Definition
Free will is the contested idea that a person, faced with a choice, could genuinely have chosen otherwise — that the decision was authored by the self rather than fully fixed by what came before.
It is one of the central questions of Behave. The book asks whether, given a complete account of a person's genes, brain, hormones, upbringing, and circumstances, there is any room left for an uncaused chooser inside.
Why it matters
How it works
Behave's argument is cumulative. Each topic traces a behavior backward — to the second before, the hormones that morning, the adolescence, the childhood, the womb, the genes, the culture, and the evolutionary past. At no point does the chain hand control to a self standing outside the causes.
Sapolsky takes the strong position: there is no free will in the libertarian sense, and behavior is the product of biology and environment all the way down. He argues this should change how we treat wrongdoing — replacing retribution with the more practical questions of protection and reduction.