There are a number of themes present in Martin Scorsese‘s Shutter Island, but the one most significant to the experience of the film is uncertainty. From the first moment we meet U.S. Marshal Teddy Daniels (Leonardo DiCaprio) and his partner Chuck (Mark Ruffalo), we’re thrust into a world of pure pandemonium, where it’s not just the chaos of the criminally insane that keeps us intensely uneasy, but also the aloof and decidedly dubious men in charge of the facility on the island. There’s nothing here to hold on to, and no technique sets an audience on edge quite so effectively. At one point in the film Teddy comes upon the cell of George Noyce (Jackie Earle Haley), one of the more lucid inmates and a man Teddy has been searching for. The two men bicker, canvassing their situation while keeping us firmly in the fog, then Noyce comes face to face with the Marshal, “Don’t you get it…? You’re a rat in a maze.” He may as well be looking right through the lens, into the audience.