Robert M. Sapolsky, a Stanford neuroscientist and primatologist best known for his earlier book Behave, uses Determined to make his most direct case yet: free will, in any meaningful sense, doesn't exist, and every decision a person makes is the downstream product of genetics, hormones, childhood environment, and a chain of prior causes stretching back further than anyone can consciously access. He builds the argument methodically, moving through neuroscience, genetics, and developmental biology to show how much of what feels like deliberate choice is shaped by factors entirely outside a person's control, and then follows that argument to its uncomfortable conclusions about praise, blame, and how a justice system built on personal responsibility might need to change. It's not a casual argument, Sapolsky spends the book anticipating and answering the objections that philosophers and general readers alike tend to raise, while staying grounded throughout in the same behavioral biology background that made Behave a widely respected work.
Written by a Stanford Neuroscientist and Primatologist
Sapolsky's dual background studying both human neuroscience and primate behavior in the field gives the book's arguments a breadth few other writers on free will can bring to the topic.
Extends Arguments Developed in His Earlier Book Behave
Determined builds directly on the behavioral biology framework Sapolsky laid out in Behave, applying that same research background specifically to the question of whether free will exists at all.
Argues for a Hard Determinist Position Without Compromise
Unlike compatibilist writers who try to preserve some version of free will alongside determinism, Sapolsky takes an uncompromising hard determinist stance that leaves no meaningful room for free choice.
Traces Behavior Back Through Genetics, Hormones, and Childhood
The book methodically walks through layers of causation, from genetics and hormones to childhood environment and culture, building a cumulative case that choice is shaped by forces outside conscious control.
Directly Addresses Implications for Blame and Punishment
Sapolsky follows his neuroscience argument into its ethical implications, questioning whether praise and blame in the traditional moral sense can survive once free will is taken off the table.
Anticipates and Responds to Philosophical Objections
Rather than ignoring pushback, the book spends significant space anticipating counterarguments from philosophers and general readers, engaging directly with the strongest objections to hard determinism.
Remains a Genuinely Contested Position Among Philosophers
The book's hard determinist conclusions are far from universally accepted, with many philosophers holding compatibilist views that Sapolsky's argument doesn't fully accommodate, keeping the debate open.
Why Determined Sparked Wide Debate Beyond Neuroscience Circles
Determined continues generating discussion well outside neuroscience because its conclusions touch directly on how society assigns responsibility, making it relevant to readers interested in law, ethics, and psychology alike.
Pros and Cons
Pros:
- Written by a leading neuroscientist with deep behavioral biology credentials
- Builds a methodical, well-evidenced case rather than relying on assertion alone
- Directly engages philosophical objections instead of avoiding them
- Extends and sharpens arguments from the author's respected earlier work
- Pushes readers to seriously reconsider assumptions about blame and justice
Cons:
- Its uncompromising stance leaves little room for readers who lean compatibilist
- Dense in places, with heavier science than casual readers may expect
- Its implications for justice and punishment remain more theoretical than practical
Frequently Asked Questions
Does the author believe in any form of free will at all?
No, he argues for a hard determinist position, that every choice is fully the product of prior biology and environment, with no meaningful gap left for free will to operate in.
Is this book connected to the author's earlier work?
Yes, it extends arguments the author developed in his earlier book Behave, applying the same neuroscience and behavioral biology background to the specific question of free will.
What does the book say about punishing people for their actions?
It argues that if free will doesn't exist, praise and blame in their traditional moral sense don't hold up, which has direct implications for how the author thinks about criminal justice.
Do philosophers agree with the book's conclusions?
No, the hard determinist stance is genuinely contested among philosophers, some of whom argue compatibilist positions the book doesn't fully accept.
Final Verdict
Determined is a demanding but rewarding read that takes Robert M. Sapolsky's decades of neuroscience and behavioral biology research to their most uncompromising conclusion: free will, as most people understand it, doesn't hold up. The book's real strength is refusing to stop at the neuroscience, following the argument into its genuinely uncomfortable implications for blame, punishment, and justice, and engaging honestly with the philosophical objections that follow. Readers looking for a tidy resolution won't find one, but anyone willing to sit with a rigorously argued, contested idea will find this among the more substantial books on the subject.
Rating: 4.6/10