand more about free will, or more wisely put, the nature of action. Neuroscience is one highly relevant discipline to this issue. Whatever your beliefs about free will, everyone feels like they have it, even those who dispute that it exists. What neuroscience has been showing us, however, is that it all works differently than how we feel it must work. For instance, neuroscientific experiments indicate that human decisions for action are made before the individual is consciously aware of them. Instead of this finding answering the age-old question of whether the brain decides before the mind decides, it makes us wonder if that is even the way to think about how the brain works. Research is focused on many aspects of decision making and actions, such as where in the brain decisions to act are formed and executed, how a bunch of interacting neurons becomes a moral agent, and even how one’s beliefs about whether they have free will affect their actions. The list of issues where neuroscience will weigh in is endless.

Cook: Please explain what you mean by the idea of an "emergent mind," and the distinction you draw between this and the brain?

Gazzaniga: Leibnitz raised the question almost 300 years ago with his analogy of the mill. Imagine that you can blow the mill up in size such that all components are magnified and you can walk among them. All you find are individual mechanical components, a wheel here, a spindle there. By looking at the parts of the mill you cannot deduce its function. The physical brain can also be broken into parts and their interactions examined. We now understand neurons and how they fire and a bit about neurotransmitters and so forth. But somehow the mental properties are indivisible and can’t be described in terms of neuronal firings. They need to be understood in another vocabulary.

This is sometimes called the emergent mind. Emergence as a concept in general is widely accepted in physics, chemistry, biology, sociology, you name it. Neuroscientists, however, have a hard time with it because they are suspicious that this concept is sneaking a ghost into the machine. That is not it at all. The motivation for this suggestion is to conceptualize the actual architecture of the layered brain/mind interaction so it can be properly studied. It is lazy to stay locked into one layer of analysis and to dismiss the other.

Cook: How does the mind constrain the brain?

Gazzaniga: No one said this is going to be easy and here is where the going gets tough. Picking up on the last thought the idea: we are dealing with a layered system, and each layer has its own laws and protocols, just like in physics where Newton’s Laws apply to one layer of physics and quantum mechanics to another. Think of hardware-software layers. Hardware is useless without software and software is useless without hardware.

How are we to capture an understanding how the two layers interact? For now, no one really captures that reality and certainly no one has yet captured how mental states interact with the neurons that produce them. Yet we know the top mental layers and the layers beneath it, which produce it, interact. Patients suffering from depression can be aided by talk therapy (top-down). They can also be aided by pharmacological drugs (bottom up). When these two therapies are combined the therapy is even better. That is an example of the mind constraining the brain.

Cook: And how does this idea of the mind and brain interacting bring you to your position on free will?

Gazzaniga: For me, it captures the fact that we are trying to understand a layered system. One becomes cognizant there is a system on top of the personal mind/brain layers which is yet another layer--the social world. It interacts massively with our mental processes and vice versa. In many ways we humans, in achieving our robustness, have uploaded many of our critical needs to the social system around us so that the stuff we invent can survive our own fragile and vulnerable lives.

Cook: You talk about “abandoning” the idea of free will. Can you explain what you mean by this, and how you came to this conclusion?

Gazzaniga: As I see it, this is the way to think about it: If you were a Martian landing on Earth today and were gathering information how humans work, the idea of free will as commonly understood in folk psychology would not come up. The Martian would learn humans had learned about physics and chemistry and causation in the standard sense. They would be astonished to see the amount of information that has accumulated about how cells work, how brains work and would conclude, “OK, they are getting it. Just like cells are complex wonderful machines, so are brains. They work in cool ways even though there is this strong tug on them to think there is some little guy in their head calling the shots. There is not.”

The world is not flat. Before this truth was realized, people use to wonder what happened when you got to the end of the earth-- did you fall off? Once we knew the earth was round, the new perspective, made us see how the old questions were silly. New questions also seem silly many times until a new perspective is accepted. I think we will get over the idea of free will and and accept we are a special kind of machine, one with a moral agency which comes from living in social groups. This perspective will make us ask new kinds of questions.

Cook: Are there particular experiments which you think have shed important light on the question of free will?

Gazzaniga: All of neuroscience in one way or another is shining light on how the brain works. That is the reality of it and it is that knowledge, slowly accumulating that will drive us to think more deeply. One way to get going on this is to try and answer the simple question. Free from what? What does anybody want to be free from? I surely do not want to be free from the laws of nature.

Cook: Do you think this science is going to force philosophers to change how they think about free will? And how about the rest of us?

Gazzaniga: Human knowledge can’t help itself in the long run. Things slowly, gradually become more clear. As humans continue on their journey they will come to believe certain things about the nature of things and those abstractions will then be reflected in the rules that are set up to allow people to live together. Beliefs have consequences and we will see them reflected in all kinds of ways. Certainly how we come to think and understand human responsibility in the context of modern knowledge of biologic mechanisms will dictate how we choose our laws and our punishments. What could be more important?

Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe. He can be reached at garethideas AT gmail.com or Twitter @garethideas.