David Bohm (1917–1992) was an American theoretical physicist whose career was shaped by two forces: his extraordinary insight into quantum mechanics, and his political persecution — he was one of the scientists called before the House Un-American Activities Committee during the McCarthy era, and was forced to leave the United States in 1951. He eventually settled in London, where he spent the rest of his career at Birkbeck College.
Bohm had worked closely with Einstein, who considered him one of the few physicists who genuinely understood the philosophical implications of quantum mechanics. Einstein's famous objection to quantum mechanics — that it was incomplete, that "God does not play dice" — resonated with Bohm's own discomfort with the Copenhagen interpretation's refusal to describe what was actually happening in quantum systems between measurements.
In 1952, Bohm published a paper that shocked the physics community: a hidden variable interpretation of quantum mechanics — later called pilot wave theory or Bohmian mechanics — that described quantum particles as having definite positions at all times, guided by a "pilot wave" that carried information about the entire experimental setup. This showed that the Copenhagen interpretation's claim that quantum mechanics was complete was not necessarily true — there were alternative interpretations that were equally consistent with all experimental data. The implications were profound: the apparent randomness of quantum mechanics might conceal a deeper deterministic order.
Over the following decades, Bohm developed his pilot wave theory into the much larger framework of the implicate and explicate orders — a comprehensive vision of the nature of reality that addressed not only quantum mechanics but consciousness, meaning and the relationship between mind and matter.