A classic quantum test could reveal the limits of the human mind – New Scientist

A quantum test could tell us what minds are made of

Dominic Lipinski/PA

By Anil Ananthaswamy

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 Einsteins 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. Some physicists have been trying to find this deeper theory ever since.

In 1964, physicist John Bell paved the way for testing whether the particles do in fact influence each other. He devised an experiment that involves creating a pair of entangled particles and sending one towards location A and the other to location B. At each point, there is a device that measures, say, the spin of the particle.

The setting on the device for example, whether to measure the particles spin in the +45 or -45 degree direction is chosen using random number generators, and in such a way that its impossible for A to know of Bs setting and vice-versa at the time of the measurement.

The measurements are done for numerous entangled pairs. If quantum physics is correct and there is indeed spooky action at a distance, then the results of these measurements would be correlated to a far greater extent than if Einstein was correct. All such experiments so far have supported quantum physics.

However, some physicists have argued that even the random number generators may not be truly random. They could be governed by some underlying physics that we dont yet understand, and this so-called super-determinism could explain the observed correlations.

Now, Lucien Hardy at the Perimeter Institute in Canada suggests that the measurements at A and B can be controlled by something that could potentially be separate from the material world: the human mind.

[French philosopher Rene] Descartes put forth this mind-matter duality, [where] the mind is outside of regular physics and intervenes on the physical world, says Hardy.

To test this idea, Hardy 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 doesnt 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.

[If] you only saw a violation of quantum theory when you had systems that might be regarded as conscious, humans or other animals, that would certainly be exciting. I cant imagine a more striking experimental result in physics than that, Hardy says. Wed want to debate as to what that meant.

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. It wouldnt settle the question, but it would certainly have a strong bearing on the issue of free will, says Hardy.

Nicolas Gisin at the University of Geneva in Switzerland thinks Hardys proposal makes plenty of sense, but hes sceptical of using unstructured EEG signals to switch settings on devices. Thats akin to using the brain as a random number generator, says Gisin. He would rather see an experiment where the conscious intent of humans is used to perform the switching but that would be experimentally more challenging.

Either way, he wants to see the experiment done. There is an enormous probability that nothing special will happen, and that quantum physics will not change, says Gisin. But if someone does the experiment and gets a surprising result, the reward is enormous. It would be the first time we as scientists can put our hands on this mind-body or problem of consciousness.

Journal reference: arXiv, DOI: 1705.04620v1

More on these topics:

Read more:

A classic quantum test could reveal the limits of the human mind - New Scientist