One night in 1952, Richard Feynman and David Bohm went bar-hopping in Belo Horizonte. Louisa Gilder reconstructs the night in her brilliant book on the history of quantum mechanics, The Age of Entanglement . Feynman was on a sabbatical in Rio and, ever exuberant, raved about local beers, drumming lessons, and Brazilian girls. Bohm, teaching at the University of S?o Paulo, never took to the place. He had just been hounded out of Princeton University and out of the U.S. by the McCarthy witch hunt. He felt exiled not just from his country but from the mainstream of physics. Bohm perked up only when Feynman expressed some fleeting interest in his new way of thinking about quantum mechanics.

Bohm had developed the first comprehensive alternative to the orthodox Copenhagen Interpretation of quantum mechanics. Building on earlier work by Einstein and Louis de Broglie, Bohm showed that quantum randomness need not be intrinsic to nature. It might simply reflect our bull-in-a-china-shop way of probing the quantum realm. In Bohm’s original formulation, particles always have well-defined positions and are shepherded by a “quantum potential” similar in general spirit to electric and gravitational forces. Because this potential operated instantaneously, linking together everything in the universe no matter how far apart it may be, Bohm later came to think that quantum physics was just the surface view of a radically holistic reality.