Lithgow, who has lately “dwindled” from 6-foot-4 to 6-foot-3 but maintains a big man’s big personality, bubbled with interest as he loped from canvas to canvas. A collector of art and also of curators, he occasionally asked Stein, who has led him on many such tours, about the painter’s biography and method and world. I wondered if he was making mental notes on how character arises from circumstance to produce, as he has produced, so many extremes of feeling. But later he told me that while certainly noticing Schjerfbeck’s “combination of great technique and deeply felt emotion” he was mostly thinking wistfully about the art he might have made if he’d chosen that life “and been good enough.”