Without the belief that it is possible to grasp the reality with our
theoretical constructions, without the belief in the inner harmony of our
world, there could be no science. This belief is and always will remain the
fundamental motive for all scientific creation. (Albert Einstein and
Leopold Infeld in The Evolution of Physics)
Quantum theory is the most successful physical theory yet devised. Not one of the multitude of its calculated predictions has ever been found wanting, even in the last measured decimal place. All the same, it is a bizarre theory, so much so that Richard Feynman, one of the deepest scientist-thinkers of our century and one not known for his intellectual (or any other) modesty, once said that ``I think I can safely say that nobody understands quantum mechanics.'' According to its traditional Copenhagen interpretation, quantum mechanics marks a sharp departure from the belief and scientific ideal of Einstein, expressed by the above quotation, replacing it with the view that the aim of physics is not to grasp any objective reality but merely to describe our observations, and that, indeed, there is no quantum reality.
Many physicists have been unhappy with such an austere view of quantum physics, and they have provided us with a bewildering variety of peculiar quantum realities and quantum paradoxes, including multiple universes (the many-worlds interpretation of quantum mechanics), observer-created reality, spooky-action-at-a-distance, reality founded upon a repudiation of classical logic, reality grounded in minds alone (the many-minds interpretation of
quantum mechanics), and a reality involving transitions from irreducible potentiality to definite actuality. At the same time, it has often been claimed that quantum phenomena are demonstrably incompatible with a more normal and less romantic account of physical reality, one in which objects of a precise and unambiguous character behave in a coherent and sensible way. In other words, it has been claimed that the sort of reality that Einstein might have found acceptable is impossible.
About Sheldon Goldstein
Sheldon Goldstein is a Distinguished Professor of Mathematics at Rutgers. Visit his homepage for more information: https://sites.math.rutgers.edu/~oldstein/