evidence: In my youth I did a lot of skin diving. One time I was ten feet underwater by some undulating eelgrass, and suddenly it opened to reveal a five-foot shark against the sand. That does something to your nervous system. It’s the same when you come across a bear in the wild. And you can have these experiences with people, too. I once ran into a sadhu [a Hindu holy man] way up in the Himalayas. It was sleeting and snowing heavily. He had a long beard and wore nothing but a loincloth. His eyes were huge! I said hello. He nodded. I pointed to the camera on my chest, indicating that I’d like to take a photo of him. He politely asked me not to in perfect English. I replied by saying something incredibly stupid: I asked him where he’d learned English. He said, "From my parents; where’d you learn English?" Wham! That guy was something else. Whether it’s with sharks or bears or sadhus, that type of wham experience shakes your foundations in a way an iPad never will. It has to do with contact. As Thoreau wrote in The Maine Woods: "Contact! Contact!"