Fascinating and frightening article from The Chronicle of Higher Education. It asks the question of whether we will have mental privacy once brain scans are good enough to interpret our actual thoughts - which, to a limited extent, they are already capable of.
Imagine that psychologists are scanning a patients' brain, for some basic research purpose. As they do so, they stumble across a fleeting thought that their equipment is able to decode: The patient has committed a murder, or is thinking of committing one soon. What would the researchers be obliged to do with that information?...
Under current doctrine, it might be consistent to accept all of those scans as permissible <in court>. After all, the scans are no more intrusive than a blood draw, and they measure physical characteristics, like blood flow and electrical impulses....
What's more, some scholars think that lie detectors, or concealed-information detectors, are already working far better than acknowledged by analysts or by courts, which generally but not completely forbid their use. The machines are far from perfect, but juries rely on all sorts of faulty folk wisdom in determining who is lying and who is telling the truth. (Crucially, courts have excluded the detectors not on principle but because they have not won the approval of scientists.)