Imagine for a moment that it is the year 2020. An American company has developed a mind-reading device, called the "brain wave recorder" ("BWR"). The BWR is a highly sensitive instrument that detects electrical impulses from any brain within ten feet of the machine. Though previously thought impossible, the BWR can discern the following information about the target individual: (1) whether he or she is happy, sad, anxious, depressed, or irritable; (2) whether he or she is even slightly sexually aroused; (3) whether he or she is taking any medication (and if so, what the medication is); (4) if a female subject, whether she is pregnant; (5) whether he or she is experiencing a feeling of guilt or remorse; and (6) whether he or she is having aggressive impulses toward another person or persons. At this stage in its development, we do not know whether or not the BWR will advance beyond detection of this information and whether or not it will become generally available to the public. It is currently a technology that belongs exclusively to the government and to extremely wealthy private collectors. Under Professor Orin Kerr's provocative and interesting thesis, federal or state police could use the BWR on innocent people without implicating their Fourth Amendment rights against unreasonable searches and seizures. To be more concrete, if, for example, the police were to utilize the BWR to determine whether John Doe - a man who neighbors say seems "strange" and doesn't "fit in" - feels sexually aroused when he is in the presence of women, the man could not complain of an invasion of any Fourth Amendment reasonable expectation of privacy. On Kerr's analysis, while existing Fourth Amendment doctrine nominally protects normatively and empirically reasonable expectations of privacy, in practice, in almost all cases, the doctrine protects only property (in a broad and flexible sense, so that it includes rented spaces, for example) but not privacy. Because the BWR reads Doe's internal state without physically trespassing on his property, the regulation of its use - as a matter of most of the case law - should be left to Congress. As a normative matter, Kerr proposes that the Supreme Court defer to Congress in the area of handling the privacy implications of evolving technologies.
Sherry F. Colb,
A World Without Privacy: Why Property Does Not Define the Limits of the Right Against Unreasonable Searches and Seizures,
Mich. L. Rev.
Available at: https://repository.law.umich.edu/mlr/vol102/iss5/2