Letter to Elizabeth,
I was thinking of the book you're reading on quantum physics and postulating how particle physics could relate to the social world, when I remembered you jokingly saying you don't want your molecules intermingling with certain people. I understand and trust me, in a very real sense we never touch anything. Everything we touch when reduced to the quantum level is electromagnetic repulsion. Surrounding every nucleus of every atom or molecule in our body is a sphere of negatively charged electrons orbiting at near light speed. Since they're orbiting so fast around such an extraordinarily small space, the electrons create an impenetrable sphere, sort of like an elite bodyguard of soldiers that will never allow another electron to touch or pass through.