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We'd love to help on that, but it would be much more effective if your friend could follow up with some specifics in his or her own words. We've written so much on the topic, generally searchable via the phrase "Bell Inequality", that we have little to add. I think it's fair to say that both quantum mechanics and relativity shake up a lot of basic ideas about the universe. That doesn't mean that they leave nothing of ordinary logic. just that what's left is modified- especially in the case of quantum mechanics.
(published on 09/11/2013)
Any measurement process that has a permanent effect on the system of interest causes the collapse of the wavefunction to a particular state, regardless of whether/how the results are interpreted by a human being. As long as the measurement device is on and recording, the state will be altered. Take temperature measurements, as an analogy. Although one tends to neglect, thermometers have a non-zero heat capacity in real life, therefore when you dip one into warm water, its temperature will be slightly decreased. Dip a thermometer in hot water, wait 1 minute, take it out and dip another one. The second time you measure will give you a lower measurement, compared to the case if you totally omitted the first measurement. This will happen whether you look at the mercury level or not, your dog watches the mercury level or not. What causes a change is the thermometer itself, not existence of a conscious mind watching it. In quantum case, the measurement device causes a change just because it records the state (not because of a side effect).
p.s. The vast majority of modern experiments of this type use automatic fast recording of the "which-way" data that are measured. There's no direct observation by people until the overall results are done. As Tunc wrote, it's the recording which sets up some physical difference in the outside world that depends on which-way. That breaks the interference between the paths. Mike W.
(published on 06/13/2015)
You're quite right that a conspiracy involving both the "random" or "free will" detector settings and the supposedly entangled test particles could produce the observed violations of Bell's Inequalities. It would have to be quite a conspiracy, in which apparently random events in two remote detectors and in some particle source were all pre-choreographed by some entity determined to mess with our minds. So the conclusion is that either quantum events have truly random outcomes, in principle not predictable from any prior facts about the universe, or absolutely everything is exactly determined in an amazing pseudo-random conspiracy. Either view is logically consistent, but most of us accept the random version.
As for how this randomness differs from the traditional concept of "free will", the issue does not concern "free". It concerns "will". Something that comes from no prior fact about the universe is not what we usually think of as "will", which flows from a prior mental state. If one thinks of "will" as a non-local variable, then one could say that it might be involved. That doesn't seem to fit well with what we know happens to thoughts in response to various direct physical and chemical events in the brain, which is as local as any other physical object.
p.s. That MIT article proposes using distant quasars to get the random detector settings. The idea is that it's really hard to imagine them both being in on the same extremely detailed conspiracy. I heard that a fellow at the South Pole who started worrying about these issues when he took a class on them from me had an even better idea along the same lines. Use the cosmic microwave background radiation from opposite directions. Alas, at least in our standard picture, the homogeneity of the CMB is attributed to inflationary causal connections between every part of the visible universe. So even these experiments wouldn't logically rule out the conspiracy idea. They would certainly help dramatize its absurdity.
(published on 07/05/2015)
There's some nice discussion of these topics (and many others) in Scott Aaronson's book "Quantum Computing Since Democritus".
Again, there's certainly nothing in these Bell violation experiments to discourage the idea that some of our choices are "free". It's hard to see, however, how those free quantum choices can be the result of anything we'd call "will".
(published on 07/07/2015)