Tertuliano Maximo Afonso, the hero of “The Double,” is a middle-aged divorced history teacher. One day, on a colleague’s advice, he rents a videotape with a comedy titled “The Stubborn Hunter Will Shoot the Game.” And he discovers that the performer in one of the episodic roles—who isn’t even mentioned in the credits—looks exactly like him, like two drops of water. Searching for this man turns into a real obsession for Tertuliano, a journey into the very heart of metaphysical darkness…