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The first blow to deterministic theories of Nature came with the formulation by Werner Heisenberg (December 5, 1901- February 1, 1976) of the Uncertainty Principle in Quantum Mechanics, stating that simultaneous measurement of all physical variables of a system is impossible; thus we cannot know both the position AND the velocity of a particle to arbitrary precision. Any measurement of the position introduces errors in the estimate of velocity and vice versa. And if we cannot know the position and velocity to arbitrary precision, we cannot predict its future motion ... Thus Quantum Mechanics is fundamentally indeterministic, said the soothsayers of the 'Copenhagen Interpretation'