Determined: A Science of Life Without Free Will

Overview

Determined: A Science of Life Without Free Will (2023) is the culmination of Robert Sapolsky's decades of work as a neurobiologist and primatologist. In it, he argues that the entire history of the free will debate has been conducted on the wrong assumption: that there might be some domain of human behavior — a "crack" in the causal order — where free will could operate. Reviewing the neuroscience, the genetics, the endocrinology, the developmental biology, and the sociology of behavior, Sapolsky concludes that there is no such crack. Free will, he argues, is an illusion.

The book is enormous in scope and famously detailed. Sapolsky walks through every level of explanation for human behavior — from the firing of a single neuron, to the influence of hormones and genes, to the effects of childhood, culture, and history — showing at each level that behavior has causes. His conclusion is blunt: because every event in the causal chain is fully determined by what precedes it, there is no room for an agent who could have done otherwise.

The book's second half addresses the consequences. If free will is an illusion, Sapolsky argues, we must change how we think about moral responsibility, punishment, and justice. He does not conclude that anything goes; he argues, instead, that we should stop treating people as deserving of retribution and focus on preventing harm and repairing it. The book is a hard determinist manifesto written by a scientist who has thought deeply about what the position entails.

Core Thesis

The core thesis of Determined is that free will does not exist, because human behavior is fully determined by factors over which the individual has no ultimate control. Sapolsky argues that the folk notion of free will — the idea that a person could have done otherwise, given the very same biology, history, and circumstances — is scientifically indefensible. Every behavior, he argues, is the product of a chain of causes that extends backward in time and outward into the environment.

The thesis is defended by a comprehensive review of the causes of behavior. Genes influence temperament; hormones influence mood and impulse control; childhood experience shapes the developing brain; culture and socioeconomic conditions shape the opportunities and stresses of life; and every one of these factors has its own causes, in an unbroken chain. At no point in the chain, Sapolsky argues, does an uncaused agent insert itself.

The thesis has a normative corollary: because no one ultimately deserves praise or blame for what they do, the retributive practices of punishment — and the "desert" they presuppose — must be abandoned. Sapolsky is careful to distinguish his position from nihilism: he thinks we still need to protect people from harm, to hold people to reasonable standards where they are capable of meeting them, and to build a society that reduces the causes of harmful behavior. But we must stop pretending that the criminal "deserves" to suffer.

Key Ideas

There Is No "Crack" in the Causal Order

Sapolsky's central argumentative strategy is to search for a place where free will could hide — a gap in the causal explanation of behavior — and to show that no such gap exists. He examines the usual candidates: the quantum uncertainty at the subatomic level, the chaotic dynamics of complex systems, the "emergent" properties of brains. In each case, he argues, the candidate fails to deliver the kind of freedom that would matter.

Quantum indeterminacy, he argues, is random noise, not freedom: a choice that is the product of randomness is no more free than one that is fully determined. Chaos theory shows that small differences produce large effects, but the effects are still caused. Emergence is real — complex systems have properties their parts lack — but emergent properties are still determined by their bases. The conclusion is that determinism, in the sense that matters, holds for every behavior.

Behavior Has Causes at Every Level

The book's distinctive contribution is its comprehensiveness. Where philosophers argue from the logic of determinism, Sapolsky argues from the science: he shows, level by level, that behavior is caused. Neurons fire because of inputs; circuits activate because of neuromodulators; individuals respond because of their genes and hormones; the whole system is shaped by development and environment. The book reads like a grand tour of the behavioral sciences, and its cumulative effect is the intended one: by the end, the claim that behavior has causes seems too obvious to deny.

Sapolsky emphasizes that this is not a claim about "free will in the brain" — as if some part of the brain were free while others are determined. The entire brain is a physical system, and physical systems have causes. The idea that a special process inside the head could be exempt from causation is, he argues, a relic of dualist thinking.

The Libet Experiments

Sapolsky gives the Libet experiments — the 1980s studies showing that a "readiness potential" in the brain precedes the conscious intention to act by hundreds of milliseconds — a central place in the book, while being scrupulous about what they do and do not show. He acknowledges the objections: that Libet's findings concern timing, not causation; that the readiness potential may not be the cause of the movement; that some later studies have failed to replicate the original pattern.

His verdict is that the Libet experiments, despite their flaws, point in the right direction: they provide a glimpse of the machinery of action that runs before conscious awareness, and they suggest that the feeling of initiating action is a construction of a system that has already begun to act. The intuition of "I decided, and then my brain acted" is, he argues, back to front.

Compatibilism Is a Retreat

The book is as much a polemic against compatibilism as against libertarianism. Sapolsky engages directly with Dennett's claim that the "free will worth wanting" survives determinism, and he rejects it: compatibilism, he argues, changes the subject. A compatibilist "free will" is not the freedom the folk believe in — the freedom that underwrites the sense that we are the genuine authors of our actions and the ultimate sources of our choices.

Sapolsky insists on what he calls the "chaos of the everyday" — the sense, familiar to everyone, that one could have done otherwise. That sense, he argues, is an illusion, and no amount of philosophical refinement should obscure it. His position is that we should face the truth plainly: we are what our biology and history have made us, and we did not make ourselves.

Rethinking Responsibility and Punishment

The final part of the book argues for a reform of moral and legal practices. Since no one deserves retribution, Sapolsky argues, we should abolish the retributive elements of punishment and replace them with consequentialist measures: incapacitation where needed, rehabilitation where possible, and a focus on preventing harm rather than exacting payback.

He is careful to distinguish several questions that are often conflated. Whether someone is a dangerous person is a factual question about risk. Whether someone could have behaved differently is a metaphysical question about determinism. Whether someone should be locked up is a policy question about public safety. Sapolsky's claim is that the metaphysical question — answered negatively — should reshape the policy answers, without collapsing into either cruelty or sentimentality.

Historical Context

Determined belongs to a long tradition of hard determinism in philosophy — the view that determinism is true and that free will, understood as the power to do otherwise, does not exist. The tradition runs from Spinoza, through the French materialists, to the scientific naturalists of the nineteenth century and the "no-free-will" skeptics of the late twentieth century, such as Galen Strawson and Derk Pereboom.

The book also belongs to the more recent tradition of neurophilosophy and the popular science of the mind. It stands in a line with Libet's original experiments, with the "neuroscience of free will" debates of the 2000s, and with the growing literature questioning the retributive basis of criminal justice. Sapolsky's distinctive contribution is the breadth of his scientific review: no other work in the popular literature has marshaled so much evidence from so many levels of biological explanation.

The book is explicitly a response to compatibilist and libertarian philosophers, and it engages with the arguments of Dennett, van Inwagen, and others. Sapolsky's verdict on the entire philosophical debate is that it has been conducted in ignorance of the science — a provocative claim that has itself become part of the debate.

Legacy & Influence

Determined has become the standard popular statement of the hard determinist position, and it has reignited public debate about free will and moral responsibility. Its publication was followed by a wave of responses from philosophers, neuroscientists, and ethicists, and it has been widely discussed in the context of criminal justice reform.

The book's influence is partly argumentative and partly evidential. Philosophers have responded that Sapolsky's argument conflates determinism with the absence of freedom, and that compatibilism survives his critique — charges he addresses directly in the book. The broader public conversation, however, has been shaped by the book's insistence that the question is not academic: how we think about free will affects how we punish, how we educate, and how we treat one another.

For readers exploring the metaphysics and ontology of freedom, Determined pairs with the philosophical statements of the positions it attacks: Elbow Room for compatibilism, An Essay on Free Will for incompatibilism, and The Oxford Handbook of Free Will for the full range of the debate. The empirical questions are introduced in what is the Libet experiment, and the moral questions in what is moral responsibility.

Sources

• Robert M. Sapolsky, Determined: A Science of Life Without Free Will (New York: Penguin Press, 2023).
• Stanford Encyclopedia of Philosophy, Free Will.
• Stanford Encyclopedia of Philosophy, Moral Responsibility.
• Benjamin Libet, Curtis A. Gleason, Elwood W. Wright, and Dennis K. Pearl, "Time of Conscious Intention to Act in Relation to Onset of Cerebral Activity (Readiness-Potential)," Brain 106, no. 3 (1983): 623-642.
• Stanford Encyclopedia of Philosophy, Compatibilism.

Related Topics

• What is free will
• What is the Libet experiment
• What is moral responsibility
• Determinism
• Agency
• Elbow Room
• The philosophy of neuroscience