abstract. It’s a venerable maxim of criminal jurisprudence that the state must never punish people for their mere thoughts—for their beliefs, desires, fantasies, and unexecuted intentions. This maxim is all but unquestioned, yet its true justification is something of a mystery. In this Essay, I argue that each of the prevailing justifications is deficient, and I conclude by proposing a novel one. The proposed justification captures the widely shared intuition that punishing a person for her mere thoughts isn’t simply disfavored by the balance of reasons but is morally wrongful in itself, an intrinsic (i.e., consequence-independent) injustice to the person punished. The proposed justification also shows how thought’s immunity from punishment relates to a principle of freedom of mind, a linkage often assumed but never explained. In explaining it here, I argue that thought’s penal immunity springs from the interaction of two principles of broad significance: one familiar but poorly understood, the other seemingly unnoticed. The familiar principle is that persons possess a right of mental integrity, a right to be free from the direct and forcible manipulation of their minds. The unnoticed principle, which I label the Enforceability Constraint, is that the state’s authority to punish transgressions of a given type extends no further than its authority to thwart or disrupt such transgressions using direct compulsive force. Heretofore unexamined, the Enforceability Constraint is in fact a signal feature of our system of criminal administration, governing the scope and limits of the criminal law.

author. Assistant Professor of Law and of Philosophy, University of Michigan. I’m grateful to audiences at the American Philosophical Association Central Division Conference, the Analytical Legal Philosophy Conference, the Fordham Law School Criminal Law Theory Discussion Group, the London School of Economics Criminal Law and Criminal Justice Theory Forum, the University of Michigan Criminal Law Theory and Legal Theory Workshops, the University of Oxford Criminal Law Discussion Group, the Queen’s University Faculty of Law, the University of Surrey School of Law Faculty Research Seminar, the University of Toronto Faculty of Law Criminal Law Theory Lab, the Yale Law School Legal Theory Workshop, and a symposium conference at Osgoode Hall Law School on the scope and limits of the criminal law. Special thanks to Larry Alexander, Paul Audi, Marcia Baron, Mitch Berman, David Brink, Sarah Buss, Jules Coleman, Nico Cornell, Susan Dimock, Antony Duff, James Edwards, Chris Essert, Rich Friedman, Stephen Galoob, Tom Green, Monica Hakimi, Daniel Halberstam, Scott Hershovitz, Don Herzog, Doug Husak, Brian Hutler, Vic Khanna, Josh Kleinfeld, Adrienne Lapidos, Kyle Logue, Daniel Markovits, Bill Miller, Michael Moore, Julian Mortenson, Federico Picinali, J.J. Prescott, Eve Primus, Richard Primus, Don Regan, Jed Rubenfeld, Alex Sarch, Scott Shapiro, Seana Shiffrin, Sonja Starr, Hamish Stewart, Malcolm Thorburn, Peter Westen, Gideon Yaffe, and Taisu Zhang. For research assistance, I’m grateful to Daniel Fryer, Andrew Jordan, Ross Macpherson, and Virginia Neisler, the Faculty Services Librarian at Michigan Law School. I also would like to thank the editors of the Yale Law Journal, especially Leslie Arffa. Research for this project was funded in part by the Cook Endowment.