On a Mission to Defend Free Will

Neuroscientist Peter Tse's first book on free will helped free an innocent man who had served more than a decade of a life sentence for murder. 

It's an unlikely claim for any book, especially a scholarly monograph, but The Neural Basis of Free Will: Criterial Causation, published in 2013, posits a powerful theme: humans can shape their futures, as evidenced in the brain at a neural level. 

"Due to your writings, Sargent Raymond Jennings is a free man enjoying life with his five children, instead of being locked in a cage for a crime he did not commit," a young man named Clinton Ehrlich wrote to Tse in 2018. 

As a law student, Ehrlich had seen a television program about Jennings, who had been convicted of killing teenager Michelle O'Keefe in 2000. He suspected the local police and FBI had mishandled the case and convinced his father, an attorney, to join him in pursuing a new investigation, which confirmed Jennings' innocence in 2017. 

"Realizing that my brain was endowed with true free will was as intense a revelation for me as a stereotypical religious conversion," Ehrlich wrote. "I can tell you unequivocally that I never would have been inspired to take on that challenge and follow my moral intuition had I not read The Neural Basis of Free Will." 

Tse's 2013 book was published on the heels of works by a number of prominent scientists and writers who claimed that free will is an illusion. Neuroscientists, in particular, traditionally envision the brain as a predictable physical system, with human behavior arising from neurophysiology. 

"This widely held belief among scientists that we are all nothing more than biochemical puppets is a hopeless, demoralizing message and utterly wrong," says Tse '84, professor and chair of the Department of Psychological and Brain Sciences. "I'm kind of at war with that misinformation. Part of my mission is to showcase the role of human agency and human consciousness."

Building on his first book and more than a decade of interdisciplinary research and analytical philosophy on human consciousness, Tse recently authored two books on free will from Oxford University Press, A Neurophilosophy of Libertarian Free Will and Free Imagination: The Deep Roots of Creativity, Freedom, and Meaning in the Human Brain and Mind. Planned as a trilogy, a third book, Re-Enlightenment, which examines societal influences on human agency, is slated for 2025. 

The first volume revisits Tse's reconceptualization of the neural code with recent neuroscience research and details how neurons rewire each other—enabling a uniquely human "second-order free will" that "concerns envisioning a new self, then working toward the realization of that vision over a long period of time," Tse says. 

Simply put, neurons in the brain rapidly recode the criteria that must be met for neuronal firing to be triggered in the future, Tse says—an argument that upends the theory that all mental events, including volitional thoughts, are predetermined. 

Mental causation doesn't act as a force, Tse says, "but more like a filter that sculpts out the possibilities that we want to happen."  

Free Imagination delves into our dynamic inner lives as the "real engine of free will"—intricate internal operations that allow us to imagine different futures and even different selves. 

"For example, you could decide to learn Arabic," Tse says. "You could go on Duolingo or go live in Morocco and do all kinds of stuff that will then lead you to having a new kind of nervous system, namely, one that in the future can process Arabic. I argue that humans are different from any other animal because we can actually will to have a new kind of self." 

For instance, Tse says, we can enhance our own attentiveness and empathy. 

"We can transform our capacity to pay attention by meditating," he says. "We can become kinder by trying to pay attention to other people in a real way, to truly empathize with other people rather than treating them as tokens of some category." 

Tse calls the human imagination our greatest tool as well as our greatest weapon, including against ourselves. The Holocaust, for example, was an act of imagination long before it was enacted in the world. 

"If we want a better world, we have to first imagine that world, and then we have to fight to make it happen," he says. 

With proper guidance from friends, family, and the "scaffolding" of society, Tse says, we can foster an imagination that benefits not only ourselves, but the world at large. 

Searching for Truth

For his part, Tse credits the Dartmouth community for shaping his intellectual journey, as both a student and professor. 

As an undergraduate physics and mathematics major, he discovered the interconnectedness of the liberal arts early on. 

"When you go deeply enough into almost any discipline, it connects with almost everything," he says. "And so if you bore down deeply into neuroscience, you're going to end up dealing with philosophical problems like the mind-body problem, which asks, how can the mind be causal?"

In 2011, Tse and several of his Dartmouth neuroscience and philosophy colleagues took part in a multi-institutional research project titled "Big Questions in Free Will" co-sponsored by the John Templeton Foundation. They revisited an influential set of studies from the 1980s led by neurophysiologist Benjamin Libet that used electroencephalography to study brain activity. 

Libet claimed that because EEG data shows a buildup of activity in the brain prior to a person having a conscious thought about moving, free will could not cause either the buildup of electrical signals or the subsequent movement.

The Dartmouth researchers identified flaws in both the studies and their interpretation. 

"This interdisciplinary work played a role in getting me into speaking with philosophers," Tse says. "I found these interactions super interesting and challenging, and I really tried hard to train myself in analytical philosophy."

He draws energy from being part of "a community of people who are all in search of deeper meanings and forms of truth" and says that his friendships with colleagues fostered by co-teaching classes and sharing students leads to levels of trust and communication that drive interdisciplinary discoveries. 

The collaborative research on free will inspired Tse to author his influential first book, and also to create a MOOC (massive open online course) for the general public that summarizes studies and insights on free will from both  philosophy and neuroscience. Encompassing 83 videos and now available on YouTube, the course encompasses philosophers from Aristotle to Wittgenstein alongside scientific studies on the neural underpinnings of consciousness. 

Tse has received thank-you messages from hundreds of people around the world who took the course.

"This includes many people who said they had been depressed because they believed they had no agency to change their lives," Tse says. 

"Ideas matter, and the most fundamental to human action is the conviction that you can make a difference, that you have agency, that you have some say in the matter of what becomes of you and what becomes of your world."