On the modern understanding of the “EPR paradox”

The concepts of quantum nonlocality, quantum superposition, the absence of a priori values of observables before measurement, and the ultimate precision of quantum measurements are analyzed in connection with the “EPR paradox” and subsequent studies stimulated by it. The relationship between the Heisenberg uncertainty principle and the precision of measurements is discussed in connection with the disappearance of interference in “which way?” schemes and the “EPR paradox”. It is shown that the absence of a priori values of observables before measurement and the existence of quantum nonlocality – in the sense of instantaneous reduction of quantum states of distant objects and the connection between their measured values – are beyond doubt.