Schrödinger’s Cross: The Quantum Mechanics of the Establishment Clause

Joseph Blocher, Duke Law School

Available in the Faculty Scholarship collection.


Perhaps the most famous character in modern physics is Schrödinger’s Cat, an unfortunate feline trapped in a box alongside a flask containing deadly poison that may or may not have been released. Thanks to the wonders of quantum mechanics, the cat is both alive and dead — “mixed or smeared out in equal parts” — until the box is opened, at which point the act of observation causes its state to collapse into either life or death.

Far away in the Mojave Desert, the “life” of a six-foot-tall cross is disputed: it is either a religious symbol or it is not. Like the cat, it has spent much of its life (or non-life) in a box that makes direct observation impossible. Is the cross, like the cat, both alive and dead? And does opening the box — either metaphorically or otherwise — cause it to become one or the other? This short Article argues that recent forays into “constitutional physics” may have over-emphasized the role of box-opening judges, and thereby elided the cat’s predicament and the relationship between legal and social reality.