In light of technology that may reveal the content of a person’s innermost thoughts, I address the question of whether there is a right to ‘brain privacy’—a right not to have one’s inner thoughts revealed to others–even if exposing these thoughts might be beneficial to society. I draw on a conception of privacy as the ability to control who has access to information about oneself and to an account that connects one’s interest in privacy to one’s interests in autonomy and (...) associated reputational interests, and preserving one’s dignity. Focusing on the controversial case of Gilberto Valle, known as the ‘cannibal cop’, who faced legal punishment and moral reproach for deeply disturbing thoughts of doing violence to women, thoughts he claimed were mere fantasies, I argue that Valle has a right to brain privacy if he has a legitimate privacy interest that is not outweighed by competing societal interests in avoiding harm. Our weighing of competing privacy and societal interests will depend on the magnitude of the privacy interests in autonomy and dignity, and on how reliable the technology used to expose inner thoughts is in predicting future harmful behavior and identifying true threats. (shrink)