Closing the 'free will' loophole

In a paper published this week in the journal Physical Review Letters, MIT researchers propose an experiment that may close the last major loophole of Bell's inequality -- a 50-year-old theorem that, if violated by experiments, would mean that our universe is based not on the textbook laws of classical physics, but on the less-tangible probabilities of quantum mechanics. Such a quantum view would allow for seemingly counterintuitive phenomena such as entanglement, in which the measurement of one...