(Below is a summary from ISBN: 978-0-19-975381-9)




  • (1927) At the Solvay conference, Einstein, by then the world’s most respected scientist, turned thumbs down on the newly minted Copenhagen interpretation. He insisted that even little things have independent reality, whether or not anyone is looking. If quantum theory said otherwise, it had to be wrong. Niels Bohr, the Copenhagen interpretation’s principal architect, rose to its defense. For the rest of their lives Bohr and Einstein debated as friendly adversaries.... With simple algebra, Bohr was able to show that this uncertainty for the slit diaphragm would be large enough to foil Einstein’s demonstration.
  • (1930) Three years later at another conference, Einstein proposed an ingenious thought experiment claiming to violate an alternate version of the uncertainty principle.... This one stumped Bohr through a sleepless night. But in the morning he embarrassed Einstein by showing that he had ignored his own theory of general relativity.
  • (1935) Four years later (in 1935), a paper by Einstein and two young colleagues... [disrupted Bohr's work in Copehagen.] The paper, now famous as “EPR” for “Einstein, Podolsky, and Rosen,” did not claim that quantum theory was wrong, just that it was incomplete. ... Bohr recognized Einstein’s “bolt from the blue” [as he called the EPR paper] as a serious challenge. He worked furiously for weeks to develop a response. A few months later he published a paper with exactly the same title as EPR. While EPR’s answer to the paper’s title question was “no,” Bohr’s was a firm “yes.”

    • As the EPR authors put it, "since at the time of measurement the two systems [particles A and B] no longer interact, no real change can take place in the second system in consequence of anything that may be done to the first system." 
    • Yet Bohr's response suggested something else entirely: the decision to conduct a measurement on particle A (either position or momentum) would instantaneously change the properties ascribed to the far-away particle B. Measure particle A's position, for example, and—bam!—particle B would be in a state of well-defined position. Or measure particle A's momentum, and—zap!—particle B would be in a state of well-defined momentum.


  • (1948) Late in life, Bohr's line still rankled Einstein. "My instinct for physics bristles at this," Einstein wrote to a friend in March 1948. "Spooky actions at a distance," he huffed.
  • (1950s) Einstein soon asked about our [the author and his friend's] quantum mechanics course. He approved of our professor’s choice of David Bohm’s book as the text, and he asked how we liked Bohm’s treatment of the strangeness quantum theory implied. We couldn’t answer....
  • To their dying days, Bohr and Einstein disagreed about quantum theory. For Bohr, the theory with its Copenhagen interpretation was the proper basis for physics. Einstein rejected Copenhagen’s concept of a physical reality created by “observation.”