Baseball has served as a marker of time in America, a constant across the years explains James Earl Jones in his role as fictional writer Terence Mann in the 1989 film “Field of Dreams.” “People will come,” he tells his new friend Ray, played by Kevin Costner, a man who has plowed under his corn crop in Iowa to build an improbable baseball field. “And they’ll watch the game, and it’ll be as if they’d dipped themselves in magic waters.”