Frank Cottrell Boyce (of whom more here and here) recently wrote an article about his favourite Hitchcock film which contains this striking final paragraph:
"Hitchcock is the great Catholic artist, returning again and again to the themes of the fallen nature of creation. Sometimes – The Wrong Man,The Birds – this comes out as a bleakly thrilling feeling that everyone is guilty. In Notorious, however (and in Shadow of a Doubt, Psycho, North by Northwest and Vertigo), it plays the opposite way – that the world is fallen and therefore the best are only different from the worst by the grace of God; that our worst failings are forgivable and repairable; and that no matter how compromised we are, we can – and must – love one another. It's the reason his great thrillers are also great love stories. It's the source of the power of that last shot – a hungover pietà – of Grant carrying Bergman out of the house of shadows and into the possibility of love."
Perhaps that's a question for some future exam paper: "Hitchcock is the great Catholic artist. Discuss."