The first time I heard about Locard’s Exchange Principle, I was reading a detective novel. The main character was explaining to his less-experienced colleague that
a French man in the late 1800‘s postulated that, at every crimes scene, there is a transfer of matter between anyone or anything that enters or leaves the scene. His point is that we all leave -- sometimes, microscopic -- footprints. Locard’s Exchange Principle is taught in beginner’s Forensics classes. When one of my daughters was attending Emma Willard, I saw a reference to Locard in one of the high school forensics textbooks. What captivated my attention was the possibility that we do not merely exchange matter. Wouldn’t it be reasonable to assume that we exchange parts of our emotional and intellectual selves as well? It strikes me that, whenever we are in the presence of others, we leave a bit or ourselves and they entrust something of themselves with us. Once I turned over that particular thought, the idea of placing a virtual bubble around ourselves as suggested by many New Age practitioners made a kind of sense to me. How else to repel someone’s unwanted negativity, anger, depression? It made me really think about my part in every day situations. What about the exchange with the cashier at Walmart, or the waitress at the roadside stop, or person who steps out in front of my car unexpectedly? What did I want to leave of myself? What was I willing to pick up from them? I can’t help but wonder what Locard would have to say about that?