The concept of reform is preceded by a brief recount of the “lepers’ plot,” in which people with leprosy were unjustly accused of and confessed to poisoning water supplies, but they claimed they were encouraged to do it by Jewish people. When confronted, Jewish people blamed Muslim people, but since the latter were out of reach, the Jewish people and people with leprosy were killed.

Sapolsky discusses the reforms needed in the criminal justice system, citing its biases and high rates of recidivism. The justice system has undergone reform across the centuries. Early practices, such as those involved in trying witches, are now viewed as barbaric. Sapolsky also describes the graphic execution of Robert-Francois Damiens, who attempted to kill King Louis XV and was drawn and quartered in consequence.

Trials, Sapolsky posits, should be replaced with nonjudgmental investigations focused on finding the truth rather than on assigning blame. A few alternatives to the criminal justice system have been attempted; Sapolsky briefly discusses reconciliatory and restorative justice systems, which he deems irrelevant, and then focuses on quarantine systems as the most effective alternative and the one most likely to be accepted. The widely used quarantine system runs on four principles—that a person can be dangerous, that it is not the person’s fault, that it is okay to constrain their freedom for the sake of others’ safety, and that they should be minimally constrained.