So what does it all tell us? (Image: Paul Cooklin/Brand X Pictures/Getty)

It is tempting, faced with the full-frontal assault of quantum weirdness, to trot out the notorious quote from Nobel prize-winning physicist Richard Feynman: “Nobody understands quantum mechanics.”

It does have a ring of truth to it, though. The explanations attempted here use the most widely accepted framework for thinking about quantum weirdness, called the Copenhagen interpretation after the city in which Niels Bohr and Werner Heisenberg thrashed out its ground rules in the early 20th century.

With its uncertainty principles and measurement paradoxes, the Copenhagen interpretation amounts to an admission that, as classical beasts, we are ill-equipped to see underlying quantum reality. Any attempt we make to engage with it reduces it to a shallow classical projection of its full quantum richness.

Lev Vaidman of Tel Aviv University, Israel, like many other physicists, touts an alternative explanation. “I don’t feel that I don’t understand quantum mechanics,” he says. But there is a high price to be paid for that understanding – admitting the existence of parallel universes.

In this picture, wave functions do not “collapse” to classical certainty every time you measure them; reality merely splits into as many parallel worlds as there are measurement possibilities. One of these carries you and the reality you live in away with it. “If you don’t admit many-worlds, there is no way to have a coherent picture,” says Vaidman.

Or, in the words of Feynman again, whether it is the Copenhagen interpretation or many-worlds you accept, “the ‘paradox’ is only a conflict between reality and your feeling of what reality ought …