[B]y closing the two main loopholes at the same time, three teams have independently confirmed that we must definitely renounce local realism... Alth… - Alain Aspect

The most remarkable feature of Bell's work was undoubtedly the possibility it offered to determine experimentally whether or not Einstein's ideas could be kept. The experimental tests of Bell inequalities gave an unambiguous answer: entanglement cannot be understood as usual correlations, whose interpretation relies on the existence of common properties, originating in a common preparation, and remaining attached to each individual object after separation, as components of their physical reality.

We pretend that if I get result +1 here, immediately the photon there is in the state |x>, but if I find -1, immediately the other photon assume[s] another state of polarization... [T]his image is not acceptable for Einstein because it seems as [though] something is going . ...It is by this ...reasoning that Einstein said... "If you want to make sense of this correlation at a distance, you have to accept that before they arrive at the measuring apparatus, the particles have already a property determining the outcome." ...Bohr disagreed immediately. ...I don't know anybody who finds Bohr's reply understandable. It's not a joke, what I'm going to say, although it sounds [like] a joke. Bohr is so cautious in his wording that he makes it almost impossible to understand... Bohr insisted on... complimentarity, and at one point he declared... that "Clarity and truth are complimentary," and he made all efforts to be as true as possible.

I think it is not an exaggeration to say that the realization of the importance of entanglement and the clarification of the quantum description of single objects have been at the root of a second quantum revolution, and that John Bell was its prophet. And it may well be that this once purely intellectual pursuit will also lead to a new technological revolution.