The boundary between mind and matter could be tested using a new twist on a well-known experiment in quantum physics. Over the past two decades, a type of experiment known as a Bell test has confirmed the weirdness of quantum mechanics – specifically the 'spooky action at a distance' that so bothered Einstein. Now, a theorist proposes a Bell test experiment using something unprecedented: human consciousness. If such an experiment showed deviations from quantum mechanics, it could provide the first hints that our minds are potentially immaterial. Spooky action at a distance was Einstein’s phrase for a quantum effect called entanglement. If two particles are entangled, then measuring the state of one particle seems to instantly influence the state of the other, even if they are light years apart. But any signal passing between them would have to travel faster than the speed of light, breaking the cosmic speed limit. To Einstein, this implied that quantum theory was incomplete, and that there was a deeper theory that could explain the particles’ behaviour without resorting to weird instantaneous influence.
Nowadays, researchers proposed an experiment in which A and B are set 100 kilometres apart. At each end, about 100 humans are hooked up to EEG headsets that can read their brain activity. These signals are then used to switch the settings on the measuring device at each location. The idea is to perform an extremely large number of measurements at A and B and extract the small fraction in which the EEG signals caused changes to the settings at A and B after the particles departed their original position but before they arrived and were measured. If the amount of correlation between these measurements doesn’t tally with previous Bell tests, it implies a violation of quantum theory, hinting that the measurements at A and B are being controlled by processes outside the purview of standard physics. Such a finding would stir up debate about the existence of free will. It could be that even if physics dictated the material world, the human mind not being made of that same matter would mean that we could overcome physics with free will.