I just saw an ad (in Blackwell’s Books) for a book titled Einstein and the Quantum, with a text that began

Einstein himself famously rejected quantum mechanics with his God does not play dice theory…

Putting aside the fact that “God does not play dice with the universe” is a quip, not a theory, I’m fascinated by this extreme statement of a calumny on Einstein that I knew as standard when I first learned about quantum mechanics from popular science in the 1970s, that the old man, despite his revolutionary past (and he was only in his late 40s) simply lacked the intellectual flexibility to keep up, rejected the new science, and was proved wrong by the march of progress.

In fact, that famous remark (from a 1926 letter to Max Born) acknowledged up front that the emerging probabilistic view of quantum mechanics was proving very useful. He simply rejected the willingness to deny a micro-level interpretation. (And the so-called Copenhagen “Interpretation” of quantum mechanics is really an anti-interpretation, a programmatic refusal to interpret. For more comments on the pedagogical function, see here.) The fact that this approach went from strength to strength as a calculating tool does not mean that its interpretive framework, the one that said that probabilities are the fundamental objects and there is no use going deeper, has been proved, any more than the success of Maxwell’s equations proved the existence of molecular vortices in the luminiferous aether. In particular, proponents of the Copenhagen Interpretation have tended to ignore the fact that they are helping themselves to a supposedly primitive concept, probability, that is actually complex, strange, and sorely in need of physical foundations.

Certainly one powerful strain of modern work on the foundations of physics — in particular, the Everett interpretation of quantum mechanics (cf. David Wallace’s The Emergent Multiverse) also rejects the notion that there is some randomness at the core of quantum mechanics, and takes as a point of departure the entanglement theory first proposed in the Einstein-Podolsky-Rosen thought experiment.

* Einstein wrote, “Die Theorie liefert viel, aber dem Geheimnis des Alten bringt sie uns kaum näher. Jedenfalls bin ich überzeugt, daß der nicht würfelt.“ Literally: “The theory gives us much, but it hardly brings us nearer to the Ancient One’s secret. In any case, I am convinced that he does not throw dice.”