I’m increasingly in awe of Simon’s hunger for deeply abstract constructions and meanings. He loves talking about what he’s just learned and the subject often sounds difficult to grasp at first, so I ask him for explanations. He is very patient with my lack of immediate understanding. “But how come 2 equals 2 x 2?” I ask, “2 can’t equal 4!” – “Don’t you see, Mom? It’s a variable, not a literal!” he answers.