Mark Ruffalo’s aim is True

DOMINICK AND THOMAS BIRDSEY ARE AS DIFFERENT AS identical twins can be. Born on opposite sides of midnight on New Year’s Eve 1950, they began life at the end of one decade and the beginning of the next—with separate birthdays and, as students during the Vietnam War, divergent draft numbers. When we meet them in I Know This Much Is True, an emotional HBO miniseries based on Wally Lamb’s 1998 best seller, the brothers (both played by Mark Ruffalo) are 40, and the disparities between them couldn’t be clearer. Thomas, a paranoid schizophrenic, has just walked into a public library with a knife and sliced off his own hand.

Dominick appears