Lie detectors and epistemic duty
The British government is about to introduce compulsory lie detector tests for sex offenders released on parole. The British police want to use lie detectors in the detection of crime. Is this the right thing to do?
The answer to that question depends on a complex set of duties. Obviously it is highly desirable to prevent people on parole committing crimes. Equally obviously it is highly desirable to catch criminals (only when the laws are just, of course). For this reason we are tempted to latch onto anything that promises improvements. The government and the pilot study they are basing their proposal on are promising us improvements by using lie detectors. Others elsewhere have considered whether lie detectors do in fact offer better outcomes . Even if lie detectors do offer better outcomes, which they might do whether or not they are good at detecting lies, that still wouldn’t make it right to use them.
A highly significant duty that bears on the question is the epistemic duty borne by the law and by the police, the epistemic duty to know the truth of guilt and innocence. Here I am concerned only with that duty. I do not consider other duties, such as protection from harm, that might be served by deterrent effects achieved independently of knowing the truth.Read More »Lie detectors and epistemic duty