I   was standing next to my son in the cold. We weren’t speaking, but the silence was companionable. I thought it was, anyway, though the morning had been full of acrimony. There’d been a fight about the shower, a fight with his sister about toast (“I’m sorry to have to say this,” she told me, “but I wish I had a different mother”), a fight about high, yelping laughter, not welcome at any time of day, least of all before 8 AM . But all of that had dissipated, floating away when we stepped outside, and now my son and I were on the sidewalk, waiting for the field trip to begin.   “My hands,” he said with sorrow and held them up for me. “Where are your mittens?” He shook his head.   “We talked about this,” I said, and gave him mine. It was the coldest day of the year, and the trip to the botanical gardens had almost been canceled. Part of me, naturally, had hoped for a cancellation, but a more forward-thinking part was glad we were going through with it.…