The Neuroscience of Freedom and Creativity
October 2000, University of Paris, La Salpêtrière Hospital, Charcot Amphitheater. I was invited to give a short acceptance speech on a subject of my choosing after being awarded the Jean-Louis Signoret Prize. Determined to deliver it in French, I gave it an ambitious title: “Liberté et l’Exécutif du Cerveau.” In less than half an hour I tried to explain that the prefrontal cortex is the cerebral enabler of the human agenda. Further, that the achievement of biological and social goals is the outcome of the competition between demands of internal and external milieus continuously barraging that cortex. Further, that those demands include unconscious ethical imperatives in addition to instinctual urges. Of course, I dutifully cited Claude Bernard and Benjamin Constant. Human liberty, I concluded, is a phenomenon of the brain’s ability to choose, rationally or not, between alternatives of action.
Only after my talk did I realize I had overreached. I had spoken about a sacred French theme in less than perfect French to an intellectual French audience in an august French forum. Now, a dozen years past, this book is an attempt to say all those things better, in English.
What motivates this brain scientist to write about such a lofty theme as human liberty? And what qualifications does he have to do it? He surely must know that the terrain is fraught with pitfalls. Emphatically yes, he knows the dangers. No one has to convince him that those dangers are very real, especially the disdain, or, worse, the implacable wrath, with which modern neuroscience treats the unsuspecting defender of free will.
Indeed, on neuroscientific grounds, the radical defense of free will is a lost cause, and it is not my intention to attempt it. What is defensible – my position here – is that the freedom or liberty to choose between alternatives is a function of the nervous system, especially the cerebral cortex, in its interaction with the environment. Further, that the freedom or liberty to choose between alternatives – including inaction – is relative, constrained by limits in both the organism and its environment. And further, that the subjective experience of freedom is a function of the intensity of the cortical activity that precedes and attends free choice.
A defense of freedom from the determinism of the brain’s microcosm of genes and molecules is practically impossible if we ignore that such a microcosm obeys the laws of the nervous system and its environment, and is no less subject to them than the ink is to the written word. Nonetheless, most everybody has a reason to deny liberty a place in that system. No structure within it seems to harbor the immense breadth of human purpose and the biological roots of human institutions. However, even if choice had a specific place in the brain, there would still remain the question of how the brain creates the new from the old. Karl Popper will eloquently win the argument against determinism in human action, but then concede that his victory is insufficient to understand the essence of freedom, responsibility, or creativity. He will wistfully ask himself, now how can we explain Mozart?
Without much success, some philosophers and sociobiologists attempt to anchor liberty beyond the nervous system. Evolutionary psychologists anchor the “illusion of freedom” in the phylogenetic history of mankind, but are seemingly unaware that something truly new has happened in that history to liberate man from his past, to open him to his future, and to make him capable of freely inventing that future. That something is the evolutionary explosion of the cortex of the frontal lobes, especially its prefrontal region.
Aside from the urge to redeem myself after an imprudent speech in French on liberty, what compels me to undertake this intellectual adventure is having devoted nearly half a century to research into that part of the brain. This does not mean that I see any brain structure, not even the cortex of the frontal lobes, as somehow escaping natural causality or as being endowed with the power to choose and decide for us. Quite the contrary, I view the dynamics of the frontal lobes as ultimately determined by the genome and the environment. Furthermore, the attribution of ultimate executive power to the prefrontal cortex is, as I will explain, a major obstacle to the study of its role in liberty. Yet, because of its prospective functions, that cortex extends the
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