Something on the order of 651 million passengers traveled by air last year in the United States. Assuming that most of them wanted to go through airport security as quickly as possible, that means that thousands of under-paid and under-trained TSA officers, grown men and women turned professional genital-gazers, closely examined roughly 300 million penises and 600 million breasts for your safety. The whole body imaging systems inserted into the civilian air traffic experience in the 21st century have repeatedly been the focus of vociferous complaint, whether for reasons of privacy or radiation exposure, and just as fervently defended as a necessary and minimally inconvenient tool in the policing of everyday safety, but at least one thing about the wide-spread deployment of these technologies seems certain: their use constitutes the largest-scale production of erotic photography in the history of the world.

Should these images concern us? Or is the queasy discomfort that many feel, whether or not they choose to have their bodies so imaged, merely the growing pains of a shift-in-progress between competing conceptions of public privacy? It seems to me that we should be very concerned indeed, for the effect of this technology being widely applied throughout our airports is the creation of a new pre-requisite, a new burden, that needs to be met before one can efficiently travel throughout the country: that in order to fully participate in modern, post-industrial society we must cede control over which parts of our bodies are exposed and which left to remain private.

In his collection Concealment and Exposure, Thomas Nagel claims that "the boundary between what we reveal and what we do not, and some control over that boundary, is among the most important attributes of our humanity," arguing that the maintenance of that membrane of privacy is one of the principal challenges of a functioning society. "The awareness of how one appears from outside," he reminds us, "is a constant of human life, sometimes burdensome, sometimes an indispensable resource." The TSA's penetrating vision scans through the signs that constitute our chosen self-presentations through to the irreducibly biological, frequently loathed, and often painfully involuntary markers of bare species identity, in essence asking millions of people to swap their existences as unique, autonomous persons for the illusion of secure transportation, with a digitized photograph of their genitalia as the medium of exchange.