Philosopher René Descartes famously declared “I think therefore I am” as proof of his existence. However, when I studied that proposition years ago, I just assumed that everyone else had a little voice – an essential “me” – that provides a constant stream of consciousness in their heads, too. Usually speaking in full sentences or at the least in understandable fragments. Imagine my surprise when a friend on Facebook posted a viral tweet that blew up that idea. “Fun fact: some people have an internal narrative and some don’t.