The mischievous oracle

From The Guardian:

Quantum: Einstein, Bohr, and the Great Debate About the Nature of Reality by Manjit Kumar

Quantum1 Manjit Kumar’s book is an exhaustive and brilliant account of decades of emotionally charged discovery and argument, friendship and rivalry spanning two world wars. In what also has to operate as a kind of group biography of Planck, Einstein, Bohr, Heisenberg, Pauli, Dirac et al, the quasi-novelistic character sketches occasionally have a comic quality (“The son of a tax collector, Ludwig Boltzmann was short and stout with an impressive late 19th-century beard”); but the real meat of the book is the explanations of science and philosophical interpretation, which are pitched with an ideal clarity for the general reader. Perhaps most interestingly, although the author is admirably even-handed, it is difficult not to think of Quantum, by the end, as a resounding rehabilitation of Albert Einstein.

You might have thought that Einstein, the most famous scientist who ever lived, was not much in need of rehabilitation. But for a long time, the standard story of his reaction to quantum theory painted him as a grouchy old man, whose great work was long in the past, and who could no longer accept novel ideas. The truth, as Kumar shows, is very different.

For a start, Einstein was himself a pioneer of quantum theory, having suggested in 1913 that light was quantised — in other words, that it was not smoothly continuous, but could only exist in multiples of very small packets, or quanta. At the time, Kumar relates, this was “just too radical for physicists to accept”. Two decades later, the great Danish physicist Niels Bohr and his colleagues, who had taken this idea and run with it, had become too radical for Einstein to accept.

More here.