For Bohr, physics was not about finding out what nature is, but about what can be said about it. Quantum mechanics was a complete theory of the behavior of matter and light, and we just have to come to terms with the limitations it places on what can be known, for example as illustrated by the Heisenberg uncertainty principle. Einstein was having none of it. He believed that there is an objective world out there and that it is the job of scientists to describe it. The appearance of probabilities in the theory was, for him, evidence of its incompleteness. …

In the late 1970s, I had the pleasure of talking with John Bell about the Bohr-­Einstein debates during a train journey from Oxford to London. Every seat was taken, so we had to stand. Pressed against me by sullen commuters, Bell summarized his apparently reluctant conclusion as we pulled into Paddington station: “Bohr was inconsistent, unclear, willfully obscure and right. Einstein was consistent, clear, down-to-earth and wrong.”