On Newton (1927)

that a theory which accounts for the results of all experiments - as quantum mechanics could - is complete. But Einstein contended that a theory which gives no account of the real world, but only of our imperfect (probabilistic) knowledge ofthat world, is incomplete. Partly for this reason, the world's most renowned scientist, during the last 20 years of his life, felt almost completely isolated in his scientific work and goals. The situation began to change, however, shortly before Einstein's death in 1955. Today, the subjects of Einstein's own scientific efforts - the general theory of relativity and the unification of the various physical forces (gravitation, electromagnetism, and so on) in a single field theory - have gradually become two of the most important foci of attention in physics. More to the point of Einstein's 1927 essay, physicists since the early 1950s have been less and less joyful about the indeterminism of our most fundamental theory, more and more ready to declare this feature of quantum mechanics unsatisfactory.